xref: /petsc/src/mat/impls/sbaij/seq/sbaijfact.c (revision 9b0e81ee14297530cb857db49c9c565cd126b969)
1 /* Using Modified Sparse Row (MSR) storage.
2 See page 85, "Iterative Methods ..." by Saad. */
3 
4 /*$Id: sbaijfact.c,v 1.38 2000/10/31 16:06:00 hzhang Exp hzhang $*/
5 /*
6     Symbolic U^T*D*U factorization for SBAIJ format. Modified from SSF of YSMP.
7 */
8 #include "sbaij.h"
9 #include "src/mat/impls/baij/seq/baij.h"
10 #include "src/vec/vecimpl.h"
11 #include "src/inline/ilu.h"
12 #include "include/petscis.h"
13 
14 #undef __FUNC__
15 #define __FUNC__ "MatCholeskyFactorSymbolic_SeqSBAIJ"
16 int MatCholeskyFactorSymbolic_SeqSBAIJ(Mat A,IS perm,PetscReal f,Mat *B)
17 {
18   Mat_SeqSBAIJ *a = (Mat_SeqSBAIJ*)A->data,*b;
19   int         *rip,ierr,i,mbs = a->mbs,*ai,*aj;
20   int         *jutmp,bs = a->bs,bs2=a->bs2;
21   int         m,nzi,realloc = 0;
22   int         *jl,*q,jumin,jmin,jmax,juptr,nzk,qm,*iu,*ju,k,j,vj,umax,maxadd;
23   /* PetscTruth  ident; */
24 
25   PetscFunctionBegin;
26   PetscValidHeaderSpecific(perm,IS_COOKIE);
27   if (A->M != A->N) SETERRQ(PETSC_ERR_ARG_WRONG,"matrix must be square");
28 
29   /* check whether perm is the identity mapping */
30   /*
31   ierr = ISView(perm, VIEWER_STDOUT_SELF);CHKERRA(ierr);
32   ierr = ISIdentity(perm,&ident);CHKERRQ(ierr);
33   printf("ident = %d\n", ident);
34   */
35   ierr = ISGetIndices(perm,&rip);CHKERRQ(ierr);
36   for (i=0; i<mbs; i++){
37     if (rip[i] != i){
38       a->permute = PETSC_TRUE;
39       /* printf("non-trivial perm\n"); */
40       break;
41     }
42   }
43 
44   if (!a->permute){ /* without permutation */
45     ai = a->i; aj = a->j;
46   } else {       /* non-trivial permutation */
47     ierr = MatReorderingSeqSBAIJ(A, perm);CHKERRA(ierr);
48     ai = a->inew; aj = a->jnew;
49   }
50 
51   /* initialization */
52   /* Don't know how many column pointers are needed so estimate.
53      Use Modified Sparse Row storage for u and ju, see Sasd pp.85 */
54   iu   = (int*)PetscMalloc((mbs+1)*sizeof(int));CHKPTRQ(iu);
55   umax = (int)(f*ai[mbs] + 1); umax += mbs + 1;
56   ju   = (int*)PetscMalloc(umax*sizeof(int));CHKPTRQ(ju);
57   iu[0] = mbs+1;
58   juptr = mbs;
59   jl =  (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(jl);
60   q  =  (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(q);
61   for (i=0; i<mbs; i++){
62     jl[i] = mbs; q[i] = 0;
63   }
64 
65   /* for each row k */
66   for (k=0; k<mbs; k++){
67     nzk = 0; /* num. of nz blocks in k-th block row with diagonal block excluded */
68     q[k] = mbs;
69     /* initialize nonzero structure of k-th row to row rip[k] of A */
70     jmin = ai[rip[k]];
71     jmax = ai[rip[k]+1];
72     for (j=jmin; j<jmax; j++){
73       vj = rip[aj[j]]; /* col. value */
74       if(vj > k){
75         qm = k;
76         do {
77           m  = qm; qm = q[m];
78         } while(qm < vj);
79         if (qm == vj) {
80           printf(" error: duplicate entry in A\n"); break;
81         }
82         nzk++;
83         q[m] = vj;
84         q[vj] = qm;
85       } /* if(vj > k) */
86     } /* for (j=jmin; j<jmax; j++) */
87 
88     /* modify nonzero structure of k-th row by computing fill-in
89        for each row i to be merged in */
90     i = k;
91     i = jl[i]; /* next pivot row (== mbs for symbolic factorization) */
92     /* printf(" next pivot row i=%d\n",i); */
93     while (i < mbs){
94       /* merge row i into k-th row */
95       nzi = iu[i+1] - (iu[i]+1);
96       jmin = iu[i] + 1; jmax = iu[i] + nzi;
97       qm = k;
98       for (j=jmin; j<jmax+1; j++){
99         vj = ju[j];
100         do {
101           m = qm; qm = q[m];
102         } while (qm < vj);
103         if (qm != vj){
104          nzk++; q[m] = vj; q[vj] = qm; qm = vj;
105         }
106       }
107       i = jl[i]; /* next pivot row */
108     }
109 
110     /* add k to row list for first nonzero element in k-th row */
111     if (nzk > 0){
112       i = q[k]; /* col value of first nonzero element in U(k, k+1:mbs-1) */
113       jl[k] = jl[i]; jl[i] = k;
114     }
115     iu[k+1] = iu[k] + nzk;   /* printf(" iu[%d]=%d, umax=%d\n", k+1, iu[k+1],umax);*/
116 
117     /* allocate more space to ju if needed */
118     if (iu[k+1] > umax) { printf("allocate more space, iu[%d]=%d > umax=%d\n",k+1, iu[k+1],umax);
119       /* estimate how much additional space we will need */
120       /* use the strategy suggested by David Hysom <hysom@perch-t.icase.edu> */
121       /* just double the memory each time */
122       maxadd = umax;
123       if (maxadd < nzk) maxadd = (mbs-k)*(nzk+1)/2;
124       umax += maxadd;
125 
126       /* allocate a longer ju */
127       jutmp = (int*)PetscMalloc(umax*sizeof(int));CHKPTRQ(jutmp);
128       ierr  = PetscMemcpy(jutmp,ju,iu[k]*sizeof(int));CHKERRQ(ierr);
129       ierr  = PetscFree(ju);CHKERRQ(ierr);
130       ju    = jutmp;
131       realloc++; /* count how many times we realloc */
132     }
133 
134     /* save nonzero structure of k-th row in ju */
135     i=k;
136     jumin = juptr + 1; juptr += nzk;
137     for (j=jumin; j<juptr+1; j++){
138       i=q[i];
139       ju[j]=i;
140     }
141   }
142 
143   if (ai[mbs] != 0) {
144     PetscReal af = ((PetscReal)iu[mbs])/((PetscReal)ai[mbs]);
145     PLogInfo(A,"MatCholeskyFactorSymbolic_SeqSBAIJ:Reallocs %d Fill ratio:given %g needed %g\n",realloc,f,af);
146     PLogInfo(A,"MatCholeskyFactorSymbolic_SeqSBAIJ:Run with -pc_lu_fill %g or use \n",af);
147     PLogInfo(A,"MatCholeskyFactorSymbolic_SeqSBAIJ:PCLUSetFill(pc,%g);\n",af);
148     PLogInfo(A,"MatCholeskyFactorSymbolic_SeqSBAIJ:for best performance.\n");
149   } else {
150      PLogInfo(A,"MatCholeskyFactorSymbolic_SeqSBAIJ:Empty matrix.\n");
151   }
152 
153   ierr = ISRestoreIndices(perm,&rip);CHKERRQ(ierr);
154   ierr = PetscFree(q);CHKERRQ(ierr);
155   ierr = PetscFree(jl);CHKERRQ(ierr);
156 
157   /* put together the new matrix */
158   ierr = MatCreateSeqSBAIJ(A->comm,bs,bs*mbs,bs*mbs,0,PETSC_NULL,B);CHKERRQ(ierr);
159   /* PLogObjectParent(*B,iperm); */
160   b = (Mat_SeqSBAIJ*)(*B)->data;
161   ierr = PetscFree(b->imax);CHKERRQ(ierr);
162   b->singlemalloc = PETSC_FALSE;
163   /* the next line frees the default space generated by the Create() */
164   ierr = PetscFree(b->a);CHKERRQ(ierr);
165   ierr = PetscFree(b->ilen);CHKERRQ(ierr);
166   b->a          = (MatScalar*)PetscMalloc((iu[mbs]+1)*sizeof(MatScalar)*bs2);CHKPTRQ(b->a);
167   b->j          = ju;
168   b->i          = iu;
169   b->diag       = 0;
170   b->ilen       = 0;
171   b->imax       = 0;
172   b->row        = perm;
173   ierr          = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
174   b->icol       = perm;
175   ierr          = PetscObjectReference((PetscObject)perm);CHKERRQ(ierr);
176   b->solve_work = (Scalar*)PetscMalloc((bs*mbs+bs)*sizeof(Scalar));CHKPTRQ(b->solve_work);
177   /* In b structure:  Free imax, ilen, old a, old j.
178      Allocate idnew, solve_work, new a, new j */
179   PLogObjectMemory(*B,(iu[mbs]-mbs)*(sizeof(int)+sizeof(MatScalar)));
180   b->s_maxnz = b->s_nz = iu[mbs];
181 
182   (*B)->factor                 = FACTOR_CHOLESKY;
183   (*B)->info.factor_mallocs    = realloc;
184   (*B)->info.fill_ratio_given  = f;
185   if (ai[mbs] != 0) {
186     (*B)->info.fill_ratio_needed = ((PetscReal)iu[mbs])/((PetscReal)ai[mbs]);
187   } else {
188     (*B)->info.fill_ratio_needed = 0.0;
189   }
190 #ifdef TEMP
191   for (k=0; k<mbs; k++){
192     nzk = b->i[k+1] - b->i[k];
193     printf("\n b->i[%d]: %d, nzk: %d\n",k,b->i[k],nzk);
194     jmin = b->i[k]; jmax = b->i[k+1];
195     for (j=jmin; j<jmax; j++){
196       printf(" %d,",b->j[j]);
197     }
198   }
199 #endif
200   PetscFunctionReturn(0);
201 }
202 
203 #undef __FUNC__
204 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_N"
205 int MatCholeskyFactorNumeric_SeqSBAIJ_N(Mat A,Mat *B)
206 {
207   Mat                C = *B;
208   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
209   IS                 isrow = b->row,isicol = b->icol;
210   int                *r,*ic,ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
211   int                *ajtmpold,*ajtmp,nz,row,bslog,*ai=a->i,*aj=a->j,k,flg;
212   int                *diag_offset=b->diag,diag,bs=a->bs,bs2 = a->bs2,*v_pivots,*pj;
213   MatScalar          *ba = b->a,*aa = a->a,*pv,*v,*rtmp,*multiplier,*v_work,*pc,*w;
214 
215   PetscFunctionBegin;
216   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
217   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
218   rtmp = (MatScalar*)PetscMalloc(bs2*(n+1)*sizeof(MatScalar));CHKPTRQ(rtmp);
219   ierr = PetscMemzero(rtmp,bs2*(n+1)*sizeof(MatScalar));CHKERRQ(ierr);
220   /* generate work space needed by dense LU factorization */
221   v_work     = (MatScalar*)PetscMalloc(bs*sizeof(int) + (bs+bs2)*sizeof(MatScalar));CHKPTRQ(v_work);
222   multiplier = v_work + bs;
223   v_pivots   = (int*)(multiplier + bs2);
224 
225   /* flops in while loop */
226   bslog = 2*bs*bs2;
227 
228   for (i=0; i<n; i++) {
229     nz    = bi[i+1] - bi[i];
230     ajtmp = bj + bi[i];
231     for  (j=0; j<nz; j++) {
232       ierr = PetscMemzero(rtmp+bs2*ajtmp[j],bs2*sizeof(MatScalar));CHKERRQ(ierr);
233     }
234     /* load in initial (unfactored row) */
235     nz       = ai[r[i]+1] - ai[r[i]];
236     ajtmpold = aj + ai[r[i]];
237     v        = aa + bs2*ai[r[i]];
238     for (j=0; j<nz; j++) {
239       ierr = PetscMemcpy(rtmp+bs2*ic[ajtmpold[j]],v+bs2*j,bs2*sizeof(MatScalar));CHKERRQ(ierr);
240     }
241     row = *ajtmp++;
242     while (row < i) {
243       pc = rtmp + bs2*row;
244 /*      if (*pc) { */
245       for (flg=0,k=0; k<bs2; k++) { if (pc[k]!=0.0) { flg =1; break; }}
246       if (flg) {
247         pv = ba + bs2*diag_offset[row];
248         pj = bj + diag_offset[row] + 1;
249         Kernel_A_gets_A_times_B(bs,pc,pv,multiplier);
250         nz = bi[row+1] - diag_offset[row] - 1;
251         pv += bs2;
252         for (j=0; j<nz; j++) {
253           Kernel_A_gets_A_minus_B_times_C(bs,rtmp+bs2*pj[j],pc,pv+bs2*j);
254         }
255         PLogFlops(bslog*(nz+1)-bs);
256       }
257         row = *ajtmp++;
258     }
259     /* finished row so stick it into b->a */
260     pv = ba + bs2*bi[i];
261     pj = bj + bi[i];
262     nz = bi[i+1] - bi[i];
263     for (j=0; j<nz; j++) {
264       ierr = PetscMemcpy(pv+bs2*j,rtmp+bs2*pj[j],bs2*sizeof(MatScalar));CHKERRQ(ierr);
265     }
266     diag = diag_offset[i] - bi[i];
267     /* invert diagonal block */
268     w = pv + bs2*diag;
269     Kernel_A_gets_inverse_A(bs,w,v_pivots,v_work);
270   }
271 
272   ierr = PetscFree(rtmp);CHKERRQ(ierr);
273   ierr = PetscFree(v_work);CHKERRQ(ierr);
274   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
275   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
276   C->factor = FACTOR_LU;
277   C->assembled = PETSC_TRUE;
278   PLogFlops(1.3333*bs*bs2*b->mbs); /* from inverting diagonal blocks */
279   PetscFunctionReturn(0);
280 }
281 
282 /*
283       Version for when blocks are 7 by 7
284 */
285 #undef __FUNC__
286 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_7"
287 int MatCholeskyFactorNumeric_SeqSBAIJ_7(Mat A,Mat *B)
288 {
289   Mat         C = *B;
290   Mat_SeqBAIJ *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
291   IS          isrow = b->row,isicol = b->icol;
292   int         *r,*ic,ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
293   int         *ajtmpold,*ajtmp,nz,row;
294   int         *diag_offset = b->diag,idx,*ai=a->i,*aj=a->j,*pj;
295   MatScalar   *pv,*v,*rtmp,*pc,*w,*x;
296   MatScalar   p1,p2,p3,p4,m1,m2,m3,m4,m5,m6,m7,m8,m9,x1,x2,x3,x4;
297   MatScalar   p5,p6,p7,p8,p9,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15,x16;
298   MatScalar   x17,x18,x19,x20,x21,x22,x23,x24,x25,p10,p11,p12,p13,p14;
299   MatScalar   p15,p16,p17,p18,p19,p20,p21,p22,p23,p24,p25,m10,m11,m12;
300   MatScalar   m13,m14,m15,m16,m17,m18,m19,m20,m21,m22,m23,m24,m25;
301   MatScalar   p26,p27,p28,p29,p30,p31,p32,p33,p34,p35,p36;
302   MatScalar   p37,p38,p39,p40,p41,p42,p43,p44,p45,p46,p47,p48,p49;
303   MatScalar   x26,x27,x28,x29,x30,x31,x32,x33,x34,x35,x36;
304   MatScalar   x37,x38,x39,x40,x41,x42,x43,x44,x45,x46,x47,x48,x49;
305   MatScalar   m26,m27,m28,m29,m30,m31,m32,m33,m34,m35,m36;
306   MatScalar   m37,m38,m39,m40,m41,m42,m43,m44,m45,m46,m47,m48,m49;
307   MatScalar   *ba = b->a,*aa = a->a;
308 
309   PetscFunctionBegin;
310   ierr  = ISGetIndices(isrow,&r);CHKERRQ(ierr);
311   ierr  = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
312   rtmp  = (MatScalar*)PetscMalloc(49*(n+1)*sizeof(MatScalar));CHKPTRQ(rtmp);
313 
314   for (i=0; i<n; i++) {
315     nz    = bi[i+1] - bi[i];
316     ajtmp = bj + bi[i];
317     for  (j=0; j<nz; j++) {
318       x = rtmp+49*ajtmp[j];
319       x[0] = x[1] = x[2] = x[3] = x[4] = x[5] = x[6] = x[7] = x[8] = x[9] = 0.0;
320       x[10] = x[11] = x[12] = x[13] = x[14] = x[15] = x[16] = x[17] = 0.0;
321       x[18] = x[19] = x[20] = x[21] = x[22] = x[23] = x[24] = x[25] = 0.0 ;
322       x[26] = x[27] = x[28] = x[29] = x[30] = x[31] = x[32] = x[33] = 0.0 ;
323       x[34] = x[35] = x[36] = x[37] = x[38] = x[39] = x[40] = x[41] = 0.0 ;
324       x[42] = x[43] = x[44] = x[45] = x[46] = x[47] = x[48] = 0.0 ;
325     }
326     /* load in initial (unfactored row) */
327     idx      = r[i];
328     nz       = ai[idx+1] - ai[idx];
329     ajtmpold = aj + ai[idx];
330     v        = aa + 49*ai[idx];
331     for (j=0; j<nz; j++) {
332       x    = rtmp+49*ic[ajtmpold[j]];
333       x[0] =  v[0];  x[1] =  v[1];  x[2] =  v[2];  x[3] =  v[3];
334       x[4] =  v[4];  x[5] =  v[5];  x[6] =  v[6];  x[7] =  v[7];
335       x[8] =  v[8];  x[9] =  v[9];  x[10] = v[10]; x[11] = v[11];
336       x[12] = v[12]; x[13] = v[13]; x[14] = v[14]; x[15] = v[15];
337       x[16] = v[16]; x[17] = v[17]; x[18] = v[18]; x[19] = v[19];
338       x[20] = v[20]; x[21] = v[21]; x[22] = v[22]; x[23] = v[23];
339       x[24] = v[24]; x[25] = v[25]; x[26] = v[26]; x[27] = v[27];
340       x[28] = v[28]; x[29] = v[29]; x[30] = v[30]; x[31] = v[31];
341       x[32] = v[32]; x[33] = v[33]; x[34] = v[34]; x[35] = v[35];
342       x[36] = v[36]; x[37] = v[37]; x[38] = v[38]; x[39] = v[39];
343       x[40] = v[40]; x[41] = v[41]; x[42] = v[42]; x[43] = v[43];
344       x[44] = v[44]; x[45] = v[45]; x[46] = v[46]; x[47] = v[47];
345       x[48] = v[48];
346       v    += 49;
347     }
348     row = *ajtmp++;
349     while (row < i) {
350       pc  =  rtmp + 49*row;
351       p1  = pc[0];  p2  = pc[1];  p3  = pc[2];  p4  = pc[3];
352       p5  = pc[4];  p6  = pc[5];  p7  = pc[6];  p8  = pc[7];
353       p9  = pc[8];  p10 = pc[9];  p11 = pc[10]; p12 = pc[11];
354       p13 = pc[12]; p14 = pc[13]; p15 = pc[14]; p16 = pc[15];
355       p17 = pc[16]; p18 = pc[17]; p19 = pc[18]; p20 = pc[19];
356       p21 = pc[20]; p22 = pc[21]; p23 = pc[22]; p24 = pc[23];
357       p25 = pc[24]; p26 = pc[25]; p27 = pc[26]; p28 = pc[27];
358       p29 = pc[28]; p30 = pc[29]; p31 = pc[30]; p32 = pc[31];
359       p33 = pc[32]; p34 = pc[33]; p35 = pc[34]; p36 = pc[35];
360       p37 = pc[36]; p38 = pc[37]; p39 = pc[38]; p40 = pc[39];
361       p41 = pc[40]; p42 = pc[41]; p43 = pc[42]; p44 = pc[43];
362       p45 = pc[44]; p46 = pc[45]; p47 = pc[46]; p48 = pc[47];
363       p49 = pc[48];
364       if (p1  != 0.0 || p2  != 0.0 || p3  != 0.0 || p4  != 0.0 ||
365           p5  != 0.0 || p6  != 0.0 || p7  != 0.0 || p8  != 0.0 ||
366           p9  != 0.0 || p10 != 0.0 || p11 != 0.0 || p12 != 0.0 ||
367           p13 != 0.0 || p14 != 0.0 || p15 != 0.0 || p16 != 0.0 ||
368           p17 != 0.0 || p18 != 0.0 || p19 != 0.0 || p20 != 0.0 ||
369           p21 != 0.0 || p22 != 0.0 || p23 != 0.0 || p24 != 0.0 ||
370           p25 != 0.0 || p26 != 0.0 || p27 != 0.0 || p28 != 0.0 ||
371           p29 != 0.0 || p30 != 0.0 || p31 != 0.0 || p32 != 0.0 ||
372           p33 != 0.0 || p34 != 0.0 || p35 != 0.0 || p36 != 0.0 ||
373           p37 != 0.0 || p38 != 0.0 || p39 != 0.0 || p40 != 0.0 ||
374           p41 != 0.0 || p42 != 0.0 || p43 != 0.0 || p44 != 0.0 ||
375           p45 != 0.0 || p46 != 0.0 || p47 != 0.0 || p48 != 0.0 ||
376           p49 != 0.0) {
377         pv = ba + 49*diag_offset[row];
378         pj = bj + diag_offset[row] + 1;
379 	x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
380 	x5  = pv[4];  x6  = pv[5];  x7  = pv[6];  x8  = pv[7];
381 	x9  = pv[8];  x10 = pv[9];  x11 = pv[10]; x12 = pv[11];
382 	x13 = pv[12]; x14 = pv[13]; x15 = pv[14]; x16 = pv[15];
383 	x17 = pv[16]; x18 = pv[17]; x19 = pv[18]; x20 = pv[19];
384 	x21 = pv[20]; x22 = pv[21]; x23 = pv[22]; x24 = pv[23];
385 	x25 = pv[24]; x26 = pv[25]; x27 = pv[26]; x28 = pv[27];
386 	x29 = pv[28]; x30 = pv[29]; x31 = pv[30]; x32 = pv[31];
387 	x33 = pv[32]; x34 = pv[33]; x35 = pv[34]; x36 = pv[35];
388 	x37 = pv[36]; x38 = pv[37]; x39 = pv[38]; x40 = pv[39];
389 	x41 = pv[40]; x42 = pv[41]; x43 = pv[42]; x44 = pv[43];
390 	x45 = pv[44]; x46 = pv[45]; x47 = pv[46]; x48 = pv[47];
391 	x49 = pv[48];
392         pc[0]  = m1  = p1*x1  + p8*x2   + p15*x3  + p22*x4  + p29*x5  + p36*x6 + p43*x7;
393         pc[1]  = m2  = p2*x1  + p9*x2   + p16*x3  + p23*x4  + p30*x5  + p37*x6 + p44*x7;
394         pc[2]  = m3  = p3*x1  + p10*x2  + p17*x3  + p24*x4  + p31*x5  + p38*x6 + p45*x7;
395         pc[3]  = m4  = p4*x1  + p11*x2  + p18*x3  + p25*x4  + p32*x5  + p39*x6 + p46*x7;
396         pc[4]  = m5  = p5*x1  + p12*x2  + p19*x3  + p26*x4  + p33*x5  + p40*x6 + p47*x7;
397         pc[5]  = m6  = p6*x1  + p13*x2  + p20*x3  + p27*x4  + p34*x5  + p41*x6 + p48*x7;
398         pc[6]  = m7  = p7*x1  + p14*x2  + p21*x3  + p28*x4  + p35*x5  + p42*x6 + p49*x7;
399 
400         pc[7]  = m8  = p1*x8  + p8*x9   + p15*x10 + p22*x11 + p29*x12 + p36*x13 + p43*x14;
401         pc[8]  = m9  = p2*x8  + p9*x9   + p16*x10 + p23*x11 + p30*x12 + p37*x13 + p44*x14;
402         pc[9]  = m10 = p3*x8  + p10*x9  + p17*x10 + p24*x11 + p31*x12 + p38*x13 + p45*x14;
403         pc[10] = m11 = p4*x8  + p11*x9  + p18*x10 + p25*x11 + p32*x12 + p39*x13 + p46*x14;
404         pc[11] = m12 = p5*x8  + p12*x9  + p19*x10 + p26*x11 + p33*x12 + p40*x13 + p47*x14;
405         pc[12] = m13 = p6*x8  + p13*x9  + p20*x10 + p27*x11 + p34*x12 + p41*x13 + p48*x14;
406         pc[13] = m14 = p7*x8  + p14*x9  + p21*x10 + p28*x11 + p35*x12 + p42*x13 + p49*x14;
407 
408         pc[14] = m15 = p1*x15 + p8*x16  + p15*x17 + p22*x18 + p29*x19 + p36*x20 + p43*x21;
409         pc[15] = m16 = p2*x15 + p9*x16  + p16*x17 + p23*x18 + p30*x19 + p37*x20 + p44*x21;
410         pc[16] = m17 = p3*x15 + p10*x16 + p17*x17 + p24*x18 + p31*x19 + p38*x20 + p45*x21;
411         pc[17] = m18 = p4*x15 + p11*x16 + p18*x17 + p25*x18 + p32*x19 + p39*x20 + p46*x21;
412         pc[18] = m19 = p5*x15 + p12*x16 + p19*x17 + p26*x18 + p33*x19 + p40*x20 + p47*x21;
413         pc[19] = m20 = p6*x15 + p13*x16 + p20*x17 + p27*x18 + p34*x19 + p41*x20 + p48*x21;
414         pc[20] = m21 = p7*x15 + p14*x16 + p21*x17 + p28*x18 + p35*x19 + p42*x20 + p49*x21;
415 
416         pc[21] = m22 = p1*x22 + p8*x23  + p15*x24 + p22*x25 + p29*x26 + p36*x27 + p43*x28;
417         pc[22] = m23 = p2*x22 + p9*x23  + p16*x24 + p23*x25 + p30*x26 + p37*x27 + p44*x28;
418         pc[23] = m24 = p3*x22 + p10*x23 + p17*x24 + p24*x25 + p31*x26 + p38*x27 + p45*x28;
419         pc[24] = m25 = p4*x22 + p11*x23 + p18*x24 + p25*x25 + p32*x26 + p39*x27 + p46*x28;
420         pc[25] = m26 = p5*x22 + p12*x23 + p19*x24 + p26*x25 + p33*x26 + p40*x27 + p47*x28;
421         pc[26] = m27 = p6*x22 + p13*x23 + p20*x24 + p27*x25 + p34*x26 + p41*x27 + p48*x28;
422         pc[27] = m28 = p7*x22 + p14*x23 + p21*x24 + p28*x25 + p35*x26 + p42*x27 + p49*x28;
423 
424         pc[28] = m29 = p1*x29 + p8*x30  + p15*x31 + p22*x32 + p29*x33 + p36*x34 + p43*x35;
425         pc[29] = m30 = p2*x29 + p9*x30  + p16*x31 + p23*x32 + p30*x33 + p37*x34 + p44*x35;
426         pc[30] = m31 = p3*x29 + p10*x30 + p17*x31 + p24*x32 + p31*x33 + p38*x34 + p45*x35;
427         pc[31] = m32 = p4*x29 + p11*x30 + p18*x31 + p25*x32 + p32*x33 + p39*x34 + p46*x35;
428         pc[32] = m33 = p5*x29 + p12*x30 + p19*x31 + p26*x32 + p33*x33 + p40*x34 + p47*x35;
429         pc[33] = m34 = p6*x29 + p13*x30 + p20*x31 + p27*x32 + p34*x33 + p41*x34 + p48*x35;
430         pc[34] = m35 = p7*x29 + p14*x30 + p21*x31 + p28*x32 + p35*x33 + p42*x34 + p49*x35;
431 
432         pc[35] = m36 = p1*x36 + p8*x37  + p15*x38 + p22*x39 + p29*x40 + p36*x41 + p43*x42;
433         pc[36] = m37 = p2*x36 + p9*x37  + p16*x38 + p23*x39 + p30*x40 + p37*x41 + p44*x42;
434         pc[37] = m38 = p3*x36 + p10*x37 + p17*x38 + p24*x39 + p31*x40 + p38*x41 + p45*x42;
435         pc[38] = m39 = p4*x36 + p11*x37 + p18*x38 + p25*x39 + p32*x40 + p39*x41 + p46*x42;
436         pc[39] = m40 = p5*x36 + p12*x37 + p19*x38 + p26*x39 + p33*x40 + p40*x41 + p47*x42;
437         pc[40] = m41 = p6*x36 + p13*x37 + p20*x38 + p27*x39 + p34*x40 + p41*x41 + p48*x42;
438         pc[41] = m42 = p7*x36 + p14*x37 + p21*x38 + p28*x39 + p35*x40 + p42*x41 + p49*x42;
439 
440         pc[42] = m43 = p1*x43 + p8*x44  + p15*x45 + p22*x46 + p29*x47 + p36*x48 + p43*x49;
441         pc[43] = m44 = p2*x43 + p9*x44  + p16*x45 + p23*x46 + p30*x47 + p37*x48 + p44*x49;
442         pc[44] = m45 = p3*x43 + p10*x44 + p17*x45 + p24*x46 + p31*x47 + p38*x48 + p45*x49;
443         pc[45] = m46 = p4*x43 + p11*x44 + p18*x45 + p25*x46 + p32*x47 + p39*x48 + p46*x49;
444         pc[46] = m47 = p5*x43 + p12*x44 + p19*x45 + p26*x46 + p33*x47 + p40*x48 + p47*x49;
445         pc[47] = m48 = p6*x43 + p13*x44 + p20*x45 + p27*x46 + p34*x47 + p41*x48 + p48*x49;
446         pc[48] = m49 = p7*x43 + p14*x44 + p21*x45 + p28*x46 + p35*x47 + p42*x48 + p49*x49;
447 
448         nz = bi[row+1] - diag_offset[row] - 1;
449         pv += 49;
450         for (j=0; j<nz; j++) {
451 	  x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
452 	  x5  = pv[4];  x6  = pv[5];  x7  = pv[6];  x8  = pv[7];
453 	  x9  = pv[8];  x10 = pv[9];  x11 = pv[10]; x12 = pv[11];
454 	  x13 = pv[12]; x14 = pv[13]; x15 = pv[14]; x16 = pv[15];
455 	  x17 = pv[16]; x18 = pv[17]; x19 = pv[18]; x20 = pv[19];
456 	  x21 = pv[20]; x22 = pv[21]; x23 = pv[22]; x24 = pv[23];
457 	  x25 = pv[24]; x26 = pv[25]; x27 = pv[26]; x28 = pv[27];
458 	  x29 = pv[28]; x30 = pv[29]; x31 = pv[30]; x32 = pv[31];
459 	  x33 = pv[32]; x34 = pv[33]; x35 = pv[34]; x36 = pv[35];
460 	  x37 = pv[36]; x38 = pv[37]; x39 = pv[38]; x40 = pv[39];
461 	  x41 = pv[40]; x42 = pv[41]; x43 = pv[42]; x44 = pv[43];
462 	  x45 = pv[44]; x46 = pv[45]; x47 = pv[46]; x48 = pv[47];
463 	  x49 = pv[48];
464 	  x    = rtmp + 49*pj[j];
465 	  x[0]  -= m1*x1  + m8*x2   + m15*x3  + m22*x4  + m29*x5  + m36*x6 + m43*x7;
466 	  x[1]  -= m2*x1  + m9*x2   + m16*x3  + m23*x4  + m30*x5  + m37*x6 + m44*x7;
467 	  x[2]  -= m3*x1  + m10*x2  + m17*x3  + m24*x4  + m31*x5  + m38*x6 + m45*x7;
468 	  x[3]  -= m4*x1  + m11*x2  + m18*x3  + m25*x4  + m32*x5  + m39*x6 + m46*x7;
469 	  x[4]  -= m5*x1  + m12*x2  + m19*x3  + m26*x4  + m33*x5  + m40*x6 + m47*x7;
470 	  x[5]  -= m6*x1  + m13*x2  + m20*x3  + m27*x4  + m34*x5  + m41*x6 + m48*x7;
471 	  x[6]  -= m7*x1  + m14*x2  + m21*x3  + m28*x4  + m35*x5  + m42*x6 + m49*x7;
472 
473 	  x[7]  -= m1*x8  + m8*x9   + m15*x10 + m22*x11 + m29*x12 + m36*x13 + m43*x14;
474 	  x[8]  -= m2*x8  + m9*x9   + m16*x10 + m23*x11 + m30*x12 + m37*x13 + m44*x14;
475 	  x[9]  -= m3*x8  + m10*x9  + m17*x10 + m24*x11 + m31*x12 + m38*x13 + m45*x14;
476 	  x[10] -= m4*x8  + m11*x9  + m18*x10 + m25*x11 + m32*x12 + m39*x13 + m46*x14;
477 	  x[11] -= m5*x8  + m12*x9  + m19*x10 + m26*x11 + m33*x12 + m40*x13 + m47*x14;
478 	  x[12] -= m6*x8  + m13*x9  + m20*x10 + m27*x11 + m34*x12 + m41*x13 + m48*x14;
479 	  x[13] -= m7*x8  + m14*x9  + m21*x10 + m28*x11 + m35*x12 + m42*x13 + m49*x14;
480 
481 	  x[14] -= m1*x15 + m8*x16  + m15*x17 + m22*x18 + m29*x19 + m36*x20 + m43*x21;
482 	  x[15] -= m2*x15 + m9*x16  + m16*x17 + m23*x18 + m30*x19 + m37*x20 + m44*x21;
483 	  x[16] -= m3*x15 + m10*x16 + m17*x17 + m24*x18 + m31*x19 + m38*x20 + m45*x21;
484 	  x[17] -= m4*x15 + m11*x16 + m18*x17 + m25*x18 + m32*x19 + m39*x20 + m46*x21;
485 	  x[18] -= m5*x15 + m12*x16 + m19*x17 + m26*x18 + m33*x19 + m40*x20 + m47*x21;
486 	  x[19] -= m6*x15 + m13*x16 + m20*x17 + m27*x18 + m34*x19 + m41*x20 + m48*x21;
487 	  x[20] -= m7*x15 + m14*x16 + m21*x17 + m28*x18 + m35*x19 + m42*x20 + m49*x21;
488 
489 	  x[21] -= m1*x22 + m8*x23  + m15*x24 + m22*x25 + m29*x26 + m36*x27 + m43*x28;
490 	  x[22] -= m2*x22 + m9*x23  + m16*x24 + m23*x25 + m30*x26 + m37*x27 + m44*x28;
491 	  x[23] -= m3*x22 + m10*x23 + m17*x24 + m24*x25 + m31*x26 + m38*x27 + m45*x28;
492 	  x[24] -= m4*x22 + m11*x23 + m18*x24 + m25*x25 + m32*x26 + m39*x27 + m46*x28;
493 	  x[25] -= m5*x22 + m12*x23 + m19*x24 + m26*x25 + m33*x26 + m40*x27 + m47*x28;
494 	  x[26] -= m6*x22 + m13*x23 + m20*x24 + m27*x25 + m34*x26 + m41*x27 + m48*x28;
495 	  x[27] -= m7*x22 + m14*x23 + m21*x24 + m28*x25 + m35*x26 + m42*x27 + m49*x28;
496 
497 	  x[28] -= m1*x29 + m8*x30  + m15*x31 + m22*x32 + m29*x33 + m36*x34 + m43*x35;
498 	  x[29] -= m2*x29 + m9*x30  + m16*x31 + m23*x32 + m30*x33 + m37*x34 + m44*x35;
499 	  x[30] -= m3*x29 + m10*x30 + m17*x31 + m24*x32 + m31*x33 + m38*x34 + m45*x35;
500 	  x[31] -= m4*x29 + m11*x30 + m18*x31 + m25*x32 + m32*x33 + m39*x34 + m46*x35;
501 	  x[32] -= m5*x29 + m12*x30 + m19*x31 + m26*x32 + m33*x33 + m40*x34 + m47*x35;
502 	  x[33] -= m6*x29 + m13*x30 + m20*x31 + m27*x32 + m34*x33 + m41*x34 + m48*x35;
503 	  x[34] -= m7*x29 + m14*x30 + m21*x31 + m28*x32 + m35*x33 + m42*x34 + m49*x35;
504 
505 	  x[35] -= m1*x36 + m8*x37  + m15*x38 + m22*x39 + m29*x40 + m36*x41 + m43*x42;
506 	  x[36] -= m2*x36 + m9*x37  + m16*x38 + m23*x39 + m30*x40 + m37*x41 + m44*x42;
507 	  x[37] -= m3*x36 + m10*x37 + m17*x38 + m24*x39 + m31*x40 + m38*x41 + m45*x42;
508 	  x[38] -= m4*x36 + m11*x37 + m18*x38 + m25*x39 + m32*x40 + m39*x41 + m46*x42;
509 	  x[39] -= m5*x36 + m12*x37 + m19*x38 + m26*x39 + m33*x40 + m40*x41 + m47*x42;
510 	  x[40] -= m6*x36 + m13*x37 + m20*x38 + m27*x39 + m34*x40 + m41*x41 + m48*x42;
511 	  x[41] -= m7*x36 + m14*x37 + m21*x38 + m28*x39 + m35*x40 + m42*x41 + m49*x42;
512 
513 	  x[42] -= m1*x43 + m8*x44  + m15*x45 + m22*x46 + m29*x47 + m36*x48 + m43*x49;
514 	  x[43] -= m2*x43 + m9*x44  + m16*x45 + m23*x46 + m30*x47 + m37*x48 + m44*x49;
515 	  x[44] -= m3*x43 + m10*x44 + m17*x45 + m24*x46 + m31*x47 + m38*x48 + m45*x49;
516 	  x[45] -= m4*x43 + m11*x44 + m18*x45 + m25*x46 + m32*x47 + m39*x48 + m46*x49;
517 	  x[46] -= m5*x43 + m12*x44 + m19*x45 + m26*x46 + m33*x47 + m40*x48 + m47*x49;
518 	  x[47] -= m6*x43 + m13*x44 + m20*x45 + m27*x46 + m34*x47 + m41*x48 + m48*x49;
519 	  x[48] -= m7*x43 + m14*x44 + m21*x45 + m28*x46 + m35*x47 + m42*x48 + m49*x49;
520           pv   += 49;
521         }
522         PLogFlops(686*nz+637);
523       }
524       row = *ajtmp++;
525     }
526     /* finished row so stick it into b->a */
527     pv = ba + 49*bi[i];
528     pj = bj + bi[i];
529     nz = bi[i+1] - bi[i];
530     for (j=0; j<nz; j++) {
531       x      = rtmp+49*pj[j];
532       pv[0]  = x[0];  pv[1]  = x[1];  pv[2]  = x[2];  pv[3]  = x[3];
533       pv[4]  = x[4];  pv[5]  = x[5];  pv[6]  = x[6];  pv[7]  = x[7];
534       pv[8]  = x[8];  pv[9]  = x[9];  pv[10] = x[10]; pv[11] = x[11];
535       pv[12] = x[12]; pv[13] = x[13]; pv[14] = x[14]; pv[15] = x[15];
536       pv[16] = x[16]; pv[17] = x[17]; pv[18] = x[18]; pv[19] = x[19];
537       pv[20] = x[20]; pv[21] = x[21]; pv[22] = x[22]; pv[23] = x[23];
538       pv[24] = x[24]; pv[25] = x[25]; pv[26] = x[26]; pv[27] = x[27];
539       pv[28] = x[28]; pv[29] = x[29]; pv[30] = x[30]; pv[31] = x[31];
540       pv[32] = x[32]; pv[33] = x[33]; pv[34] = x[34]; pv[35] = x[35];
541       pv[36] = x[36]; pv[37] = x[37]; pv[38] = x[38]; pv[39] = x[39];
542       pv[40] = x[40]; pv[41] = x[41]; pv[42] = x[42]; pv[43] = x[43];
543       pv[44] = x[44]; pv[45] = x[45]; pv[46] = x[46]; pv[47] = x[47];
544       pv[48] = x[48];
545       pv   += 49;
546     }
547     /* invert diagonal block */
548     w = ba + 49*diag_offset[i];
549     ierr = Kernel_A_gets_inverse_A_7(w);CHKERRQ(ierr);
550   }
551 
552   ierr = PetscFree(rtmp);CHKERRQ(ierr);
553   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
554   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
555   C->factor = FACTOR_LU;
556   C->assembled = PETSC_TRUE;
557   PLogFlops(1.3333*343*b->mbs); /* from inverting diagonal blocks */
558   PetscFunctionReturn(0);
559 }
560 
561 /*
562       Version for when blocks are 7 by 7 Using natural ordering
563 */
564 #undef __FUNC__
565 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_7_NaturalOrdering"
566 int MatCholeskyFactorNumeric_SeqSBAIJ_7_NaturalOrdering(Mat A,Mat *B)
567 {
568   Mat          C = *B;
569   Mat_SeqBAIJ  *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
570   int          ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
571   int          *ajtmpold,*ajtmp,nz,row;
572   int          *diag_offset = b->diag,*ai=a->i,*aj=a->j,*pj;
573   MatScalar    *pv,*v,*rtmp,*pc,*w,*x;
574   MatScalar    x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15;
575   MatScalar    x16,x17,x18,x19,x20,x21,x22,x23,x24,x25;
576   MatScalar    p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12,p13,p14,p15;
577   MatScalar    p16,p17,p18,p19,p20,p21,p22,p23,p24,p25;
578   MatScalar    m1,m2,m3,m4,m5,m6,m7,m8,m9,m10,m11,m12,m13,m14,m15;
579   MatScalar    m16,m17,m18,m19,m20,m21,m22,m23,m24,m25;
580   MatScalar    p26,p27,p28,p29,p30,p31,p32,p33,p34,p35,p36;
581   MatScalar    p37,p38,p39,p40,p41,p42,p43,p44,p45,p46,p47,p48,p49;
582   MatScalar    x26,x27,x28,x29,x30,x31,x32,x33,x34,x35,x36;
583   MatScalar    x37,x38,x39,x40,x41,x42,x43,x44,x45,x46,x47,x48,x49;
584   MatScalar    m26,m27,m28,m29,m30,m31,m32,m33,m34,m35,m36;
585   MatScalar    m37,m38,m39,m40,m41,m42,m43,m44,m45,m46,m47,m48,m49;
586   MatScalar    *ba = b->a,*aa = a->a;
587 
588   PetscFunctionBegin;
589   rtmp  = (MatScalar*)PetscMalloc(49*(n+1)*sizeof(MatScalar));CHKPTRQ(rtmp);
590   for (i=0; i<n; i++) {
591     nz    = bi[i+1] - bi[i];
592     ajtmp = bj + bi[i];
593     for  (j=0; j<nz; j++) {
594       x = rtmp+49*ajtmp[j];
595       x[0] = x[1] = x[2] = x[3] = x[4] = x[5] = x[6] = x[7] = x[8] = x[9] = 0.0;
596       x[10] = x[11] = x[12] = x[13] = x[14] = x[15] = x[16] = x[17] = 0.0;
597       x[18] = x[19] = x[20] = x[21] = x[22] = x[23] = x[24] = x[25] = 0.0 ;
598       x[26] = x[27] = x[28] = x[29] = x[30] = x[31] = x[32] = x[33] = 0.0 ;
599       x[34] = x[35] = x[36] = x[37] = x[38] = x[39] = x[40] = x[41] = 0.0 ;
600       x[42] = x[43] = x[44] = x[45] = x[46] = x[47] = x[48] = 0.0 ;
601     }
602     /* load in initial (unfactored row) */
603     nz       = ai[i+1] - ai[i];
604     ajtmpold = aj + ai[i];
605     v        = aa + 49*ai[i];
606     for (j=0; j<nz; j++) {
607       x    = rtmp+49*ajtmpold[j];
608       x[0] =  v[0];  x[1] =  v[1];  x[2] =  v[2];  x[3] =  v[3];
609       x[4] =  v[4];  x[5] =  v[5];  x[6] =  v[6];  x[7] =  v[7];
610       x[8] =  v[8];  x[9] =  v[9];  x[10] = v[10]; x[11] = v[11];
611       x[12] = v[12]; x[13] = v[13]; x[14] = v[14]; x[15] = v[15];
612       x[16] = v[16]; x[17] = v[17]; x[18] = v[18]; x[19] = v[19];
613       x[20] = v[20]; x[21] = v[21]; x[22] = v[22]; x[23] = v[23];
614       x[24] = v[24]; x[25] = v[25]; x[26] = v[26]; x[27] = v[27];
615       x[28] = v[28]; x[29] = v[29]; x[30] = v[30]; x[31] = v[31];
616       x[32] = v[32]; x[33] = v[33]; x[34] = v[34]; x[35] = v[35];
617       x[36] = v[36]; x[37] = v[37]; x[38] = v[38]; x[39] = v[39];
618       x[40] = v[40]; x[41] = v[41]; x[42] = v[42]; x[43] = v[43];
619       x[44] = v[44]; x[45] = v[45]; x[46] = v[46]; x[47] = v[47];
620       x[48] = v[48];
621       v    += 49;
622     }
623     row = *ajtmp++;
624     while (row < i) {
625       pc  = rtmp + 49*row;
626       p1  = pc[0];  p2  = pc[1];  p3  = pc[2];  p4  = pc[3];
627       p5  = pc[4];  p6  = pc[5];  p7  = pc[6];  p8  = pc[7];
628       p9  = pc[8];  p10 = pc[9];  p11 = pc[10]; p12 = pc[11];
629       p13 = pc[12]; p14 = pc[13]; p15 = pc[14]; p16 = pc[15];
630       p17 = pc[16]; p18 = pc[17]; p19 = pc[18]; p20 = pc[19];
631       p21 = pc[20]; p22 = pc[21]; p23 = pc[22]; p24 = pc[23];
632       p25 = pc[24]; p26 = pc[25]; p27 = pc[26]; p28 = pc[27];
633       p29 = pc[28]; p30 = pc[29]; p31 = pc[30]; p32 = pc[31];
634       p33 = pc[32]; p34 = pc[33]; p35 = pc[34]; p36 = pc[35];
635       p37 = pc[36]; p38 = pc[37]; p39 = pc[38]; p40 = pc[39];
636       p41 = pc[40]; p42 = pc[41]; p43 = pc[42]; p44 = pc[43];
637       p45 = pc[44]; p46 = pc[45]; p47 = pc[46]; p48 = pc[47];
638       p49 = pc[48];
639       if (p1  != 0.0 || p2  != 0.0 || p3  != 0.0 || p4  != 0.0 ||
640           p5  != 0.0 || p6  != 0.0 || p7  != 0.0 || p8  != 0.0 ||
641           p9  != 0.0 || p10 != 0.0 || p11 != 0.0 || p12 != 0.0 ||
642           p13 != 0.0 || p14 != 0.0 || p15 != 0.0 || p16 != 0.0 ||
643           p17 != 0.0 || p18 != 0.0 || p19 != 0.0 || p20 != 0.0 ||
644           p21 != 0.0 || p22 != 0.0 || p23 != 0.0 || p24 != 0.0 ||
645           p25 != 0.0 || p26 != 0.0 || p27 != 0.0 || p28 != 0.0 ||
646           p29 != 0.0 || p30 != 0.0 || p31 != 0.0 || p32 != 0.0 ||
647           p33 != 0.0 || p34 != 0.0 || p35 != 0.0 || p36 != 0.0 ||
648           p37 != 0.0 || p38 != 0.0 || p39 != 0.0 || p40 != 0.0 ||
649           p41 != 0.0 || p42 != 0.0 || p43 != 0.0 || p44 != 0.0 ||
650           p45 != 0.0 || p46 != 0.0 || p47 != 0.0 || p48 != 0.0 ||
651           p49 != 0.0) {
652         pv = ba + 49*diag_offset[row];
653         pj = bj + diag_offset[row] + 1;
654 	x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
655 	x5  = pv[4];  x6  = pv[5];  x7  = pv[6];  x8  = pv[7];
656 	x9  = pv[8];  x10 = pv[9];  x11 = pv[10]; x12 = pv[11];
657 	x13 = pv[12]; x14 = pv[13]; x15 = pv[14]; x16 = pv[15];
658 	x17 = pv[16]; x18 = pv[17]; x19 = pv[18]; x20 = pv[19];
659 	x21 = pv[20]; x22 = pv[21]; x23 = pv[22]; x24 = pv[23];
660 	x25 = pv[24]; x26 = pv[25]; x27 = pv[26]; x28 = pv[27];
661 	x29 = pv[28]; x30 = pv[29]; x31 = pv[30]; x32 = pv[31];
662 	x33 = pv[32]; x34 = pv[33]; x35 = pv[34]; x36 = pv[35];
663 	x37 = pv[36]; x38 = pv[37]; x39 = pv[38]; x40 = pv[39];
664 	x41 = pv[40]; x42 = pv[41]; x43 = pv[42]; x44 = pv[43];
665 	x45 = pv[44]; x46 = pv[45]; x47 = pv[46]; x48 = pv[47];
666         x49 = pv[48];
667         pc[0]  = m1  = p1*x1  + p8*x2   + p15*x3  + p22*x4  + p29*x5  + p36*x6 + p43*x7;
668         pc[1]  = m2  = p2*x1  + p9*x2   + p16*x3  + p23*x4  + p30*x5  + p37*x6 + p44*x7;
669         pc[2]  = m3  = p3*x1  + p10*x2  + p17*x3  + p24*x4  + p31*x5  + p38*x6 + p45*x7;
670         pc[3]  = m4  = p4*x1  + p11*x2  + p18*x3  + p25*x4  + p32*x5  + p39*x6 + p46*x7;
671         pc[4]  = m5  = p5*x1  + p12*x2  + p19*x3  + p26*x4  + p33*x5  + p40*x6 + p47*x7;
672         pc[5]  = m6  = p6*x1  + p13*x2  + p20*x3  + p27*x4  + p34*x5  + p41*x6 + p48*x7;
673         pc[6]  = m7  = p7*x1  + p14*x2  + p21*x3  + p28*x4  + p35*x5  + p42*x6 + p49*x7;
674 
675         pc[7]  = m8  = p1*x8  + p8*x9   + p15*x10 + p22*x11 + p29*x12 + p36*x13 + p43*x14;
676         pc[8]  = m9  = p2*x8  + p9*x9   + p16*x10 + p23*x11 + p30*x12 + p37*x13 + p44*x14;
677         pc[9]  = m10 = p3*x8  + p10*x9  + p17*x10 + p24*x11 + p31*x12 + p38*x13 + p45*x14;
678         pc[10] = m11 = p4*x8  + p11*x9  + p18*x10 + p25*x11 + p32*x12 + p39*x13 + p46*x14;
679         pc[11] = m12 = p5*x8  + p12*x9  + p19*x10 + p26*x11 + p33*x12 + p40*x13 + p47*x14;
680         pc[12] = m13 = p6*x8  + p13*x9  + p20*x10 + p27*x11 + p34*x12 + p41*x13 + p48*x14;
681         pc[13] = m14 = p7*x8  + p14*x9  + p21*x10 + p28*x11 + p35*x12 + p42*x13 + p49*x14;
682 
683         pc[14] = m15 = p1*x15 + p8*x16  + p15*x17 + p22*x18 + p29*x19 + p36*x20 + p43*x21;
684         pc[15] = m16 = p2*x15 + p9*x16  + p16*x17 + p23*x18 + p30*x19 + p37*x20 + p44*x21;
685         pc[16] = m17 = p3*x15 + p10*x16 + p17*x17 + p24*x18 + p31*x19 + p38*x20 + p45*x21;
686         pc[17] = m18 = p4*x15 + p11*x16 + p18*x17 + p25*x18 + p32*x19 + p39*x20 + p46*x21;
687         pc[18] = m19 = p5*x15 + p12*x16 + p19*x17 + p26*x18 + p33*x19 + p40*x20 + p47*x21;
688         pc[19] = m20 = p6*x15 + p13*x16 + p20*x17 + p27*x18 + p34*x19 + p41*x20 + p48*x21;
689         pc[20] = m21 = p7*x15 + p14*x16 + p21*x17 + p28*x18 + p35*x19 + p42*x20 + p49*x21;
690 
691         pc[21] = m22 = p1*x22 + p8*x23  + p15*x24 + p22*x25 + p29*x26 + p36*x27 + p43*x28;
692         pc[22] = m23 = p2*x22 + p9*x23  + p16*x24 + p23*x25 + p30*x26 + p37*x27 + p44*x28;
693         pc[23] = m24 = p3*x22 + p10*x23 + p17*x24 + p24*x25 + p31*x26 + p38*x27 + p45*x28;
694         pc[24] = m25 = p4*x22 + p11*x23 + p18*x24 + p25*x25 + p32*x26 + p39*x27 + p46*x28;
695         pc[25] = m26 = p5*x22 + p12*x23 + p19*x24 + p26*x25 + p33*x26 + p40*x27 + p47*x28;
696         pc[26] = m27 = p6*x22 + p13*x23 + p20*x24 + p27*x25 + p34*x26 + p41*x27 + p48*x28;
697         pc[27] = m28 = p7*x22 + p14*x23 + p21*x24 + p28*x25 + p35*x26 + p42*x27 + p49*x28;
698 
699         pc[28] = m29 = p1*x29 + p8*x30  + p15*x31 + p22*x32 + p29*x33 + p36*x34 + p43*x35;
700         pc[29] = m30 = p2*x29 + p9*x30  + p16*x31 + p23*x32 + p30*x33 + p37*x34 + p44*x35;
701         pc[30] = m31 = p3*x29 + p10*x30 + p17*x31 + p24*x32 + p31*x33 + p38*x34 + p45*x35;
702         pc[31] = m32 = p4*x29 + p11*x30 + p18*x31 + p25*x32 + p32*x33 + p39*x34 + p46*x35;
703         pc[32] = m33 = p5*x29 + p12*x30 + p19*x31 + p26*x32 + p33*x33 + p40*x34 + p47*x35;
704         pc[33] = m34 = p6*x29 + p13*x30 + p20*x31 + p27*x32 + p34*x33 + p41*x34 + p48*x35;
705         pc[34] = m35 = p7*x29 + p14*x30 + p21*x31 + p28*x32 + p35*x33 + p42*x34 + p49*x35;
706 
707         pc[35] = m36 = p1*x36 + p8*x37  + p15*x38 + p22*x39 + p29*x40 + p36*x41 + p43*x42;
708         pc[36] = m37 = p2*x36 + p9*x37  + p16*x38 + p23*x39 + p30*x40 + p37*x41 + p44*x42;
709         pc[37] = m38 = p3*x36 + p10*x37 + p17*x38 + p24*x39 + p31*x40 + p38*x41 + p45*x42;
710         pc[38] = m39 = p4*x36 + p11*x37 + p18*x38 + p25*x39 + p32*x40 + p39*x41 + p46*x42;
711         pc[39] = m40 = p5*x36 + p12*x37 + p19*x38 + p26*x39 + p33*x40 + p40*x41 + p47*x42;
712         pc[40] = m41 = p6*x36 + p13*x37 + p20*x38 + p27*x39 + p34*x40 + p41*x41 + p48*x42;
713         pc[41] = m42 = p7*x36 + p14*x37 + p21*x38 + p28*x39 + p35*x40 + p42*x41 + p49*x42;
714 
715         pc[42] = m43 = p1*x43 + p8*x44  + p15*x45 + p22*x46 + p29*x47 + p36*x48 + p43*x49;
716         pc[43] = m44 = p2*x43 + p9*x44  + p16*x45 + p23*x46 + p30*x47 + p37*x48 + p44*x49;
717         pc[44] = m45 = p3*x43 + p10*x44 + p17*x45 + p24*x46 + p31*x47 + p38*x48 + p45*x49;
718         pc[45] = m46 = p4*x43 + p11*x44 + p18*x45 + p25*x46 + p32*x47 + p39*x48 + p46*x49;
719         pc[46] = m47 = p5*x43 + p12*x44 + p19*x45 + p26*x46 + p33*x47 + p40*x48 + p47*x49;
720         pc[47] = m48 = p6*x43 + p13*x44 + p20*x45 + p27*x46 + p34*x47 + p41*x48 + p48*x49;
721         pc[48] = m49 = p7*x43 + p14*x44 + p21*x45 + p28*x46 + p35*x47 + p42*x48 + p49*x49;
722 
723         nz = bi[row+1] - diag_offset[row] - 1;
724         pv += 49;
725         for (j=0; j<nz; j++) {
726 	  x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
727 	  x5  = pv[4];  x6  = pv[5];  x7  = pv[6];  x8  = pv[7];
728 	  x9  = pv[8];  x10 = pv[9];  x11 = pv[10]; x12 = pv[11];
729 	  x13 = pv[12]; x14 = pv[13]; x15 = pv[14]; x16 = pv[15];
730 	  x17 = pv[16]; x18 = pv[17]; x19 = pv[18]; x20 = pv[19];
731 	  x21 = pv[20]; x22 = pv[21]; x23 = pv[22]; x24 = pv[23];
732 	  x25 = pv[24]; x26 = pv[25]; x27 = pv[26]; x28 = pv[27];
733 	  x29 = pv[28]; x30 = pv[29]; x31 = pv[30]; x32 = pv[31];
734 	  x33 = pv[32]; x34 = pv[33]; x35 = pv[34]; x36 = pv[35];
735 	  x37 = pv[36]; x38 = pv[37]; x39 = pv[38]; x40 = pv[39];
736 	  x41 = pv[40]; x42 = pv[41]; x43 = pv[42]; x44 = pv[43];
737 	  x45 = pv[44]; x46 = pv[45]; x47 = pv[46]; x48 = pv[47];
738 	  x49 = pv[48];
739 	  x    = rtmp + 49*pj[j];
740 	  x[0]  -= m1*x1  + m8*x2   + m15*x3  + m22*x4  + m29*x5  + m36*x6 + m43*x7;
741 	  x[1]  -= m2*x1  + m9*x2   + m16*x3  + m23*x4  + m30*x5  + m37*x6 + m44*x7;
742 	  x[2]  -= m3*x1  + m10*x2  + m17*x3  + m24*x4  + m31*x5  + m38*x6 + m45*x7;
743 	  x[3]  -= m4*x1  + m11*x2  + m18*x3  + m25*x4  + m32*x5  + m39*x6 + m46*x7;
744 	  x[4]  -= m5*x1  + m12*x2  + m19*x3  + m26*x4  + m33*x5  + m40*x6 + m47*x7;
745 	  x[5]  -= m6*x1  + m13*x2  + m20*x3  + m27*x4  + m34*x5  + m41*x6 + m48*x7;
746 	  x[6]  -= m7*x1  + m14*x2  + m21*x3  + m28*x4  + m35*x5  + m42*x6 + m49*x7;
747 
748 	  x[7]  -= m1*x8  + m8*x9   + m15*x10 + m22*x11 + m29*x12 + m36*x13 + m43*x14;
749 	  x[8]  -= m2*x8  + m9*x9   + m16*x10 + m23*x11 + m30*x12 + m37*x13 + m44*x14;
750 	  x[9]  -= m3*x8  + m10*x9  + m17*x10 + m24*x11 + m31*x12 + m38*x13 + m45*x14;
751 	  x[10] -= m4*x8  + m11*x9  + m18*x10 + m25*x11 + m32*x12 + m39*x13 + m46*x14;
752 	  x[11] -= m5*x8  + m12*x9  + m19*x10 + m26*x11 + m33*x12 + m40*x13 + m47*x14;
753 	  x[12] -= m6*x8  + m13*x9  + m20*x10 + m27*x11 + m34*x12 + m41*x13 + m48*x14;
754 	  x[13] -= m7*x8  + m14*x9  + m21*x10 + m28*x11 + m35*x12 + m42*x13 + m49*x14;
755 
756 	  x[14] -= m1*x15 + m8*x16  + m15*x17 + m22*x18 + m29*x19 + m36*x20 + m43*x21;
757 	  x[15] -= m2*x15 + m9*x16  + m16*x17 + m23*x18 + m30*x19 + m37*x20 + m44*x21;
758 	  x[16] -= m3*x15 + m10*x16 + m17*x17 + m24*x18 + m31*x19 + m38*x20 + m45*x21;
759 	  x[17] -= m4*x15 + m11*x16 + m18*x17 + m25*x18 + m32*x19 + m39*x20 + m46*x21;
760 	  x[18] -= m5*x15 + m12*x16 + m19*x17 + m26*x18 + m33*x19 + m40*x20 + m47*x21;
761 	  x[19] -= m6*x15 + m13*x16 + m20*x17 + m27*x18 + m34*x19 + m41*x20 + m48*x21;
762 	  x[20] -= m7*x15 + m14*x16 + m21*x17 + m28*x18 + m35*x19 + m42*x20 + m49*x21;
763 
764 	  x[21] -= m1*x22 + m8*x23  + m15*x24 + m22*x25 + m29*x26 + m36*x27 + m43*x28;
765 	  x[22] -= m2*x22 + m9*x23  + m16*x24 + m23*x25 + m30*x26 + m37*x27 + m44*x28;
766 	  x[23] -= m3*x22 + m10*x23 + m17*x24 + m24*x25 + m31*x26 + m38*x27 + m45*x28;
767 	  x[24] -= m4*x22 + m11*x23 + m18*x24 + m25*x25 + m32*x26 + m39*x27 + m46*x28;
768 	  x[25] -= m5*x22 + m12*x23 + m19*x24 + m26*x25 + m33*x26 + m40*x27 + m47*x28;
769 	  x[26] -= m6*x22 + m13*x23 + m20*x24 + m27*x25 + m34*x26 + m41*x27 + m48*x28;
770 	  x[27] -= m7*x22 + m14*x23 + m21*x24 + m28*x25 + m35*x26 + m42*x27 + m49*x28;
771 
772 	  x[28] -= m1*x29 + m8*x30  + m15*x31 + m22*x32 + m29*x33 + m36*x34 + m43*x35;
773 	  x[29] -= m2*x29 + m9*x30  + m16*x31 + m23*x32 + m30*x33 + m37*x34 + m44*x35;
774 	  x[30] -= m3*x29 + m10*x30 + m17*x31 + m24*x32 + m31*x33 + m38*x34 + m45*x35;
775 	  x[31] -= m4*x29 + m11*x30 + m18*x31 + m25*x32 + m32*x33 + m39*x34 + m46*x35;
776 	  x[32] -= m5*x29 + m12*x30 + m19*x31 + m26*x32 + m33*x33 + m40*x34 + m47*x35;
777 	  x[33] -= m6*x29 + m13*x30 + m20*x31 + m27*x32 + m34*x33 + m41*x34 + m48*x35;
778 	  x[34] -= m7*x29 + m14*x30 + m21*x31 + m28*x32 + m35*x33 + m42*x34 + m49*x35;
779 
780 	  x[35] -= m1*x36 + m8*x37  + m15*x38 + m22*x39 + m29*x40 + m36*x41 + m43*x42;
781 	  x[36] -= m2*x36 + m9*x37  + m16*x38 + m23*x39 + m30*x40 + m37*x41 + m44*x42;
782 	  x[37] -= m3*x36 + m10*x37 + m17*x38 + m24*x39 + m31*x40 + m38*x41 + m45*x42;
783 	  x[38] -= m4*x36 + m11*x37 + m18*x38 + m25*x39 + m32*x40 + m39*x41 + m46*x42;
784 	  x[39] -= m5*x36 + m12*x37 + m19*x38 + m26*x39 + m33*x40 + m40*x41 + m47*x42;
785 	  x[40] -= m6*x36 + m13*x37 + m20*x38 + m27*x39 + m34*x40 + m41*x41 + m48*x42;
786 	  x[41] -= m7*x36 + m14*x37 + m21*x38 + m28*x39 + m35*x40 + m42*x41 + m49*x42;
787 
788 	  x[42] -= m1*x43 + m8*x44  + m15*x45 + m22*x46 + m29*x47 + m36*x48 + m43*x49;
789 	  x[43] -= m2*x43 + m9*x44  + m16*x45 + m23*x46 + m30*x47 + m37*x48 + m44*x49;
790 	  x[44] -= m3*x43 + m10*x44 + m17*x45 + m24*x46 + m31*x47 + m38*x48 + m45*x49;
791 	  x[45] -= m4*x43 + m11*x44 + m18*x45 + m25*x46 + m32*x47 + m39*x48 + m46*x49;
792 	  x[46] -= m5*x43 + m12*x44 + m19*x45 + m26*x46 + m33*x47 + m40*x48 + m47*x49;
793 	  x[47] -= m6*x43 + m13*x44 + m20*x45 + m27*x46 + m34*x47 + m41*x48 + m48*x49;
794 	  x[48] -= m7*x43 + m14*x44 + m21*x45 + m28*x46 + m35*x47 + m42*x48 + m49*x49;
795           pv   += 49;
796         }
797         PLogFlops(686*nz+637);
798       }
799       row = *ajtmp++;
800     }
801     /* finished row so stick it into b->a */
802     pv = ba + 49*bi[i];
803     pj = bj + bi[i];
804     nz = bi[i+1] - bi[i];
805     for (j=0; j<nz; j++) {
806       x      = rtmp+49*pj[j];
807       pv[0]  = x[0];  pv[1]  = x[1];  pv[2]  = x[2];  pv[3]  = x[3];
808       pv[4]  = x[4];  pv[5]  = x[5];  pv[6]  = x[6];  pv[7]  = x[7];
809       pv[8]  = x[8];  pv[9]  = x[9];  pv[10] = x[10]; pv[11] = x[11];
810       pv[12] = x[12]; pv[13] = x[13]; pv[14] = x[14]; pv[15] = x[15];
811       pv[16] = x[16]; pv[17] = x[17]; pv[18] = x[18]; pv[19] = x[19];
812       pv[20] = x[20]; pv[21] = x[21]; pv[22] = x[22]; pv[23] = x[23];
813       pv[24] = x[24]; pv[25] = x[25]; pv[26] = x[26]; pv[27] = x[27];
814       pv[28] = x[28]; pv[29] = x[29]; pv[30] = x[30]; pv[31] = x[31];
815       pv[32] = x[32]; pv[33] = x[33]; pv[34] = x[34]; pv[35] = x[35];
816       pv[36] = x[36]; pv[37] = x[37]; pv[38] = x[38]; pv[39] = x[39];
817       pv[40] = x[40]; pv[41] = x[41]; pv[42] = x[42]; pv[43] = x[43];
818       pv[44] = x[44]; pv[45] = x[45]; pv[46] = x[46]; pv[47] = x[47];
819       pv[48] = x[48];
820       pv   += 49;
821     }
822     /* invert diagonal block */
823     w = ba + 49*diag_offset[i];
824     ierr = Kernel_A_gets_inverse_A_7(w);CHKERRQ(ierr);
825   }
826 
827   ierr = PetscFree(rtmp);CHKERRQ(ierr);
828   C->factor    = FACTOR_LU;
829   C->assembled = PETSC_TRUE;
830   PLogFlops(1.3333*343*b->mbs); /* from inverting diagonal blocks */
831   PetscFunctionReturn(0);
832 }
833 
834 /* Version for when blocks are 6 by 6 */
835 #undef __FUNC__
836 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_6"
837 int MatCholeskyFactorNumeric_SeqSBAIJ_6(Mat A,Mat *B)
838 {
839   Mat                C = *B;
840   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
841   IS                 perm = b->row;
842   int                *perm_ptr,ierr,i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
843   int                *ai,*aj,*a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
844   MatScalar          *ba = b->a,*aa,*ap,*dk,*uik;
845   MatScalar          *u,*d,*w,*wp;
846 
847   PetscFunctionBegin;
848   /* initialization */
849   w  = (MatScalar*)PetscMalloc(36*mbs*sizeof(MatScalar));CHKPTRQ(w);
850   ierr = PetscMemzero(w,36*mbs*sizeof(MatScalar));CHKERRQ(ierr);
851   il = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(il);
852   jl = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(jl);
853   for (i=0; i<mbs; i++) {
854     jl[i] = mbs; il[0] = 0;
855   }
856   dk    = (MatScalar*)PetscMalloc(36*sizeof(MatScalar));CHKPTRQ(dk);
857   uik   = (MatScalar*)PetscMalloc(36*sizeof(MatScalar));CHKPTRQ(uik);
858   ierr  = ISGetIndices(perm,&perm_ptr);CHKERRQ(ierr);
859 
860   /* check permutation */
861   if (!a->permute){
862     ai = a->i; aj = a->j; aa = a->a;
863   } else {
864     ai = a->inew; aj = a->jnew;
865     aa = (MatScalar*)PetscMalloc(36*ai[mbs]*sizeof(MatScalar));CHKPTRQ(aa);
866     ierr = PetscMemcpy(aa,a->a,36*ai[mbs]*sizeof(MatScalar));CHKERRQ(ierr);
867     a2anew  = (int*)PetscMalloc(ai[mbs]*sizeof(int));CHKPTRQ(a2anew);
868     ierr= PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(int));CHKERRQ(ierr);
869 
870     for (i=0; i<mbs; i++){
871       jmin = ai[i]; jmax = ai[i+1];
872       for (j=jmin; j<jmax; j++){
873         while (a2anew[j] != j){
874           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
875           for (k1=0; k1<36; k1++){
876             dk[k1]       = aa[k*36+k1];
877             aa[k*36+k1] = aa[j*36+k1];
878             aa[j*36+k1] = dk[k1];
879           }
880         }
881         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
882         if (i > aj[j]){
883           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
884           ap = aa + j*36;                     /* ptr to the beginning of j-th block of aa */
885           for (k=0; k<36; k++) dk[k] = ap[k]; /* dk <- j-th block of aa */
886           for (k=0; k<6; k++){               /* j-th block of aa <- dk^T */
887             for (k1=0; k1<6; k1++) *ap++ = dk[k + 6*k1];
888           }
889         }
890       }
891     }
892     ierr = PetscFree(a2anew);CHKERRA(ierr);
893   }
894 
895   /* for each row k */
896   for (k = 0; k<mbs; k++){
897 
898     /*initialize k-th row with elements nonzero in row perm(k) of A */
899     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];
900     if (jmin < jmax) {
901       ap = aa + jmin*36;
902       for (j = jmin; j < jmax; j++){
903         vj = perm_ptr[aj[j]];         /* block col. index */
904         wp = w + vj*36;
905         for (i=0; i<36; i++) *wp++ = *ap++;
906       }
907     }
908 
909     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
910     ierr = PetscMemcpy(dk,w+k*36,36*sizeof(MatScalar));CHKERRQ(ierr);
911     i = jl[k]; /* first row to be added to k_th row  */
912 
913     while (i < mbs){
914       nexti = jl[i]; /* next row to be added to k_th row */
915 
916       /* compute multiplier */
917       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
918 
919       /* uik = -inv(Di)*U_bar(i,k) */
920       d = ba + i*36;
921       u    = ba + ili*36;
922 
923       uik[0] = -(d[0]*u[0] + d[6]*u[1] + d[12]*u[2] + d[18]*u[3] + d[24]*u[4] + d[30]*u[5]);
924       uik[1] = -(d[1]*u[0] + d[7]*u[1] + d[13]*u[2] + d[19]*u[3] + d[25]*u[4] + d[31]*u[5]);
925       uik[2] = -(d[2]*u[0] + d[8]*u[1] + d[14]*u[2] + d[20]*u[3] + d[26]*u[4] + d[32]*u[5]);
926       uik[3] = -(d[3]*u[0] + d[9]*u[1] + d[15]*u[2] + d[21]*u[3] + d[27]*u[4] + d[33]*u[5]);
927       uik[4] = -(d[4]*u[0]+ d[10]*u[1] + d[16]*u[2] + d[22]*u[3] + d[28]*u[4] + d[34]*u[5]);
928       uik[5] = -(d[5]*u[0]+ d[11]*u[1] + d[17]*u[2] + d[23]*u[3] + d[29]*u[4] + d[35]*u[5]);
929 
930       uik[6] = -(d[0]*u[6] + d[6]*u[7] + d[12]*u[8] + d[18]*u[9] + d[24]*u[10] + d[30]*u[11]);
931       uik[7] = -(d[1]*u[6] + d[7]*u[7] + d[13]*u[8] + d[19]*u[9] + d[25]*u[10] + d[31]*u[11]);
932       uik[8] = -(d[2]*u[6] + d[8]*u[7] + d[14]*u[8] + d[20]*u[9] + d[26]*u[10] + d[32]*u[11]);
933       uik[9] = -(d[3]*u[6] + d[9]*u[7] + d[15]*u[8] + d[21]*u[9] + d[27]*u[10] + d[33]*u[11]);
934       uik[10]= -(d[4]*u[6]+ d[10]*u[7] + d[16]*u[8] + d[22]*u[9] + d[28]*u[10] + d[34]*u[11]);
935       uik[11]= -(d[5]*u[6]+ d[11]*u[7] + d[17]*u[8] + d[23]*u[9] + d[29]*u[10] + d[35]*u[11]);
936 
937       uik[12] = -(d[0]*u[12] + d[6]*u[13] + d[12]*u[14] + d[18]*u[15] + d[24]*u[16] + d[30]*u[17]);
938       uik[13] = -(d[1]*u[12] + d[7]*u[13] + d[13]*u[14] + d[19]*u[15] + d[25]*u[16] + d[31]*u[17]);
939       uik[14] = -(d[2]*u[12] + d[8]*u[13] + d[14]*u[14] + d[20]*u[15] + d[26]*u[16] + d[32]*u[17]);
940       uik[15] = -(d[3]*u[12] + d[9]*u[13] + d[15]*u[14] + d[21]*u[15] + d[27]*u[16] + d[33]*u[17]);
941       uik[16] = -(d[4]*u[12]+ d[10]*u[13] + d[16]*u[14] + d[22]*u[15] + d[28]*u[16] + d[34]*u[17]);
942       uik[17] = -(d[5]*u[12]+ d[11]*u[13] + d[17]*u[14] + d[23]*u[15] + d[29]*u[16] + d[35]*u[17]);
943 
944       uik[18] = -(d[0]*u[18] + d[6]*u[19] + d[12]*u[20] + d[18]*u[21] + d[24]*u[22] + d[30]*u[23]);
945       uik[19] = -(d[1]*u[18] + d[7]*u[19] + d[13]*u[20] + d[19]*u[21] + d[25]*u[22] + d[31]*u[23]);
946       uik[20] = -(d[2]*u[18] + d[8]*u[19] + d[14]*u[20] + d[20]*u[21] + d[26]*u[22] + d[32]*u[23]);
947       uik[21] = -(d[3]*u[18] + d[9]*u[19] + d[15]*u[20] + d[21]*u[21] + d[27]*u[22] + d[33]*u[23]);
948       uik[22] = -(d[4]*u[18]+ d[10]*u[19] + d[16]*u[20] + d[22]*u[21] + d[28]*u[22] + d[34]*u[23]);
949       uik[23] = -(d[5]*u[18]+ d[11]*u[19] + d[17]*u[20] + d[23]*u[21] + d[29]*u[22] + d[35]*u[23]);
950 
951       uik[24] = -(d[0]*u[24] + d[6]*u[25] + d[12]*u[26] + d[18]*u[27] + d[24]*u[28] + d[30]*u[29]);
952       uik[25] = -(d[1]*u[24] + d[7]*u[25] + d[13]*u[26] + d[19]*u[27] + d[25]*u[28] + d[31]*u[29]);
953       uik[26] = -(d[2]*u[24] + d[8]*u[25] + d[14]*u[26] + d[20]*u[27] + d[26]*u[28] + d[32]*u[29]);
954       uik[27] = -(d[3]*u[24] + d[9]*u[25] + d[15]*u[26] + d[21]*u[27] + d[27]*u[28] + d[33]*u[29]);
955       uik[28] = -(d[4]*u[24]+ d[10]*u[25] + d[16]*u[26] + d[22]*u[27] + d[28]*u[28] + d[34]*u[29]);
956       uik[29] = -(d[5]*u[24]+ d[11]*u[25] + d[17]*u[26] + d[23]*u[27] + d[29]*u[28] + d[35]*u[29]);
957 
958       uik[30] = -(d[0]*u[30] + d[6]*u[31] + d[12]*u[32] + d[18]*u[33] + d[24]*u[34] + d[30]*u[35]);
959       uik[31] = -(d[1]*u[30] + d[7]*u[31] + d[13]*u[32] + d[19]*u[33] + d[25]*u[34] + d[31]*u[35]);
960       uik[32] = -(d[2]*u[30] + d[8]*u[31] + d[14]*u[32] + d[20]*u[33] + d[26]*u[34] + d[32]*u[35]);
961       uik[33] = -(d[3]*u[30] + d[9]*u[31] + d[15]*u[32] + d[21]*u[33] + d[27]*u[34] + d[33]*u[35]);
962       uik[34] = -(d[4]*u[30]+ d[10]*u[31] + d[16]*u[32] + d[22]*u[33] + d[28]*u[34] + d[34]*u[35]);
963       uik[35] = -(d[5]*u[30]+ d[11]*u[31] + d[17]*u[32] + d[23]*u[33] + d[29]*u[34] + d[35]*u[35]);
964 
965       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
966       dk[0] +=  uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3] + uik[4]*u[4] + uik[5]*u[5];
967       dk[1] +=  uik[6]*u[0] + uik[7]*u[1] + uik[8]*u[2] + uik[9]*u[3]+ uik[10]*u[4]+ uik[11]*u[5];
968       dk[2] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3]+ uik[16]*u[4]+ uik[17]*u[5];
969       dk[3] += uik[18]*u[0]+ uik[19]*u[1]+ uik[20]*u[2]+ uik[21]*u[3]+ uik[22]*u[4]+ uik[23]*u[5];
970       dk[4] += uik[24]*u[0]+ uik[25]*u[1]+ uik[26]*u[2]+ uik[27]*u[3]+ uik[28]*u[4]+ uik[29]*u[5];
971       dk[5] += uik[30]*u[0]+ uik[31]*u[1]+ uik[32]*u[2]+ uik[33]*u[3]+ uik[34]*u[4]+ uik[35]*u[5];
972 
973       dk[6] +=  uik[0]*u[6] + uik[1]*u[7] + uik[2]*u[8] + uik[3]*u[9] + uik[4]*u[10] + uik[5]*u[11];
974       dk[7] +=  uik[6]*u[6] + uik[7]*u[7] + uik[8]*u[8] + uik[9]*u[9]+ uik[10]*u[10]+ uik[11]*u[11];
975       dk[8] += uik[12]*u[6]+ uik[13]*u[7]+ uik[14]*u[8]+ uik[15]*u[9]+ uik[16]*u[10]+ uik[17]*u[11];
976       dk[9] += uik[18]*u[6]+ uik[19]*u[7]+ uik[20]*u[8]+ uik[21]*u[9]+ uik[22]*u[10]+ uik[23]*u[11];
977       dk[10]+= uik[24]*u[6]+ uik[25]*u[7]+ uik[26]*u[8]+ uik[27]*u[9]+ uik[28]*u[10]+ uik[29]*u[11];
978       dk[11]+= uik[30]*u[6]+ uik[31]*u[7]+ uik[32]*u[8]+ uik[33]*u[9]+ uik[34]*u[10]+ uik[35]*u[11];
979 
980       dk[12]+=  uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15] + uik[4]*u[16] + uik[5]*u[17];
981       dk[13]+=  uik[6]*u[12] + uik[7]*u[13] + uik[8]*u[14] + uik[9]*u[15]+ uik[10]*u[16]+ uik[11]*u[17];
982       dk[14]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15]+ uik[16]*u[16]+ uik[17]*u[17];
983       dk[15]+= uik[18]*u[12]+ uik[19]*u[13]+ uik[20]*u[14]+ uik[21]*u[15]+ uik[22]*u[16]+ uik[23]*u[17];
984       dk[16]+= uik[24]*u[12]+ uik[25]*u[13]+ uik[26]*u[14]+ uik[27]*u[15]+ uik[28]*u[16]+ uik[29]*u[17];
985       dk[17]+= uik[30]*u[12]+ uik[31]*u[13]+ uik[32]*u[14]+ uik[33]*u[15]+ uik[34]*u[16]+ uik[35]*u[17];
986 
987       dk[18]+=  uik[0]*u[18] + uik[1]*u[19] + uik[2]*u[20] + uik[3]*u[21] + uik[4]*u[22] + uik[5]*u[23];
988       dk[19]+=  uik[6]*u[18] + uik[7]*u[19] + uik[8]*u[20] + uik[9]*u[21]+ uik[10]*u[22]+ uik[11]*u[23];
989       dk[20]+= uik[12]*u[18]+ uik[13]*u[19]+ uik[14]*u[20]+ uik[15]*u[21]+ uik[16]*u[22]+ uik[17]*u[23];
990       dk[21]+= uik[18]*u[18]+ uik[19]*u[19]+ uik[20]*u[20]+ uik[21]*u[21]+ uik[22]*u[22]+ uik[23]*u[23];
991       dk[22]+= uik[24]*u[18]+ uik[25]*u[19]+ uik[26]*u[20]+ uik[27]*u[21]+ uik[28]*u[22]+ uik[29]*u[23];
992       dk[23]+= uik[30]*u[18]+ uik[31]*u[19]+ uik[32]*u[20]+ uik[33]*u[21]+ uik[34]*u[22]+ uik[35]*u[23];
993 
994       dk[24]+=  uik[0]*u[24] + uik[1]*u[25] + uik[2]*u[26] + uik[3]*u[27] + uik[4]*u[28] + uik[5]*u[29];
995       dk[25]+=  uik[6]*u[24] + uik[7]*u[25] + uik[8]*u[26] + uik[9]*u[27]+ uik[10]*u[28]+ uik[11]*u[29];
996       dk[26]+= uik[12]*u[24]+ uik[13]*u[25]+ uik[14]*u[26]+ uik[15]*u[27]+ uik[16]*u[28]+ uik[17]*u[29];
997       dk[27]+= uik[18]*u[24]+ uik[19]*u[25]+ uik[20]*u[26]+ uik[21]*u[27]+ uik[22]*u[28]+ uik[23]*u[29];
998       dk[28]+= uik[24]*u[24]+ uik[25]*u[25]+ uik[26]*u[26]+ uik[27]*u[27]+ uik[28]*u[28]+ uik[29]*u[29];
999       dk[29]+= uik[30]*u[24]+ uik[31]*u[25]+ uik[32]*u[26]+ uik[33]*u[27]+ uik[34]*u[28]+ uik[35]*u[29];
1000 
1001       dk[30]+=  uik[0]*u[30] + uik[1]*u[31] + uik[2]*u[32] + uik[3]*u[33] + uik[4]*u[34] + uik[5]*u[35];
1002       dk[31]+=  uik[6]*u[30] + uik[7]*u[31] + uik[8]*u[32] + uik[9]*u[33]+ uik[10]*u[34]+ uik[11]*u[35];
1003       dk[32]+= uik[12]*u[30]+ uik[13]*u[31]+ uik[14]*u[32]+ uik[15]*u[33]+ uik[16]*u[34]+ uik[17]*u[35];
1004       dk[33]+= uik[18]*u[30]+ uik[19]*u[31]+ uik[20]*u[32]+ uik[21]*u[33]+ uik[22]*u[34]+ uik[23]*u[35];
1005       dk[34]+= uik[24]*u[30]+ uik[25]*u[31]+ uik[26]*u[32]+ uik[27]*u[33]+ uik[28]*u[34]+ uik[29]*u[35];
1006       dk[35]+= uik[30]*u[30]+ uik[31]*u[31]+ uik[32]*u[32]+ uik[33]*u[33]+ uik[34]*u[34]+ uik[35]*u[35];
1007 
1008       /* update -U(i,k) */
1009       ierr = PetscMemcpy(ba+ili*36,uik,36*sizeof(MatScalar));CHKERRQ(ierr);
1010 
1011       /* add multiple of row i to k-th row ... */
1012       jmin = ili + 1; jmax = bi[i+1];
1013       if (jmin < jmax){
1014         for (j=jmin; j<jmax; j++) {
1015           /* w += -U(i,k)^T * U_bar(i,j) */
1016           wp = w + bj[j]*36;
1017           u = ba + j*36;
1018           wp[0] +=  uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3] + uik[4]*u[4] + uik[5]*u[5];
1019           wp[1] +=  uik[6]*u[0] + uik[7]*u[1] + uik[8]*u[2] + uik[9]*u[3]+ uik[10]*u[4]+ uik[11]*u[5];
1020           wp[2] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3]+ uik[16]*u[4]+ uik[17]*u[5];
1021           wp[3] += uik[18]*u[0]+ uik[19]*u[1]+ uik[20]*u[2]+ uik[21]*u[3]+ uik[22]*u[4]+ uik[23]*u[5];
1022           wp[4] += uik[24]*u[0]+ uik[25]*u[1]+ uik[26]*u[2]+ uik[27]*u[3]+ uik[28]*u[4]+ uik[29]*u[5];
1023           wp[5] += uik[30]*u[0]+ uik[31]*u[1]+ uik[32]*u[2]+ uik[33]*u[3]+ uik[34]*u[4]+ uik[35]*u[5];
1024 
1025           wp[6] +=  uik[0]*u[6] + uik[1]*u[7] + uik[2]*u[8] + uik[3]*u[9] + uik[4]*u[10] + uik[5]*u[11];
1026           wp[7] +=  uik[6]*u[6] + uik[7]*u[7] + uik[8]*u[8] + uik[9]*u[9]+ uik[10]*u[10]+ uik[11]*u[11];
1027           wp[8] += uik[12]*u[6]+ uik[13]*u[7]+ uik[14]*u[8]+ uik[15]*u[9]+ uik[16]*u[10]+ uik[17]*u[11];
1028           wp[9] += uik[18]*u[6]+ uik[19]*u[7]+ uik[20]*u[8]+ uik[21]*u[9]+ uik[22]*u[10]+ uik[23]*u[11];
1029           wp[10]+= uik[24]*u[6]+ uik[25]*u[7]+ uik[26]*u[8]+ uik[27]*u[9]+ uik[28]*u[10]+ uik[29]*u[11];
1030           wp[11]+= uik[30]*u[6]+ uik[31]*u[7]+ uik[32]*u[8]+ uik[33]*u[9]+ uik[34]*u[10]+ uik[35]*u[11];
1031 
1032           wp[12]+=  uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15] + uik[4]*u[16] + uik[5]*u[17];
1033           wp[13]+=  uik[6]*u[12] + uik[7]*u[13] + uik[8]*u[14] + uik[9]*u[15]+ uik[10]*u[16]+ uik[11]*u[17];
1034           wp[14]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15]+ uik[16]*u[16]+ uik[17]*u[17];
1035           wp[15]+= uik[18]*u[12]+ uik[19]*u[13]+ uik[20]*u[14]+ uik[21]*u[15]+ uik[22]*u[16]+ uik[23]*u[17];
1036           wp[16]+= uik[24]*u[12]+ uik[25]*u[13]+ uik[26]*u[14]+ uik[27]*u[15]+ uik[28]*u[16]+ uik[29]*u[17];
1037           wp[17]+= uik[30]*u[12]+ uik[31]*u[13]+ uik[32]*u[14]+ uik[33]*u[15]+ uik[34]*u[16]+ uik[35]*u[17];
1038 
1039           wp[18]+=  uik[0]*u[18] + uik[1]*u[19] + uik[2]*u[20] + uik[3]*u[21] + uik[4]*u[22] + uik[5]*u[23];
1040           wp[19]+=  uik[6]*u[18] + uik[7]*u[19] + uik[8]*u[20] + uik[9]*u[21]+ uik[10]*u[22]+ uik[11]*u[23];
1041           wp[20]+= uik[12]*u[18]+ uik[13]*u[19]+ uik[14]*u[20]+ uik[15]*u[21]+ uik[16]*u[22]+ uik[17]*u[23];
1042           wp[21]+= uik[18]*u[18]+ uik[19]*u[19]+ uik[20]*u[20]+ uik[21]*u[21]+ uik[22]*u[22]+ uik[23]*u[23];
1043           wp[22]+= uik[24]*u[18]+ uik[25]*u[19]+ uik[26]*u[20]+ uik[27]*u[21]+ uik[28]*u[22]+ uik[29]*u[23];
1044           wp[23]+= uik[30]*u[18]+ uik[31]*u[19]+ uik[32]*u[20]+ uik[33]*u[21]+ uik[34]*u[22]+ uik[35]*u[23];
1045 
1046           wp[24]+=  uik[0]*u[24] + uik[1]*u[25] + uik[2]*u[26] + uik[3]*u[27] + uik[4]*u[28] + uik[5]*u[29];
1047           wp[25]+=  uik[6]*u[24] + uik[7]*u[25] + uik[8]*u[26] + uik[9]*u[27]+ uik[10]*u[28]+ uik[11]*u[29];
1048           wp[26]+= uik[12]*u[24]+ uik[13]*u[25]+ uik[14]*u[26]+ uik[15]*u[27]+ uik[16]*u[28]+ uik[17]*u[29];
1049           wp[27]+= uik[18]*u[24]+ uik[19]*u[25]+ uik[20]*u[26]+ uik[21]*u[27]+ uik[22]*u[28]+ uik[23]*u[29];
1050           wp[28]+= uik[24]*u[24]+ uik[25]*u[25]+ uik[26]*u[26]+ uik[27]*u[27]+ uik[28]*u[28]+ uik[29]*u[29];
1051           wp[29]+= uik[30]*u[24]+ uik[31]*u[25]+ uik[32]*u[26]+ uik[33]*u[27]+ uik[34]*u[28]+ uik[35]*u[29];
1052 
1053           wp[30]+=  uik[0]*u[30] + uik[1]*u[31] + uik[2]*u[32] + uik[3]*u[33] + uik[4]*u[34] + uik[5]*u[35];
1054           wp[31]+=  uik[6]*u[30] + uik[7]*u[31] + uik[8]*u[32] + uik[9]*u[33]+ uik[10]*u[34]+ uik[11]*u[35];
1055           wp[32]+= uik[12]*u[30]+ uik[13]*u[31]+ uik[14]*u[32]+ uik[15]*u[33]+ uik[16]*u[34]+ uik[17]*u[35];
1056           wp[33]+= uik[18]*u[30]+ uik[19]*u[31]+ uik[20]*u[32]+ uik[21]*u[33]+ uik[22]*u[34]+ uik[23]*u[35];
1057           wp[34]+= uik[24]*u[30]+ uik[25]*u[31]+ uik[26]*u[32]+ uik[27]*u[33]+ uik[28]*u[34]+ uik[29]*u[35];
1058           wp[35]+= uik[30]*u[30]+ uik[31]*u[31]+ uik[32]*u[32]+ uik[33]*u[33]+ uik[34]*u[34]+ uik[35]*u[35];
1059         }
1060 
1061         /* ... add i to row list for next nonzero entry */
1062         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
1063         j     = bj[jmin];
1064         jl[i] = jl[j]; jl[j] = i; /* update jl */
1065       }
1066       i = nexti;
1067     }
1068 
1069     /* save nonzero entries in k-th row of U ... */
1070 
1071     /* invert diagonal block */
1072     d = ba+k*36;
1073     ierr = PetscMemcpy(d,dk,36*sizeof(MatScalar));CHKERRQ(ierr);
1074     ierr = Kernel_A_gets_inverse_A_6(d);CHKERRQ(ierr);
1075 
1076     jmin = bi[k]; jmax = bi[k+1];
1077     if (jmin < jmax) {
1078       for (j=jmin; j<jmax; j++){
1079          vj = bj[j];           /* block col. index of U */
1080          u   = ba + j*36;
1081          wp = w + vj*36;
1082          for (k1=0; k1<36; k1++){
1083            *u++        = *wp;
1084            *wp++ = 0.0;
1085          }
1086       }
1087 
1088       /* ... add k to row list for first nonzero entry in k-th row */
1089       il[k] = jmin;
1090       i     = bj[jmin];
1091       jl[k] = jl[i]; jl[i] = k;
1092     }
1093   }
1094 
1095   ierr = PetscFree(w);CHKERRQ(ierr);
1096   ierr = PetscFree(il);CHKERRQ(ierr);
1097   ierr = PetscFree(jl);CHKERRQ(ierr);
1098   ierr = PetscFree(dk);CHKERRQ(ierr);
1099   ierr = PetscFree(uik);CHKERRQ(ierr);
1100   if (a->permute){
1101     ierr = PetscFree(aa);CHKERRQ(ierr);
1102   }
1103 
1104   ierr = ISRestoreIndices(perm,&perm_ptr);CHKERRQ(ierr);
1105   C->factor    = FACTOR_CHOLESKY;
1106   C->assembled = PETSC_TRUE;
1107   C->preallocated = PETSC_TRUE;
1108   PLogFlops(1.3333*216*b->mbs); /* from inverting diagonal blocks */
1109   PetscFunctionReturn(0);
1110 }
1111 
1112 /*
1113       Version for when blocks are 6 by 6 Using natural ordering
1114 */
1115 #undef __FUNC__
1116 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_6_NaturalOrdering"
1117 int MatCholeskyFactorNumeric_SeqSBAIJ_6_NaturalOrdering(Mat A,Mat *B)
1118 {
1119   Mat         C = *B;
1120   Mat_SeqBAIJ *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
1121   int         ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
1122   int         *ajtmpold,*ajtmp,nz,row;
1123   int         *diag_offset = b->diag,*ai=a->i,*aj=a->j,*pj;
1124   MatScalar   *pv,*v,*rtmp,*pc,*w,*x;
1125   MatScalar   x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15;
1126   MatScalar   x16,x17,x18,x19,x20,x21,x22,x23,x24,x25;
1127   MatScalar   p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12,p13,p14,p15;
1128   MatScalar   p16,p17,p18,p19,p20,p21,p22,p23,p24,p25;
1129   MatScalar   m1,m2,m3,m4,m5,m6,m7,m8,m9,m10,m11,m12,m13,m14,m15;
1130   MatScalar   m16,m17,m18,m19,m20,m21,m22,m23,m24,m25;
1131   MatScalar   p26,p27,p28,p29,p30,p31,p32,p33,p34,p35,p36;
1132   MatScalar   x26,x27,x28,x29,x30,x31,x32,x33,x34,x35,x36;
1133   MatScalar   m26,m27,m28,m29,m30,m31,m32,m33,m34,m35,m36;
1134   MatScalar   *ba = b->a,*aa = a->a;
1135 
1136   PetscFunctionBegin;
1137   rtmp  = (MatScalar*)PetscMalloc(36*(n+1)*sizeof(MatScalar));CHKPTRQ(rtmp);
1138   for (i=0; i<n; i++) {
1139     nz    = bi[i+1] - bi[i];
1140     ajtmp = bj + bi[i];
1141     for  (j=0; j<nz; j++) {
1142       x = rtmp+36*ajtmp[j];
1143       x[0] = x[1] = x[2] = x[3] = x[4] = x[5] = x[6] = x[7] = x[8] = x[9] = 0.0;
1144       x[10] = x[11] = x[12] = x[13] = x[14] = x[15] = x[16] = x[17] = 0.0;
1145       x[18] = x[19] = x[20] = x[21] = x[22] = x[23] = x[24] = x[25] = 0.0 ;
1146       x[26] = x[27] = x[28] = x[29] = x[30] = x[31] = x[32] = x[33] = 0.0 ;
1147       x[34] = x[35] = 0.0 ;
1148     }
1149     /* load in initial (unfactored row) */
1150     nz       = ai[i+1] - ai[i];
1151     ajtmpold = aj + ai[i];
1152     v        = aa + 36*ai[i];
1153     for (j=0; j<nz; j++) {
1154       x    = rtmp+36*ajtmpold[j];
1155       x[0] =  v[0];  x[1] =  v[1];  x[2] =  v[2];  x[3] =  v[3];
1156       x[4] =  v[4];  x[5] =  v[5];  x[6] =  v[6];  x[7] =  v[7];
1157       x[8] =  v[8];  x[9] =  v[9];  x[10] = v[10]; x[11] = v[11];
1158       x[12] = v[12]; x[13] = v[13]; x[14] = v[14]; x[15] = v[15];
1159       x[16] = v[16]; x[17] = v[17]; x[18] = v[18]; x[19] = v[19];
1160       x[20] = v[20]; x[21] = v[21]; x[22] = v[22]; x[23] = v[23];
1161       x[24] = v[24]; x[25] = v[25]; x[26] = v[26]; x[27] = v[27];
1162       x[28] = v[28]; x[29] = v[29]; x[30] = v[30]; x[31] = v[31];
1163       x[32] = v[32]; x[33] = v[33]; x[34] = v[34]; x[35] = v[35];
1164       v    += 36;
1165     }
1166     row = *ajtmp++;
1167     while (row < i) {
1168       pc  = rtmp + 36*row;
1169       p1  = pc[0];  p2  = pc[1];  p3  = pc[2];  p4  = pc[3];
1170       p5  = pc[4];  p6  = pc[5];  p7  = pc[6];  p8  = pc[7];
1171       p9  = pc[8];  p10 = pc[9];  p11 = pc[10]; p12 = pc[11];
1172       p13 = pc[12]; p14 = pc[13]; p15 = pc[14]; p16 = pc[15];
1173       p17 = pc[16]; p18 = pc[17]; p19 = pc[18]; p20 = pc[19];
1174       p21 = pc[20]; p22 = pc[21]; p23 = pc[22]; p24 = pc[23];
1175       p25 = pc[24]; p26 = pc[25]; p27 = pc[26]; p28 = pc[27];
1176       p29 = pc[28]; p30 = pc[29]; p31 = pc[30]; p32 = pc[31];
1177       p33 = pc[32]; p34 = pc[33]; p35 = pc[34]; p36 = pc[35];
1178       if (p1  != 0.0 || p2  != 0.0 || p3  != 0.0 || p4  != 0.0 ||
1179           p5  != 0.0 || p6  != 0.0 || p7  != 0.0 || p8  != 0.0 ||
1180           p9  != 0.0 || p10 != 0.0 || p11 != 0.0 || p12 != 0.0 ||
1181           p13 != 0.0 || p14 != 0.0 || p15 != 0.0 || p16 != 0.0 ||
1182           p17 != 0.0 || p18 != 0.0 || p19 != 0.0 || p20 != 0.0 ||
1183           p21 != 0.0 || p22 != 0.0 || p23 != 0.0 || p24 != 0.0 ||
1184           p25 != 0.0 || p26 != 0.0 || p27 != 0.0 || p28 != 0.0 ||
1185           p29 != 0.0 || p30 != 0.0 || p31 != 0.0 || p32 != 0.0 ||
1186           p33 != 0.0 || p34 != 0.0 || p35 != 0.0 || p36 != 0.0) {
1187         pv = ba + 36*diag_offset[row];
1188         pj = bj + diag_offset[row] + 1;
1189 	x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
1190 	x5  = pv[4];  x6  = pv[5];  x7  = pv[6];  x8  = pv[7];
1191 	x9  = pv[8];  x10 = pv[9];  x11 = pv[10]; x12 = pv[11];
1192 	x13 = pv[12]; x14 = pv[13]; x15 = pv[14]; x16 = pv[15];
1193 	x17 = pv[16]; x18 = pv[17]; x19 = pv[18]; x20 = pv[19];
1194 	x21 = pv[20]; x22 = pv[21]; x23 = pv[22]; x24 = pv[23];
1195 	x25 = pv[24]; x26 = pv[25]; x27 = pv[26]; x28 = pv[27];
1196 	x29 = pv[28]; x30 = pv[29]; x31 = pv[30]; x32 = pv[31];
1197 	x33 = pv[32]; x34 = pv[33]; x35 = pv[34]; x36 = pv[35];
1198         pc[0]  = m1  = p1*x1  + p7*x2   + p13*x3  + p19*x4  + p25*x5  + p31*x6;
1199         pc[1]  = m2  = p2*x1  + p8*x2   + p14*x3  + p20*x4  + p26*x5  + p32*x6;
1200         pc[2]  = m3  = p3*x1  + p9*x2   + p15*x3  + p21*x4  + p27*x5  + p33*x6;
1201         pc[3]  = m4  = p4*x1  + p10*x2  + p16*x3  + p22*x4  + p28*x5  + p34*x6;
1202         pc[4]  = m5  = p5*x1  + p11*x2  + p17*x3  + p23*x4  + p29*x5  + p35*x6;
1203         pc[5]  = m6  = p6*x1  + p12*x2  + p18*x3  + p24*x4  + p30*x5  + p36*x6;
1204 
1205         pc[6]  = m7  = p1*x7  + p7*x8   + p13*x9  + p19*x10 + p25*x11 + p31*x12;
1206         pc[7]  = m8  = p2*x7  + p8*x8   + p14*x9  + p20*x10 + p26*x11 + p32*x12;
1207         pc[8]  = m9  = p3*x7  + p9*x8   + p15*x9  + p21*x10 + p27*x11 + p33*x12;
1208         pc[9]  = m10 = p4*x7  + p10*x8  + p16*x9  + p22*x10 + p28*x11 + p34*x12;
1209         pc[10] = m11 = p5*x7  + p11*x8  + p17*x9  + p23*x10 + p29*x11 + p35*x12;
1210         pc[11] = m12 = p6*x7  + p12*x8  + p18*x9  + p24*x10 + p30*x11 + p36*x12;
1211 
1212         pc[12] = m13 = p1*x13 + p7*x14  + p13*x15 + p19*x16 + p25*x17 + p31*x18;
1213         pc[13] = m14 = p2*x13 + p8*x14  + p14*x15 + p20*x16 + p26*x17 + p32*x18;
1214         pc[14] = m15 = p3*x13 + p9*x14  + p15*x15 + p21*x16 + p27*x17 + p33*x18;
1215         pc[15] = m16 = p4*x13 + p10*x14 + p16*x15 + p22*x16 + p28*x17 + p34*x18;
1216         pc[16] = m17 = p5*x13 + p11*x14 + p17*x15 + p23*x16 + p29*x17 + p35*x18;
1217         pc[17] = m18 = p6*x13 + p12*x14 + p18*x15 + p24*x16 + p30*x17 + p36*x18;
1218 
1219         pc[18] = m19 = p1*x19 + p7*x20  + p13*x21 + p19*x22 + p25*x23 + p31*x24;
1220         pc[19] = m20 = p2*x19 + p8*x20  + p14*x21 + p20*x22 + p26*x23 + p32*x24;
1221         pc[20] = m21 = p3*x19 + p9*x20  + p15*x21 + p21*x22 + p27*x23 + p33*x24;
1222         pc[21] = m22 = p4*x19 + p10*x20 + p16*x21 + p22*x22 + p28*x23 + p34*x24;
1223         pc[22] = m23 = p5*x19 + p11*x20 + p17*x21 + p23*x22 + p29*x23 + p35*x24;
1224         pc[23] = m24 = p6*x19 + p12*x20 + p18*x21 + p24*x22 + p30*x23 + p36*x24;
1225 
1226         pc[24] = m25 = p1*x25 + p7*x26  + p13*x27 + p19*x28 + p25*x29 + p31*x30;
1227         pc[25] = m26 = p2*x25 + p8*x26  + p14*x27 + p20*x28 + p26*x29 + p32*x30;
1228         pc[26] = m27 = p3*x25 + p9*x26  + p15*x27 + p21*x28 + p27*x29 + p33*x30;
1229         pc[27] = m28 = p4*x25 + p10*x26 + p16*x27 + p22*x28 + p28*x29 + p34*x30;
1230         pc[28] = m29 = p5*x25 + p11*x26 + p17*x27 + p23*x28 + p29*x29 + p35*x30;
1231         pc[29] = m30 = p6*x25 + p12*x26 + p18*x27 + p24*x28 + p30*x29 + p36*x30;
1232 
1233         pc[30] = m31 = p1*x31 + p7*x32  + p13*x33 + p19*x34 + p25*x35 + p31*x36;
1234         pc[31] = m32 = p2*x31 + p8*x32  + p14*x33 + p20*x34 + p26*x35 + p32*x36;
1235         pc[32] = m33 = p3*x31 + p9*x32  + p15*x33 + p21*x34 + p27*x35 + p33*x36;
1236         pc[33] = m34 = p4*x31 + p10*x32 + p16*x33 + p22*x34 + p28*x35 + p34*x36;
1237         pc[34] = m35 = p5*x31 + p11*x32 + p17*x33 + p23*x34 + p29*x35 + p35*x36;
1238         pc[35] = m36 = p6*x31 + p12*x32 + p18*x33 + p24*x34 + p30*x35 + p36*x36;
1239 
1240         nz = bi[row+1] - diag_offset[row] - 1;
1241         pv += 36;
1242         for (j=0; j<nz; j++) {
1243 	  x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
1244 	  x5  = pv[4];  x6  = pv[5];  x7  = pv[6];  x8  = pv[7];
1245 	  x9  = pv[8];  x10 = pv[9];  x11 = pv[10]; x12 = pv[11];
1246 	  x13 = pv[12]; x14 = pv[13]; x15 = pv[14]; x16 = pv[15];
1247 	  x17 = pv[16]; x18 = pv[17]; x19 = pv[18]; x20 = pv[19];
1248 	  x21 = pv[20]; x22 = pv[21]; x23 = pv[22]; x24 = pv[23];
1249 	  x25 = pv[24]; x26 = pv[25]; x27 = pv[26]; x28 = pv[27];
1250 	  x29 = pv[28]; x30 = pv[29]; x31 = pv[30]; x32 = pv[31];
1251 	  x33 = pv[32]; x34 = pv[33]; x35 = pv[34]; x36 = pv[35];
1252 	  x    = rtmp + 36*pj[j];
1253           x[0]  -= m1*x1  + m7*x2   + m13*x3  + m19*x4  + m25*x5  + m31*x6;
1254           x[1]  -= m2*x1  + m8*x2   + m14*x3  + m20*x4  + m26*x5  + m32*x6;
1255           x[2]  -= m3*x1  + m9*x2   + m15*x3  + m21*x4  + m27*x5  + m33*x6;
1256           x[3]  -= m4*x1  + m10*x2  + m16*x3  + m22*x4  + m28*x5  + m34*x6;
1257           x[4]  -= m5*x1  + m11*x2  + m17*x3  + m23*x4  + m29*x5  + m35*x6;
1258           x[5]  -= m6*x1  + m12*x2  + m18*x3  + m24*x4  + m30*x5  + m36*x6;
1259 
1260 	  x[6]  -= m1*x7  + m7*x8   + m13*x9  + m19*x10 + m25*x11 + m31*x12;
1261 	  x[7]  -= m2*x7  + m8*x8   + m14*x9  + m20*x10 + m26*x11 + m32*x12;
1262 	  x[8]  -= m3*x7  + m9*x8   + m15*x9  + m21*x10 + m27*x11 + m33*x12;
1263 	  x[9]  -= m4*x7  + m10*x8  + m16*x9  + m22*x10 + m28*x11 + m34*x12;
1264 	  x[10] -= m5*x7  + m11*x8  + m17*x9  + m23*x10 + m29*x11 + m35*x12;
1265 	  x[11] -= m6*x7  + m12*x8  + m18*x9  + m24*x10 + m30*x11 + m36*x12;
1266 
1267 	  x[12] -= m1*x13 + m7*x14  + m13*x15 + m19*x16 + m25*x17 + m31*x18;
1268 	  x[13] -= m2*x13 + m8*x14  + m14*x15 + m20*x16 + m26*x17 + m32*x18;
1269 	  x[14] -= m3*x13 + m9*x14  + m15*x15 + m21*x16 + m27*x17 + m33*x18;
1270 	  x[15] -= m4*x13 + m10*x14 + m16*x15 + m22*x16 + m28*x17 + m34*x18;
1271 	  x[16] -= m5*x13 + m11*x14 + m17*x15 + m23*x16 + m29*x17 + m35*x18;
1272 	  x[17] -= m6*x13 + m12*x14 + m18*x15 + m24*x16 + m30*x17 + m36*x18;
1273 
1274 	  x[18] -= m1*x19 + m7*x20  + m13*x21 + m19*x22 + m25*x23 + m31*x24;
1275 	  x[19] -= m2*x19 + m8*x20  + m14*x21 + m20*x22 + m26*x23 + m32*x24;
1276 	  x[20] -= m3*x19 + m9*x20  + m15*x21 + m21*x22 + m27*x23 + m33*x24;
1277 	  x[21] -= m4*x19 + m10*x20 + m16*x21 + m22*x22 + m28*x23 + m34*x24;
1278 	  x[22] -= m5*x19 + m11*x20 + m17*x21 + m23*x22 + m29*x23 + m35*x24;
1279 	  x[23] -= m6*x19 + m12*x20 + m18*x21 + m24*x22 + m30*x23 + m36*x24;
1280 
1281 	  x[24] -= m1*x25 + m7*x26  + m13*x27 + m19*x28 + m25*x29 + m31*x30;
1282 	  x[25] -= m2*x25 + m8*x26  + m14*x27 + m20*x28 + m26*x29 + m32*x30;
1283 	  x[26] -= m3*x25 + m9*x26  + m15*x27 + m21*x28 + m27*x29 + m33*x30;
1284 	  x[27] -= m4*x25 + m10*x26 + m16*x27 + m22*x28 + m28*x29 + m34*x30;
1285 	  x[28] -= m5*x25 + m11*x26 + m17*x27 + m23*x28 + m29*x29 + m35*x30;
1286 	  x[29] -= m6*x25 + m12*x26 + m18*x27 + m24*x28 + m30*x29 + m36*x30;
1287 
1288 	  x[30] -= m1*x31 + m7*x32  + m13*x33 + m19*x34 + m25*x35 + m31*x36;
1289 	  x[31] -= m2*x31 + m8*x32  + m14*x33 + m20*x34 + m26*x35 + m32*x36;
1290 	  x[32] -= m3*x31 + m9*x32  + m15*x33 + m21*x34 + m27*x35 + m33*x36;
1291 	  x[33] -= m4*x31 + m10*x32 + m16*x33 + m22*x34 + m28*x35 + m34*x36;
1292 	  x[34] -= m5*x31 + m11*x32 + m17*x33 + m23*x34 + m29*x35 + m35*x36;
1293 	  x[35] -= m6*x31 + m12*x32 + m18*x33 + m24*x34 + m30*x35 + m36*x36;
1294 
1295           pv   += 36;
1296         }
1297         PLogFlops(432*nz+396);
1298       }
1299       row = *ajtmp++;
1300     }
1301     /* finished row so stick it into b->a */
1302     pv = ba + 36*bi[i];
1303     pj = bj + bi[i];
1304     nz = bi[i+1] - bi[i];
1305     for (j=0; j<nz; j++) {
1306       x      = rtmp+36*pj[j];
1307       pv[0]  = x[0];  pv[1]  = x[1];  pv[2]  = x[2];  pv[3]  = x[3];
1308       pv[4]  = x[4];  pv[5]  = x[5];  pv[6]  = x[6];  pv[7]  = x[7];
1309       pv[8]  = x[8];  pv[9]  = x[9];  pv[10] = x[10]; pv[11] = x[11];
1310       pv[12] = x[12]; pv[13] = x[13]; pv[14] = x[14]; pv[15] = x[15];
1311       pv[16] = x[16]; pv[17] = x[17]; pv[18] = x[18]; pv[19] = x[19];
1312       pv[20] = x[20]; pv[21] = x[21]; pv[22] = x[22]; pv[23] = x[23];
1313       pv[24] = x[24]; pv[25] = x[25]; pv[26] = x[26]; pv[27] = x[27];
1314       pv[28] = x[28]; pv[29] = x[29]; pv[30] = x[30]; pv[31] = x[31];
1315       pv[32] = x[32]; pv[33] = x[33]; pv[34] = x[34]; pv[35] = x[35];
1316       pv   += 36;
1317     }
1318     /* invert diagonal block */
1319     w = ba + 36*diag_offset[i];
1320     ierr = Kernel_A_gets_inverse_A_6(w);CHKERRQ(ierr);
1321   }
1322 
1323   ierr = PetscFree(rtmp);CHKERRQ(ierr);
1324   C->factor    = FACTOR_LU;
1325   C->assembled = PETSC_TRUE;
1326   PLogFlops(1.3333*216*b->mbs); /* from inverting diagonal blocks */
1327   PetscFunctionReturn(0);
1328 }
1329 
1330 /* Version for when blocks are 5 by 5  */
1331 #undef __FUNC__
1332 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_5"
1333 int MatCholeskyFactorNumeric_SeqSBAIJ_5(Mat A,Mat *B)
1334 {
1335   Mat                C = *B;
1336   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
1337   IS                 perm = b->row;
1338   int                *perm_ptr,ierr,i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
1339   int                *ai,*aj,*a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
1340   MatScalar          *ba = b->a,*aa,*ap,*dk,*uik;
1341   MatScalar          *u,*d,*rtmp,*rtmp_ptr;
1342 
1343   PetscFunctionBegin;
1344   /* initialization */
1345   rtmp  = (MatScalar*)PetscMalloc(25*mbs*sizeof(MatScalar));CHKPTRQ(rtmp);
1346   ierr = PetscMemzero(rtmp,25*mbs*sizeof(MatScalar));CHKERRQ(ierr);
1347   il = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(il);
1348   jl = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(jl);
1349   for (i=0; i<mbs; i++) {
1350     jl[i] = mbs; il[0] = 0;
1351   }
1352   dk    = (MatScalar*)PetscMalloc(25*sizeof(MatScalar));CHKPTRQ(dk);
1353   uik   = (MatScalar*)PetscMalloc(25*sizeof(MatScalar));CHKPTRQ(uik);
1354   ierr  = ISGetIndices(perm,&perm_ptr);CHKERRQ(ierr);
1355 
1356   /* check permutation */
1357   if (!a->permute){
1358     ai = a->i; aj = a->j; aa = a->a;
1359   } else {
1360     ai = a->inew; aj = a->jnew;
1361     aa = (MatScalar*)PetscMalloc(25*ai[mbs]*sizeof(MatScalar));CHKPTRQ(aa);
1362     ierr = PetscMemcpy(aa,a->a,25*ai[mbs]*sizeof(MatScalar));CHKERRQ(ierr);
1363     a2anew  = (int*)PetscMalloc(ai[mbs]*sizeof(int));CHKPTRQ(a2anew);
1364     ierr= PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(int));CHKERRQ(ierr);
1365 
1366     for (i=0; i<mbs; i++){
1367       jmin = ai[i]; jmax = ai[i+1];
1368       for (j=jmin; j<jmax; j++){
1369         while (a2anew[j] != j){
1370           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
1371           for (k1=0; k1<25; k1++){
1372             dk[k1]       = aa[k*25+k1];
1373             aa[k*25+k1] = aa[j*25+k1];
1374             aa[j*25+k1] = dk[k1];
1375           }
1376         }
1377         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
1378         if (i > aj[j]){
1379           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
1380           ap = aa + j*25;                     /* ptr to the beginning of j-th block of aa */
1381           for (k=0; k<25; k++) dk[k] = ap[k]; /* dk <- j-th block of aa */
1382           for (k=0; k<5; k++){               /* j-th block of aa <- dk^T */
1383             for (k1=0; k1<5; k1++) *ap++ = dk[k + 5*k1];
1384           }
1385         }
1386       }
1387     }
1388     ierr = PetscFree(a2anew);CHKERRA(ierr);
1389   }
1390 
1391   /* for each row k */
1392   for (k = 0; k<mbs; k++){
1393 
1394     /*initialize k-th row with elements nonzero in row perm(k) of A */
1395     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];
1396     if (jmin < jmax) {
1397       ap = aa + jmin*25;
1398       for (j = jmin; j < jmax; j++){
1399         vj = perm_ptr[aj[j]];         /* block col. index */
1400         rtmp_ptr = rtmp + vj*25;
1401         for (i=0; i<25; i++) *rtmp_ptr++ = *ap++;
1402       }
1403     }
1404 
1405     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
1406     ierr = PetscMemcpy(dk,rtmp+k*25,25*sizeof(MatScalar));CHKERRQ(ierr);
1407     i = jl[k]; /* first row to be added to k_th row  */
1408 
1409     while (i < mbs){
1410       nexti = jl[i]; /* next row to be added to k_th row */
1411 
1412       /* compute multiplier */
1413       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
1414 
1415       /* uik = -inv(Di)*U_bar(i,k) */
1416       d = ba + i*25;
1417       u    = ba + ili*25;
1418 
1419       uik[0] = -(d[0]*u[0] + d[5]*u[1] + d[10]*u[2] + d[15]*u[3] + d[20]*u[4]);
1420       uik[1] = -(d[1]*u[0] + d[6]*u[1] + d[11]*u[2] + d[16]*u[3] + d[21]*u[4]);
1421       uik[2] = -(d[2]*u[0] + d[7]*u[1] + d[12]*u[2] + d[17]*u[3] + d[22]*u[4]);
1422       uik[3] = -(d[3]*u[0] + d[8]*u[1] + d[13]*u[2] + d[18]*u[3] + d[23]*u[4]);
1423       uik[4] = -(d[4]*u[0] + d[9]*u[1] + d[14]*u[2] + d[19]*u[3] + d[24]*u[4]);
1424 
1425       uik[5] = -(d[0]*u[5] + d[5]*u[6] + d[10]*u[7] + d[15]*u[8] + d[20]*u[9]);
1426       uik[6] = -(d[1]*u[5] + d[6]*u[6] + d[11]*u[7] + d[16]*u[8] + d[21]*u[9]);
1427       uik[7] = -(d[2]*u[5] + d[7]*u[6] + d[12]*u[7] + d[17]*u[8] + d[22]*u[9]);
1428       uik[8] = -(d[3]*u[5] + d[8]*u[6] + d[13]*u[7] + d[18]*u[8] + d[23]*u[9]);
1429       uik[9] = -(d[4]*u[5] + d[9]*u[6] + d[14]*u[7] + d[19]*u[8] + d[24]*u[9]);
1430 
1431       uik[10]= -(d[0]*u[10] + d[5]*u[11] + d[10]*u[12] + d[15]*u[13] + d[20]*u[14]);
1432       uik[11]= -(d[1]*u[10] + d[6]*u[11] + d[11]*u[12] + d[16]*u[13] + d[21]*u[14]);
1433       uik[12]= -(d[2]*u[10] + d[7]*u[11] + d[12]*u[12] + d[17]*u[13] + d[22]*u[14]);
1434       uik[13]= -(d[3]*u[10] + d[8]*u[11] + d[13]*u[12] + d[18]*u[13] + d[23]*u[14]);
1435       uik[14]= -(d[4]*u[10] + d[9]*u[11] + d[14]*u[12] + d[19]*u[13] + d[24]*u[14]);
1436 
1437       uik[15]= -(d[0]*u[15] + d[5]*u[16] + d[10]*u[17] + d[15]*u[18] + d[20]*u[19]);
1438       uik[16]= -(d[1]*u[15] + d[6]*u[16] + d[11]*u[17] + d[16]*u[18] + d[21]*u[19]);
1439       uik[17]= -(d[2]*u[15] + d[7]*u[16] + d[12]*u[17] + d[17]*u[18] + d[22]*u[19]);
1440       uik[18]= -(d[3]*u[15] + d[8]*u[16] + d[13]*u[17] + d[18]*u[18] + d[23]*u[19]);
1441       uik[19]= -(d[4]*u[15] + d[9]*u[16] + d[14]*u[17] + d[19]*u[18] + d[24]*u[19]);
1442 
1443       uik[20]= -(d[0]*u[20] + d[5]*u[21] + d[10]*u[22] + d[15]*u[23] + d[20]*u[24]);
1444       uik[21]= -(d[1]*u[20] + d[6]*u[21] + d[11]*u[22] + d[16]*u[23] + d[21]*u[24]);
1445       uik[22]= -(d[2]*u[20] + d[7]*u[21] + d[12]*u[22] + d[17]*u[23] + d[22]*u[24]);
1446       uik[23]= -(d[3]*u[20] + d[8]*u[21] + d[13]*u[22] + d[18]*u[23] + d[23]*u[24]);
1447       uik[24]= -(d[4]*u[20] + d[9]*u[21] + d[14]*u[22] + d[19]*u[23] + d[24]*u[24]);
1448 
1449 
1450       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
1451       dk[0] +=  uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3] + uik[4]*u[4];
1452       dk[1] +=  uik[5]*u[0] + uik[6]*u[1] + uik[7]*u[2] + uik[8]*u[3] + uik[9]*u[4];
1453       dk[2] += uik[10]*u[0]+ uik[11]*u[1]+ uik[12]*u[2]+ uik[13]*u[3]+ uik[14]*u[4];
1454       dk[3] += uik[15]*u[0]+ uik[16]*u[1]+ uik[17]*u[2]+ uik[18]*u[3]+ uik[19]*u[4];
1455       dk[4] += uik[20]*u[0]+ uik[21]*u[1]+ uik[22]*u[2]+ uik[23]*u[3]+ uik[24]*u[4];
1456 
1457       dk[5] +=  uik[0]*u[5] + uik[1]*u[6] + uik[2]*u[7] + uik[3]*u[8] + uik[4]*u[9];
1458       dk[6] +=  uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7] + uik[8]*u[8] + uik[9]*u[9];
1459       dk[7] += uik[10]*u[5]+ uik[11]*u[6]+ uik[12]*u[7]+ uik[13]*u[8]+ uik[14]*u[9];
1460       dk[8] += uik[15]*u[5]+ uik[16]*u[6]+ uik[17]*u[7]+ uik[18]*u[8]+ uik[19]*u[9];
1461       dk[9] += uik[20]*u[5]+ uik[21]*u[6]+ uik[22]*u[7]+ uik[23]*u[8]+ uik[24]*u[9];
1462 
1463       dk[10] +=  uik[0]*u[10] + uik[1]*u[11] + uik[2]*u[12] + uik[3]*u[13] + uik[4]*u[14];
1464       dk[11] +=  uik[5]*u[10] + uik[6]*u[11] + uik[7]*u[12] + uik[8]*u[13] + uik[9]*u[14];
1465       dk[12] += uik[10]*u[10]+ uik[11]*u[11]+ uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14];
1466       dk[13] += uik[15]*u[10]+ uik[16]*u[11]+ uik[17]*u[12]+ uik[18]*u[13]+ uik[19]*u[14];
1467       dk[14] += uik[20]*u[10]+ uik[21]*u[11]+ uik[22]*u[12]+ uik[23]*u[13]+ uik[24]*u[14];
1468 
1469       dk[15] +=  uik[0]*u[15] + uik[1]*u[16] + uik[2]*u[17] + uik[3]*u[18] + uik[4]*u[19];
1470       dk[16] +=  uik[5]*u[15] + uik[6]*u[16] + uik[7]*u[17] + uik[8]*u[18] + uik[9]*u[19];
1471       dk[17] += uik[10]*u[15]+ uik[11]*u[16]+ uik[12]*u[17]+ uik[13]*u[18]+ uik[14]*u[19];
1472       dk[18] += uik[15]*u[15]+ uik[16]*u[16]+ uik[17]*u[17]+ uik[18]*u[18]+ uik[19]*u[19];
1473       dk[19] += uik[20]*u[15]+ uik[21]*u[16]+ uik[22]*u[17]+ uik[23]*u[18]+ uik[24]*u[19];
1474 
1475       dk[20] +=  uik[0]*u[20] + uik[1]*u[21] + uik[2]*u[22] + uik[3]*u[23] + uik[4]*u[24];
1476       dk[21] +=  uik[5]*u[20] + uik[6]*u[21] + uik[7]*u[22] + uik[8]*u[23] + uik[9]*u[24];
1477       dk[22] += uik[10]*u[20]+ uik[11]*u[21]+ uik[12]*u[22]+ uik[13]*u[23]+ uik[14]*u[24];
1478       dk[23] += uik[15]*u[20]+ uik[16]*u[21]+ uik[17]*u[22]+ uik[18]*u[23]+ uik[19]*u[24];
1479       dk[24] += uik[20]*u[20]+ uik[21]*u[21]+ uik[22]*u[22]+ uik[23]*u[23]+ uik[24]*u[24];
1480 
1481       /* update -U(i,k) */
1482       ierr = PetscMemcpy(ba+ili*25,uik,25*sizeof(MatScalar));CHKERRQ(ierr);
1483 
1484       /* add multiple of row i to k-th row ... */
1485       jmin = ili + 1; jmax = bi[i+1];
1486       if (jmin < jmax){
1487         for (j=jmin; j<jmax; j++) {
1488           /* rtmp += -U(i,k)^T * U_bar(i,j) */
1489           rtmp_ptr = rtmp + bj[j]*25;
1490           u = ba + j*25;
1491           rtmp_ptr[0] +=  uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3] + uik[4]*u[4];
1492           rtmp_ptr[1] +=  uik[5]*u[0] + uik[6]*u[1] + uik[7]*u[2] + uik[8]*u[3] + uik[9]*u[4];
1493           rtmp_ptr[2] += uik[10]*u[0]+ uik[11]*u[1]+ uik[12]*u[2]+ uik[13]*u[3]+ uik[14]*u[4];
1494           rtmp_ptr[3] += uik[15]*u[0]+ uik[16]*u[1]+ uik[17]*u[2]+ uik[18]*u[3]+ uik[19]*u[4];
1495           rtmp_ptr[4] += uik[20]*u[0]+ uik[21]*u[1]+ uik[22]*u[2]+ uik[23]*u[3]+ uik[24]*u[4];
1496 
1497           rtmp_ptr[5] +=  uik[0]*u[5] + uik[1]*u[6] + uik[2]*u[7] + uik[3]*u[8] + uik[4]*u[9];
1498           rtmp_ptr[6] +=  uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7] + uik[8]*u[8] + uik[9]*u[9];
1499           rtmp_ptr[7] += uik[10]*u[5]+ uik[11]*u[6]+ uik[12]*u[7]+ uik[13]*u[8]+ uik[14]*u[9];
1500           rtmp_ptr[8] += uik[15]*u[5]+ uik[16]*u[6]+ uik[17]*u[7]+ uik[18]*u[8]+ uik[19]*u[9];
1501           rtmp_ptr[9] += uik[20]*u[5]+ uik[21]*u[6]+ uik[22]*u[7]+ uik[23]*u[8]+ uik[24]*u[9];
1502 
1503           rtmp_ptr[10] +=  uik[0]*u[10] + uik[1]*u[11] + uik[2]*u[12] + uik[3]*u[13] + uik[4]*u[14];
1504           rtmp_ptr[11] +=  uik[5]*u[10] + uik[6]*u[11] + uik[7]*u[12] + uik[8]*u[13] + uik[9]*u[14];
1505           rtmp_ptr[12] += uik[10]*u[10]+ uik[11]*u[11]+ uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14];
1506           rtmp_ptr[13] += uik[15]*u[10]+ uik[16]*u[11]+ uik[17]*u[12]+ uik[18]*u[13]+ uik[19]*u[14];
1507           rtmp_ptr[14] += uik[20]*u[10]+ uik[21]*u[11]+ uik[22]*u[12]+ uik[23]*u[13]+ uik[24]*u[14];
1508 
1509           rtmp_ptr[15] +=  uik[0]*u[15] + uik[1]*u[16] + uik[2]*u[17] + uik[3]*u[18] + uik[4]*u[19];
1510           rtmp_ptr[16] +=  uik[5]*u[15] + uik[6]*u[16] + uik[7]*u[17] + uik[8]*u[18] + uik[9]*u[19];
1511           rtmp_ptr[17] += uik[10]*u[15]+ uik[11]*u[16]+ uik[12]*u[17]+ uik[13]*u[18]+ uik[14]*u[19];
1512           rtmp_ptr[18] += uik[15]*u[15]+ uik[16]*u[16]+ uik[17]*u[17]+ uik[18]*u[18]+ uik[19]*u[19];
1513           rtmp_ptr[19] += uik[20]*u[15]+ uik[21]*u[16]+ uik[22]*u[17]+ uik[23]*u[18]+ uik[24]*u[19];
1514 
1515           rtmp_ptr[20] +=  uik[0]*u[20] + uik[1]*u[21] + uik[2]*u[22] + uik[3]*u[23] + uik[4]*u[24];
1516           rtmp_ptr[21] +=  uik[5]*u[20] + uik[6]*u[21] + uik[7]*u[22] + uik[8]*u[23] + uik[9]*u[24];
1517           rtmp_ptr[22] += uik[10]*u[20]+ uik[11]*u[21]+ uik[12]*u[22]+ uik[13]*u[23]+ uik[14]*u[24];
1518           rtmp_ptr[23] += uik[15]*u[20]+ uik[16]*u[21]+ uik[17]*u[22]+ uik[18]*u[23]+ uik[19]*u[24];
1519           rtmp_ptr[24] += uik[20]*u[20]+ uik[21]*u[21]+ uik[22]*u[22]+ uik[23]*u[23]+ uik[24]*u[24];
1520         }
1521 
1522         /* ... add i to row list for next nonzero entry */
1523         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
1524         j     = bj[jmin];
1525         jl[i] = jl[j]; jl[j] = i; /* update jl */
1526       }
1527       i = nexti;
1528     }
1529 
1530     /* save nonzero entries in k-th row of U ... */
1531 
1532     /* invert diagonal block */
1533     d = ba+k*25;
1534     ierr = PetscMemcpy(d,dk,25*sizeof(MatScalar));CHKERRQ(ierr);
1535     ierr = Kernel_A_gets_inverse_A_5(d);CHKERRQ(ierr);
1536 
1537     jmin = bi[k]; jmax = bi[k+1];
1538     if (jmin < jmax) {
1539       for (j=jmin; j<jmax; j++){
1540          vj = bj[j];           /* block col. index of U */
1541          u   = ba + j*25;
1542          rtmp_ptr = rtmp + vj*25;
1543          for (k1=0; k1<25; k1++){
1544            *u++        = *rtmp_ptr;
1545            *rtmp_ptr++ = 0.0;
1546          }
1547       }
1548 
1549       /* ... add k to row list for first nonzero entry in k-th row */
1550       il[k] = jmin;
1551       i     = bj[jmin];
1552       jl[k] = jl[i]; jl[i] = k;
1553     }
1554   }
1555 
1556   ierr = PetscFree(rtmp);CHKERRQ(ierr);
1557   ierr = PetscFree(il);CHKERRQ(ierr);
1558   ierr = PetscFree(jl);CHKERRQ(ierr);
1559   ierr = PetscFree(dk);CHKERRQ(ierr);
1560   ierr = PetscFree(uik);CHKERRQ(ierr);
1561   if (a->permute){
1562     ierr = PetscFree(aa);CHKERRQ(ierr);
1563   }
1564 
1565   ierr = ISRestoreIndices(perm,&perm_ptr);CHKERRQ(ierr);
1566   C->factor    = FACTOR_CHOLESKY;
1567   C->assembled = PETSC_TRUE;
1568   C->preallocated = PETSC_TRUE;
1569   PLogFlops(1.3333*125*b->mbs); /* from inverting diagonal blocks */
1570   PetscFunctionReturn(0);
1571 }
1572 
1573 /*
1574       Version for when blocks are 5 by 5 Using natural ordering
1575 */
1576 #undef __FUNC__
1577 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_5_NaturalOrdering"
1578 int MatCholeskyFactorNumeric_SeqSBAIJ_5_NaturalOrdering(Mat A,Mat *B)
1579 {
1580   Mat         C = *B;
1581   Mat_SeqBAIJ *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
1582   int         ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
1583   int         *ajtmpold,*ajtmp,nz,row;
1584   int         *diag_offset = b->diag,*ai=a->i,*aj=a->j,*pj;
1585   MatScalar   *pv,*v,*rtmp,*pc,*w,*x;
1586   MatScalar   x1,x2,x3,x4,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15;
1587   MatScalar   x16,x17,x18,x19,x20,x21,x22,x23,x24,x25;
1588   MatScalar   p1,p2,p3,p4,p5,p6,p7,p8,p9,p10,p11,p12,p13,p14,p15;
1589   MatScalar   p16,p17,p18,p19,p20,p21,p22,p23,p24,p25;
1590   MatScalar   m1,m2,m3,m4,m5,m6,m7,m8,m9,m10,m11,m12,m13,m14,m15;
1591   MatScalar   m16,m17,m18,m19,m20,m21,m22,m23,m24,m25;
1592   MatScalar   *ba = b->a,*aa = a->a;
1593 
1594   PetscFunctionBegin;
1595   rtmp  = (MatScalar*)PetscMalloc(25*(n+1)*sizeof(MatScalar));CHKPTRQ(rtmp);
1596   for (i=0; i<n; i++) {
1597     nz    = bi[i+1] - bi[i];
1598     ajtmp = bj + bi[i];
1599     for  (j=0; j<nz; j++) {
1600       x = rtmp+25*ajtmp[j];
1601       x[0]  = x[1]  = x[2]  = x[3]  = x[4]  = x[5]  = x[6] = x[7] = x[8] = x[9] = 0.0;
1602       x[10] = x[11] = x[12] = x[13] = x[14] = x[15] = 0.0;
1603       x[16] = x[17] = x[18] = x[19] = x[20] = x[21] = x[22] = x[23] = x[24] = 0.0;
1604     }
1605     /* load in initial (unfactored row) */
1606     nz       = ai[i+1] - ai[i];
1607     ajtmpold = aj + ai[i];
1608     v        = aa + 25*ai[i];
1609     for (j=0; j<nz; j++) {
1610       x    = rtmp+25*ajtmpold[j];
1611       x[0]  = v[0];  x[1]  = v[1];  x[2]  = v[2];  x[3]  = v[3];
1612       x[4]  = v[4];  x[5]  = v[5];  x[6]  = v[6];  x[7]  = v[7];  x[8]  = v[8];
1613       x[9]  = v[9];  x[10] = v[10]; x[11] = v[11]; x[12] = v[12]; x[13] = v[13];
1614       x[14] = v[14]; x[15] = v[15]; x[16] = v[16]; x[17] = v[17]; x[18] = v[18];
1615       x[19] = v[19]; x[20] = v[20]; x[21] = v[21]; x[22] = v[22]; x[23] = v[23];
1616       x[24] = v[24];
1617       v    += 25;
1618     }
1619     row = *ajtmp++;
1620     while (row < i) {
1621       pc  = rtmp + 25*row;
1622       p1  = pc[0];  p2  = pc[1];  p3  = pc[2];  p4  = pc[3];
1623       p5  = pc[4];  p6  = pc[5];  p7  = pc[6];  p8  = pc[7];  p9  = pc[8];
1624       p10 = pc[9];  p11 = pc[10]; p12 = pc[11]; p13 = pc[12]; p14 = pc[13];
1625       p15 = pc[14]; p16 = pc[15]; p17 = pc[16]; p18 = pc[17];
1626       p19 = pc[18]; p20 = pc[19]; p21 = pc[20]; p22 = pc[21]; p23 = pc[22];
1627       p24 = pc[23]; p25 = pc[24];
1628       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0 || p5 != 0.0 ||
1629           p6 != 0.0 || p7 != 0.0 || p8 != 0.0 || p9 != 0.0 || p10 != 0.0 ||
1630           p11 != 0.0 || p12 != 0.0 || p13 != 0.0 || p14 != 0.0 || p15 != 0.0
1631           || p16 != 0.0 || p17 != 0.0 || p18 != 0.0 || p19 != 0.0 || p20 != 0.0
1632           || p21 != 0.0 || p22 != 0.0 || p23 != 0.0 || p24 != 0.0 || p25 != 0.0) {
1633         pv = ba + 25*diag_offset[row];
1634         pj = bj + diag_offset[row] + 1;
1635         x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
1636         x5  = pv[4];  x6  = pv[5];  x7  = pv[6];  x8  = pv[7];  x9  = pv[8];
1637         x10 = pv[9];  x11 = pv[10]; x12 = pv[11]; x13 = pv[12]; x14 = pv[13];
1638         x15 = pv[14]; x16 = pv[15]; x17 = pv[16]; x18 = pv[17]; x19 = pv[18];
1639         x20 = pv[19]; x21 = pv[20]; x22 = pv[21]; x23 = pv[22]; x24 = pv[23];
1640         x25 = pv[24];
1641         pc[0] = m1 = p1*x1 + p6*x2  + p11*x3 + p16*x4 + p21*x5;
1642         pc[1] = m2 = p2*x1 + p7*x2  + p12*x3 + p17*x4 + p22*x5;
1643         pc[2] = m3 = p3*x1 + p8*x2  + p13*x3 + p18*x4 + p23*x5;
1644         pc[3] = m4 = p4*x1 + p9*x2  + p14*x3 + p19*x4 + p24*x5;
1645         pc[4] = m5 = p5*x1 + p10*x2 + p15*x3 + p20*x4 + p25*x5;
1646 
1647         pc[5]  = m6  = p1*x6 + p6*x7  + p11*x8 + p16*x9 + p21*x10;
1648         pc[6]  = m7  = p2*x6 + p7*x7  + p12*x8 + p17*x9 + p22*x10;
1649         pc[7]  = m8  = p3*x6 + p8*x7  + p13*x8 + p18*x9 + p23*x10;
1650         pc[8]  = m9  = p4*x6 + p9*x7  + p14*x8 + p19*x9 + p24*x10;
1651         pc[9]  = m10 = p5*x6 + p10*x7 + p15*x8 + p20*x9 + p25*x10;
1652 
1653         pc[10] = m11 = p1*x11 + p6*x12  + p11*x13 + p16*x14 + p21*x15;
1654         pc[11] = m12 = p2*x11 + p7*x12  + p12*x13 + p17*x14 + p22*x15;
1655         pc[12] = m13 = p3*x11 + p8*x12  + p13*x13 + p18*x14 + p23*x15;
1656         pc[13] = m14 = p4*x11 + p9*x12  + p14*x13 + p19*x14 + p24*x15;
1657         pc[14] = m15 = p5*x11 + p10*x12 + p15*x13 + p20*x14 + p25*x15;
1658 
1659         pc[15] = m16 = p1*x16 + p6*x17  + p11*x18 + p16*x19 + p21*x20;
1660         pc[16] = m17 = p2*x16 + p7*x17  + p12*x18 + p17*x19 + p22*x20;
1661         pc[17] = m18 = p3*x16 + p8*x17  + p13*x18 + p18*x19 + p23*x20;
1662         pc[18] = m19 = p4*x16 + p9*x17  + p14*x18 + p19*x19 + p24*x20;
1663         pc[19] = m20 = p5*x16 + p10*x17 + p15*x18 + p20*x19 + p25*x20;
1664 
1665         pc[20] = m21 = p1*x21 + p6*x22  + p11*x23 + p16*x24 + p21*x25;
1666         pc[21] = m22 = p2*x21 + p7*x22  + p12*x23 + p17*x24 + p22*x25;
1667         pc[22] = m23 = p3*x21 + p8*x22  + p13*x23 + p18*x24 + p23*x25;
1668         pc[23] = m24 = p4*x21 + p9*x22  + p14*x23 + p19*x24 + p24*x25;
1669         pc[24] = m25 = p5*x21 + p10*x22 + p15*x23 + p20*x24 + p25*x25;
1670 
1671         nz = bi[row+1] - diag_offset[row] - 1;
1672         pv += 25;
1673         for (j=0; j<nz; j++) {
1674           x1   = pv[0];  x2  = pv[1];   x3 = pv[2];  x4  = pv[3];
1675           x5   = pv[4];  x6  = pv[5];   x7 = pv[6];  x8  = pv[7]; x9 = pv[8];
1676           x10  = pv[9];  x11 = pv[10]; x12 = pv[11]; x13 = pv[12];
1677           x14  = pv[13]; x15 = pv[14]; x16 = pv[15]; x17 = pv[16]; x18 = pv[17];
1678           x19 = pv[18];  x20 = pv[19]; x21 = pv[20]; x22 = pv[21]; x23 = pv[22];
1679           x24 = pv[23];  x25 = pv[24];
1680           x    = rtmp + 25*pj[j];
1681           x[0] -= m1*x1 + m6*x2   + m11*x3  + m16*x4 + m21*x5;
1682           x[1] -= m2*x1 + m7*x2   + m12*x3  + m17*x4 + m22*x5;
1683           x[2] -= m3*x1 + m8*x2   + m13*x3  + m18*x4 + m23*x5;
1684           x[3] -= m4*x1 + m9*x2   + m14*x3  + m19*x4 + m24*x5;
1685           x[4] -= m5*x1 + m10*x2  + m15*x3  + m20*x4 + m25*x5;
1686 
1687           x[5] -= m1*x6 + m6*x7   + m11*x8  + m16*x9 + m21*x10;
1688           x[6] -= m2*x6 + m7*x7   + m12*x8  + m17*x9 + m22*x10;
1689           x[7] -= m3*x6 + m8*x7   + m13*x8  + m18*x9 + m23*x10;
1690           x[8] -= m4*x6 + m9*x7   + m14*x8  + m19*x9 + m24*x10;
1691           x[9] -= m5*x6 + m10*x7  + m15*x8  + m20*x9 + m25*x10;
1692 
1693           x[10] -= m1*x11 + m6*x12  + m11*x13 + m16*x14 + m21*x15;
1694           x[11] -= m2*x11 + m7*x12  + m12*x13 + m17*x14 + m22*x15;
1695           x[12] -= m3*x11 + m8*x12  + m13*x13 + m18*x14 + m23*x15;
1696           x[13] -= m4*x11 + m9*x12  + m14*x13 + m19*x14 + m24*x15;
1697           x[14] -= m5*x11 + m10*x12 + m15*x13 + m20*x14 + m25*x15;
1698 
1699           x[15] -= m1*x16 + m6*x17  + m11*x18 + m16*x19 + m21*x20;
1700           x[16] -= m2*x16 + m7*x17  + m12*x18 + m17*x19 + m22*x20;
1701           x[17] -= m3*x16 + m8*x17  + m13*x18 + m18*x19 + m23*x20;
1702           x[18] -= m4*x16 + m9*x17  + m14*x18 + m19*x19 + m24*x20;
1703           x[19] -= m5*x16 + m10*x17 + m15*x18 + m20*x19 + m25*x20;
1704 
1705           x[20] -= m1*x21 + m6*x22  + m11*x23 + m16*x24 + m21*x25;
1706           x[21] -= m2*x21 + m7*x22  + m12*x23 + m17*x24 + m22*x25;
1707           x[22] -= m3*x21 + m8*x22  + m13*x23 + m18*x24 + m23*x25;
1708           x[23] -= m4*x21 + m9*x22  + m14*x23 + m19*x24 + m24*x25;
1709           x[24] -= m5*x21 + m10*x22 + m15*x23 + m20*x24 + m25*x25;
1710           pv   += 25;
1711         }
1712         PLogFlops(250*nz+225);
1713       }
1714       row = *ajtmp++;
1715     }
1716     /* finished row so stick it into b->a */
1717     pv = ba + 25*bi[i];
1718     pj = bj + bi[i];
1719     nz = bi[i+1] - bi[i];
1720     for (j=0; j<nz; j++) {
1721       x      = rtmp+25*pj[j];
1722       pv[0]  = x[0];  pv[1]  = x[1];  pv[2]  = x[2];  pv[3]  = x[3];
1723       pv[4]  = x[4];  pv[5]  = x[5];  pv[6]  = x[6];  pv[7]  = x[7]; pv[8] = x[8];
1724       pv[9]  = x[9];  pv[10] = x[10]; pv[11] = x[11]; pv[12] = x[12];
1725       pv[13] = x[13]; pv[14] = x[14]; pv[15] = x[15]; pv[16] = x[16]; pv[17] = x[17];
1726       pv[18] = x[18]; pv[19] = x[19]; pv[20] = x[20]; pv[21] = x[21]; pv[22] = x[22];
1727       pv[23] = x[23]; pv[24] = x[24];
1728       pv   += 25;
1729     }
1730     /* invert diagonal block */
1731     w = ba + 25*diag_offset[i];
1732     ierr = Kernel_A_gets_inverse_A_5(w);CHKERRQ(ierr);
1733   }
1734 
1735   ierr = PetscFree(rtmp);CHKERRQ(ierr);
1736   C->factor    = FACTOR_LU;
1737   C->assembled = PETSC_TRUE;
1738   PLogFlops(1.3333*125*b->mbs); /* from inverting diagonal blocks */
1739   PetscFunctionReturn(0);
1740 }
1741 
1742 /*
1743       Version for when blocks are 4 by 4 Using natural ordering
1744 */
1745 #undef __FUNC__
1746 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_4_NaturalOrdering"
1747 int MatCholeskyFactorNumeric_SeqSBAIJ_4_NaturalOrdering(Mat A,Mat *B)
1748 {
1749   Mat         C = *B;
1750   Mat_SeqBAIJ *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
1751   int         ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
1752   int         *ajtmpold,*ajtmp,nz,row;
1753   int         *diag_offset = b->diag,*ai=a->i,*aj=a->j,*pj;
1754   MatScalar   *pv,*v,*rtmp,*pc,*w,*x;
1755   MatScalar   p1,p2,p3,p4,m1,m2,m3,m4,m5,m6,m7,m8,m9,x1,x2,x3,x4;
1756   MatScalar   p5,p6,p7,p8,p9,x5,x6,x7,x8,x9,x10,x11,x12,x13,x14,x15,x16;
1757   MatScalar   p10,p11,p12,p13,p14,p15,p16,m10,m11,m12;
1758   MatScalar   m13,m14,m15,m16;
1759   MatScalar   *ba = b->a,*aa = a->a;
1760 
1761   PetscFunctionBegin;
1762   rtmp  = (MatScalar*)PetscMalloc(16*(n+1)*sizeof(MatScalar));CHKPTRQ(rtmp);
1763 
1764   for (i=0; i<n; i++) {
1765     nz    = bi[i+1] - bi[i];
1766     ajtmp = bj + bi[i];
1767     for  (j=0; j<nz; j++) {
1768       x = rtmp+16*ajtmp[j];
1769       x[0]  = x[1]  = x[2]  = x[3]  = x[4]  = x[5]  = x[6] = x[7] = x[8] = x[9] = 0.0;
1770       x[10] = x[11] = x[12] = x[13] = x[14] = x[15] = 0.0;
1771     }
1772     /* load in initial (unfactored row) */
1773     nz       = ai[i+1] - ai[i];
1774     ajtmpold = aj + ai[i];
1775     v        = aa + 16*ai[i];
1776     for (j=0; j<nz; j++) {
1777       x    = rtmp+16*ajtmpold[j];
1778       x[0]  = v[0];  x[1]  = v[1];  x[2]  = v[2];  x[3]  = v[3];
1779       x[4]  = v[4];  x[5]  = v[5];  x[6]  = v[6];  x[7]  = v[7];  x[8]  = v[8];
1780       x[9]  = v[9];  x[10] = v[10]; x[11] = v[11]; x[12] = v[12]; x[13] = v[13];
1781       x[14] = v[14]; x[15] = v[15];
1782       v    += 16;
1783     }
1784     row = *ajtmp++;
1785     while (row < i) {
1786       pc  = rtmp + 16*row;
1787       p1  = pc[0];  p2  = pc[1];  p3  = pc[2];  p4  = pc[3];
1788       p5  = pc[4];  p6  = pc[5];  p7  = pc[6];  p8  = pc[7];  p9  = pc[8];
1789       p10 = pc[9];  p11 = pc[10]; p12 = pc[11]; p13 = pc[12]; p14 = pc[13];
1790       p15 = pc[14]; p16 = pc[15];
1791       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0 || p5 != 0.0 ||
1792           p6 != 0.0 || p7 != 0.0 || p8 != 0.0 || p9 != 0.0 || p10 != 0.0 ||
1793           p11 != 0.0 || p12 != 0.0 || p13 != 0.0 || p14 != 0.0 || p15 != 0.0
1794           || p16 != 0.0) {
1795         pv = ba + 16*diag_offset[row];
1796         pj = bj + diag_offset[row] + 1;
1797         x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
1798         x5  = pv[4];  x6  = pv[5];  x7  = pv[6];  x8  = pv[7];  x9  = pv[8];
1799         x10 = pv[9];  x11 = pv[10]; x12 = pv[11]; x13 = pv[12]; x14 = pv[13];
1800         x15 = pv[14]; x16 = pv[15];
1801         pc[0] = m1 = p1*x1 + p5*x2  + p9*x3  + p13*x4;
1802         pc[1] = m2 = p2*x1 + p6*x2  + p10*x3 + p14*x4;
1803         pc[2] = m3 = p3*x1 + p7*x2  + p11*x3 + p15*x4;
1804         pc[3] = m4 = p4*x1 + p8*x2  + p12*x3 + p16*x4;
1805 
1806         pc[4] = m5 = p1*x5 + p5*x6  + p9*x7  + p13*x8;
1807         pc[5] = m6 = p2*x5 + p6*x6  + p10*x7 + p14*x8;
1808         pc[6] = m7 = p3*x5 + p7*x6  + p11*x7 + p15*x8;
1809         pc[7] = m8 = p4*x5 + p8*x6  + p12*x7 + p16*x8;
1810 
1811         pc[8]  = m9  = p1*x9 + p5*x10  + p9*x11  + p13*x12;
1812         pc[9]  = m10 = p2*x9 + p6*x10  + p10*x11 + p14*x12;
1813         pc[10] = m11 = p3*x9 + p7*x10  + p11*x11 + p15*x12;
1814         pc[11] = m12 = p4*x9 + p8*x10  + p12*x11 + p16*x12;
1815 
1816         pc[12] = m13 = p1*x13 + p5*x14  + p9*x15  + p13*x16;
1817         pc[13] = m14 = p2*x13 + p6*x14  + p10*x15 + p14*x16;
1818         pc[14] = m15 = p3*x13 + p7*x14  + p11*x15 + p15*x16;
1819         pc[15] = m16 = p4*x13 + p8*x14  + p12*x15 + p16*x16;
1820 
1821         nz = bi[row+1] - diag_offset[row] - 1;
1822         pv += 16;
1823         for (j=0; j<nz; j++) {
1824           x1   = pv[0];  x2  = pv[1];   x3 = pv[2];  x4  = pv[3];
1825           x5   = pv[4];  x6  = pv[5];   x7 = pv[6];  x8  = pv[7]; x9 = pv[8];
1826           x10  = pv[9];  x11 = pv[10]; x12 = pv[11]; x13 = pv[12];
1827           x14  = pv[13]; x15 = pv[14]; x16 = pv[15];
1828           x    = rtmp + 16*pj[j];
1829           x[0] -= m1*x1 + m5*x2  + m9*x3  + m13*x4;
1830           x[1] -= m2*x1 + m6*x2  + m10*x3 + m14*x4;
1831           x[2] -= m3*x1 + m7*x2  + m11*x3 + m15*x4;
1832           x[3] -= m4*x1 + m8*x2  + m12*x3 + m16*x4;
1833 
1834           x[4] -= m1*x5 + m5*x6  + m9*x7  + m13*x8;
1835           x[5] -= m2*x5 + m6*x6  + m10*x7 + m14*x8;
1836           x[6] -= m3*x5 + m7*x6  + m11*x7 + m15*x8;
1837           x[7] -= m4*x5 + m8*x6  + m12*x7 + m16*x8;
1838 
1839           x[8]  -= m1*x9 + m5*x10 + m9*x11  + m13*x12;
1840           x[9]  -= m2*x9 + m6*x10 + m10*x11 + m14*x12;
1841           x[10] -= m3*x9 + m7*x10 + m11*x11 + m15*x12;
1842           x[11] -= m4*x9 + m8*x10 + m12*x11 + m16*x12;
1843 
1844           x[12] -= m1*x13 + m5*x14  + m9*x15  + m13*x16;
1845           x[13] -= m2*x13 + m6*x14  + m10*x15 + m14*x16;
1846           x[14] -= m3*x13 + m7*x14  + m11*x15 + m15*x16;
1847           x[15] -= m4*x13 + m8*x14  + m12*x15 + m16*x16;
1848 
1849           pv   += 16;
1850         }
1851         PLogFlops(128*nz+112);
1852       }
1853       row = *ajtmp++;
1854     }
1855     /* finished row so stick it into b->a */
1856     pv = ba + 16*bi[i];
1857     pj = bj + bi[i];
1858     nz = bi[i+1] - bi[i];
1859     for (j=0; j<nz; j++) {
1860       x      = rtmp+16*pj[j];
1861       pv[0]  = x[0];  pv[1]  = x[1];  pv[2]  = x[2];  pv[3]  = x[3];
1862       pv[4]  = x[4];  pv[5]  = x[5];  pv[6]  = x[6];  pv[7]  = x[7]; pv[8] = x[8];
1863       pv[9]  = x[9];  pv[10] = x[10]; pv[11] = x[11]; pv[12] = x[12];
1864       pv[13] = x[13]; pv[14] = x[14]; pv[15] = x[15];
1865       pv   += 16;
1866     }
1867     /* invert diagonal block */
1868     w = ba + 16*diag_offset[i];
1869     ierr = Kernel_A_gets_inverse_A_4(w);CHKERRQ(ierr);
1870   }
1871 
1872   ierr = PetscFree(rtmp);CHKERRQ(ierr);
1873   C->factor    = FACTOR_LU;
1874   C->assembled = PETSC_TRUE;
1875   C->preallocated = PETSC_TRUE;
1876   PLogFlops(1.3333*64*b->mbs); /* from inverting diagonal blocks */
1877   PetscFunctionReturn(0);
1878 }
1879 
1880 /* Version for when blocks are 4 by 4  */
1881 #undef __FUNC__
1882 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_4"
1883 int MatCholeskyFactorNumeric_SeqSBAIJ_4(Mat A,Mat *B)
1884 {
1885   Mat                C = *B;
1886   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
1887   IS                 perm = b->row;
1888   int                *perm_ptr,ierr,i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
1889   int                *ai,*aj,*a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
1890   MatScalar          *ba = b->a,*aa,*ap,*dk,*uik;
1891   MatScalar          *u,*diag,*rtmp,*rtmp_ptr;
1892 
1893   PetscFunctionBegin;
1894   /* initialization */
1895   rtmp  = (MatScalar*)PetscMalloc(16*mbs*sizeof(MatScalar));CHKPTRQ(rtmp);
1896   ierr = PetscMemzero(rtmp,16*mbs*sizeof(MatScalar));CHKERRQ(ierr);
1897   il = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(il);
1898   jl = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(jl);
1899   for (i=0; i<mbs; i++) {
1900     jl[i] = mbs; il[0] = 0;
1901   }
1902   dk    = (MatScalar*)PetscMalloc(16*sizeof(MatScalar));CHKPTRQ(dk);
1903   uik   = (MatScalar*)PetscMalloc(16*sizeof(MatScalar));CHKPTRQ(uik);
1904   ierr  = ISGetIndices(perm,&perm_ptr);CHKERRQ(ierr);
1905 
1906   /* check permutation */
1907   if (!a->permute){
1908     ai = a->i; aj = a->j; aa = a->a;
1909   } else {
1910     ai = a->inew; aj = a->jnew;
1911     aa = (MatScalar*)PetscMalloc(16*ai[mbs]*sizeof(MatScalar));CHKPTRQ(aa);
1912     ierr = PetscMemcpy(aa,a->a,16*ai[mbs]*sizeof(MatScalar));CHKERRQ(ierr);
1913     a2anew  = (int*)PetscMalloc(ai[mbs]*sizeof(int));CHKPTRQ(a2anew);
1914     ierr= PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(int));CHKERRQ(ierr);
1915 
1916     for (i=0; i<mbs; i++){
1917       jmin = ai[i]; jmax = ai[i+1];
1918       for (j=jmin; j<jmax; j++){
1919         while (a2anew[j] != j){
1920           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
1921           for (k1=0; k1<16; k1++){
1922             dk[k1]       = aa[k*16+k1];
1923             aa[k*16+k1] = aa[j*16+k1];
1924             aa[j*16+k1] = dk[k1];
1925           }
1926         }
1927         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
1928         if (i > aj[j]){
1929           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
1930           ap = aa + j*16;                     /* ptr to the beginning of j-th block of aa */
1931           for (k=0; k<16; k++) dk[k] = ap[k]; /* dk <- j-th block of aa */
1932           for (k=0; k<4; k++){               /* j-th block of aa <- dk^T */
1933             for (k1=0; k1<4; k1++) *ap++ = dk[k + 4*k1];
1934           }
1935         }
1936       }
1937     }
1938     ierr = PetscFree(a2anew);CHKERRA(ierr);
1939   }
1940 
1941   /* for each row k */
1942   for (k = 0; k<mbs; k++){
1943 
1944     /*initialize k-th row with elements nonzero in row perm(k) of A */
1945     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];
1946     if (jmin < jmax) {
1947       ap = aa + jmin*16;
1948       for (j = jmin; j < jmax; j++){
1949         vj = perm_ptr[aj[j]];         /* block col. index */
1950         rtmp_ptr = rtmp + vj*16;
1951         for (i=0; i<16; i++) *rtmp_ptr++ = *ap++;
1952       }
1953     }
1954 
1955     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
1956     ierr = PetscMemcpy(dk,rtmp+k*16,16*sizeof(MatScalar));CHKERRQ(ierr);
1957     i = jl[k]; /* first row to be added to k_th row  */
1958 
1959     while (i < mbs){
1960       nexti = jl[i]; /* next row to be added to k_th row */
1961 
1962       /* compute multiplier */
1963       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
1964 
1965       /* uik = -inv(Di)*U_bar(i,k) */
1966       diag = ba + i*16;
1967       u    = ba + ili*16;
1968 
1969       uik[0] = -(diag[0]*u[0] + diag[4]*u[1] + diag[8]*u[2] + diag[12]*u[3]);
1970       uik[1] = -(diag[1]*u[0] + diag[5]*u[1] + diag[9]*u[2] + diag[13]*u[3]);
1971       uik[2] = -(diag[2]*u[0] + diag[6]*u[1] + diag[10]*u[2]+ diag[14]*u[3]);
1972       uik[3] = -(diag[3]*u[0] + diag[7]*u[1] + diag[11]*u[2]+ diag[15]*u[3]);
1973 
1974       uik[4] = -(diag[0]*u[4] + diag[4]*u[5] + diag[8]*u[6] + diag[12]*u[7]);
1975       uik[5] = -(diag[1]*u[4] + diag[5]*u[5] + diag[9]*u[6] + diag[13]*u[7]);
1976       uik[6] = -(diag[2]*u[4] + diag[6]*u[5] + diag[10]*u[6]+ diag[14]*u[7]);
1977       uik[7] = -(diag[3]*u[4] + diag[7]*u[5] + diag[11]*u[6]+ diag[15]*u[7]);
1978 
1979       uik[8] = -(diag[0]*u[8] + diag[4]*u[9] + diag[8]*u[10] + diag[12]*u[11]);
1980       uik[9] = -(diag[1]*u[8] + diag[5]*u[9] + diag[9]*u[10] + diag[13]*u[11]);
1981       uik[10]= -(diag[2]*u[8] + diag[6]*u[9] + diag[10]*u[10]+ diag[14]*u[11]);
1982       uik[11]= -(diag[3]*u[8] + diag[7]*u[9] + diag[11]*u[10]+ diag[15]*u[11]);
1983 
1984       uik[12]= -(diag[0]*u[12] + diag[4]*u[13] + diag[8]*u[14] + diag[12]*u[15]);
1985       uik[13]= -(diag[1]*u[12] + diag[5]*u[13] + diag[9]*u[14] + diag[13]*u[15]);
1986       uik[14]= -(diag[2]*u[12] + diag[6]*u[13] + diag[10]*u[14]+ diag[14]*u[15]);
1987       uik[15]= -(diag[3]*u[12] + diag[7]*u[13] + diag[11]*u[14]+ diag[15]*u[15]);
1988 
1989       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
1990       dk[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
1991       dk[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
1992       dk[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
1993       dk[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
1994 
1995       dk[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
1996       dk[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
1997       dk[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
1998       dk[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
1999 
2000       dk[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
2001       dk[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
2002       dk[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
2003       dk[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
2004 
2005       dk[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
2006       dk[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
2007       dk[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
2008       dk[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
2009 
2010       /* update -U(i,k) */
2011       ierr = PetscMemcpy(ba+ili*16,uik,16*sizeof(MatScalar));CHKERRQ(ierr);
2012 
2013       /* add multiple of row i to k-th row ... */
2014       jmin = ili + 1; jmax = bi[i+1];
2015       if (jmin < jmax){
2016         for (j=jmin; j<jmax; j++) {
2017           /* rtmp += -U(i,k)^T * U_bar(i,j) */
2018           rtmp_ptr = rtmp + bj[j]*16;
2019           u = ba + j*16;
2020           rtmp_ptr[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
2021           rtmp_ptr[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
2022           rtmp_ptr[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
2023           rtmp_ptr[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
2024 
2025           rtmp_ptr[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
2026           rtmp_ptr[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
2027           rtmp_ptr[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
2028           rtmp_ptr[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
2029 
2030           rtmp_ptr[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
2031           rtmp_ptr[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
2032           rtmp_ptr[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
2033           rtmp_ptr[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
2034 
2035           rtmp_ptr[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
2036           rtmp_ptr[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
2037           rtmp_ptr[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
2038           rtmp_ptr[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
2039         }
2040 
2041         /* ... add i to row list for next nonzero entry */
2042         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
2043         j     = bj[jmin];
2044         jl[i] = jl[j]; jl[j] = i; /* update jl */
2045       }
2046       i = nexti;
2047     }
2048 
2049     /* save nonzero entries in k-th row of U ... */
2050 
2051     /* invert diagonal block */
2052     diag = ba+k*16;
2053     ierr = PetscMemcpy(diag,dk,16*sizeof(MatScalar));CHKERRQ(ierr);
2054     ierr = Kernel_A_gets_inverse_A_4(diag);CHKERRQ(ierr);
2055 
2056     jmin = bi[k]; jmax = bi[k+1];
2057     if (jmin < jmax) {
2058       for (j=jmin; j<jmax; j++){
2059          vj = bj[j];           /* block col. index of U */
2060          u   = ba + j*16;
2061          rtmp_ptr = rtmp + vj*16;
2062          for (k1=0; k1<16; k1++){
2063            *u++        = *rtmp_ptr;
2064            *rtmp_ptr++ = 0.0;
2065          }
2066       }
2067 
2068       /* ... add k to row list for first nonzero entry in k-th row */
2069       il[k] = jmin;
2070       i     = bj[jmin];
2071       jl[k] = jl[i]; jl[i] = k;
2072     }
2073   }
2074 
2075   ierr = PetscFree(rtmp);CHKERRQ(ierr);
2076   ierr = PetscFree(il);CHKERRQ(ierr);
2077   ierr = PetscFree(jl);CHKERRQ(ierr);
2078   ierr = PetscFree(dk);CHKERRQ(ierr);
2079   ierr = PetscFree(uik);CHKERRQ(ierr);
2080   if (a->permute){
2081     ierr = PetscFree(aa);CHKERRQ(ierr);
2082   }
2083 
2084   ierr = ISRestoreIndices(perm,&perm_ptr);CHKERRQ(ierr);
2085   C->factor    = FACTOR_CHOLESKY;
2086   C->assembled = PETSC_TRUE;
2087   C->preallocated = PETSC_TRUE;
2088   PLogFlops(1.3333*64*b->mbs); /* from inverting diagonal blocks */
2089   PetscFunctionReturn(0);
2090 }
2091 
2092 /* Version for when blocks are 3 by 3  */
2093 #undef __FUNC__
2094 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_3"
2095 int MatCholeskyFactorNumeric_SeqSBAIJ_3(Mat A,Mat *B)
2096 {
2097   Mat                C = *B;
2098   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
2099   IS                 perm = b->row;
2100   int                *perm_ptr,ierr,i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
2101   int                *ai,*aj,*a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
2102   MatScalar          *ba = b->a,*aa,*ap,*dk,*uik;
2103   MatScalar          *u,*diag,*rtmp,*rtmp_ptr;
2104 
2105   PetscFunctionBegin;
2106   /* initialization */
2107   rtmp  = (MatScalar*)PetscMalloc(9*mbs*sizeof(MatScalar));CHKPTRQ(rtmp);
2108   ierr = PetscMemzero(rtmp,9*mbs*sizeof(MatScalar));CHKERRQ(ierr);
2109   il = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(il);
2110   jl = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(jl);
2111   for (i=0; i<mbs; i++) {
2112     jl[i] = mbs; il[0] = 0;
2113   }
2114   dk  = (MatScalar*)PetscMalloc(9*sizeof(MatScalar));CHKPTRQ(dk);
2115   uik = (MatScalar*)PetscMalloc(9*sizeof(MatScalar));CHKPTRQ(uik);
2116   ierr  = ISGetIndices(perm,&perm_ptr);CHKERRQ(ierr);
2117 
2118   /* check permutation */
2119   if (!a->permute){
2120     ai = a->i; aj = a->j; aa = a->a;
2121   } else {
2122     ai = a->inew; aj = a->jnew;
2123     aa = (MatScalar*)PetscMalloc(9*ai[mbs]*sizeof(MatScalar));CHKPTRQ(aa);
2124     ierr = PetscMemcpy(aa,a->a,9*ai[mbs]*sizeof(MatScalar));CHKERRQ(ierr);
2125     a2anew  = (int*)PetscMalloc(ai[mbs]*sizeof(int));CHKPTRQ(a2anew);
2126     ierr= PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(int));CHKERRQ(ierr);
2127 
2128     for (i=0; i<mbs; i++){
2129       jmin = ai[i]; jmax = ai[i+1];
2130       for (j=jmin; j<jmax; j++){
2131         while (a2anew[j] != j){
2132           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
2133           for (k1=0; k1<9; k1++){
2134             dk[k1]       = aa[k*9+k1];
2135             aa[k*9+k1] = aa[j*9+k1];
2136             aa[j*9+k1] = dk[k1];
2137           }
2138         }
2139         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
2140         if (i > aj[j]){
2141           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
2142           ap = aa + j*9;                     /* ptr to the beginning of j-th block of aa */
2143           for (k=0; k<9; k++) dk[k] = ap[k]; /* dk <- j-th block of aa */
2144           for (k=0; k<3; k++){               /* j-th block of aa <- dk^T */
2145             for (k1=0; k1<3; k1++) *ap++ = dk[k + 3*k1];
2146           }
2147         }
2148       }
2149     }
2150     ierr = PetscFree(a2anew);CHKERRA(ierr);
2151   }
2152 
2153   /* for each row k */
2154   for (k = 0; k<mbs; k++){
2155 
2156     /*initialize k-th row with elements nonzero in row perm(k) of A */
2157     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];
2158     if (jmin < jmax) {
2159       ap = aa + jmin*9;
2160       for (j = jmin; j < jmax; j++){
2161         vj = perm_ptr[aj[j]];         /* block col. index */
2162         rtmp_ptr = rtmp + vj*9;
2163         for (i=0; i<9; i++) *rtmp_ptr++ = *ap++;
2164       }
2165     }
2166 
2167     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
2168     ierr = PetscMemcpy(dk,rtmp+k*9,9*sizeof(MatScalar));CHKERRQ(ierr);
2169     i = jl[k]; /* first row to be added to k_th row  */
2170 
2171     while (i < mbs){
2172       nexti = jl[i]; /* next row to be added to k_th row */
2173 
2174       /* compute multiplier */
2175       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
2176 
2177       /* uik = -inv(Di)*U_bar(i,k) */
2178       diag = ba + i*9;
2179       u    = ba + ili*9;
2180 
2181       uik[0] = -(diag[0]*u[0] + diag[3]*u[1] + diag[6]*u[2]);
2182       uik[1] = -(diag[1]*u[0] + diag[4]*u[1] + diag[7]*u[2]);
2183       uik[2] = -(diag[2]*u[0] + diag[5]*u[1] + diag[8]*u[2]);
2184 
2185       uik[3] = -(diag[0]*u[3] + diag[3]*u[4] + diag[6]*u[5]);
2186       uik[4] = -(diag[1]*u[3] + diag[4]*u[4] + diag[7]*u[5]);
2187       uik[5] = -(diag[2]*u[3] + diag[5]*u[4] + diag[8]*u[5]);
2188 
2189       uik[6] = -(diag[0]*u[6] + diag[3]*u[7] + diag[6]*u[8]);
2190       uik[7] = -(diag[1]*u[6] + diag[4]*u[7] + diag[7]*u[8]);
2191       uik[8] = -(diag[2]*u[6] + diag[5]*u[7] + diag[8]*u[8]);
2192 
2193       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
2194       dk[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2];
2195       dk[1] += uik[3]*u[0] + uik[4]*u[1] + uik[5]*u[2];
2196       dk[2] += uik[6]*u[0] + uik[7]*u[1] + uik[8]*u[2];
2197 
2198       dk[3] += uik[0]*u[3] + uik[1]*u[4] + uik[2]*u[5];
2199       dk[4] += uik[3]*u[3] + uik[4]*u[4] + uik[5]*u[5];
2200       dk[5] += uik[6]*u[3] + uik[7]*u[4] + uik[8]*u[5];
2201 
2202       dk[6] += uik[0]*u[6] + uik[1]*u[7] + uik[2]*u[8];
2203       dk[7] += uik[3]*u[6] + uik[4]*u[7] + uik[5]*u[8];
2204       dk[8] += uik[6]*u[6] + uik[7]*u[7] + uik[8]*u[8];
2205 
2206       /* update -U(i,k) */
2207       ierr = PetscMemcpy(ba+ili*9,uik,9*sizeof(MatScalar));CHKERRQ(ierr);
2208 
2209       /* add multiple of row i to k-th row ... */
2210       jmin = ili + 1; jmax = bi[i+1];
2211       if (jmin < jmax){
2212         for (j=jmin; j<jmax; j++) {
2213           /* rtmp += -U(i,k)^T * U_bar(i,j) */
2214           rtmp_ptr = rtmp + bj[j]*9;
2215           u = ba + j*9;
2216           rtmp_ptr[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2];
2217           rtmp_ptr[1] += uik[3]*u[0] + uik[4]*u[1] + uik[5]*u[2];
2218           rtmp_ptr[2] += uik[6]*u[0] + uik[7]*u[1] + uik[8]*u[2];
2219 
2220           rtmp_ptr[3] += uik[0]*u[3] + uik[1]*u[4] + uik[2]*u[5];
2221           rtmp_ptr[4] += uik[3]*u[3] + uik[4]*u[4] + uik[5]*u[5];
2222           rtmp_ptr[5] += uik[6]*u[3] + uik[7]*u[4] + uik[8]*u[5];
2223 
2224           rtmp_ptr[6] += uik[0]*u[6] + uik[1]*u[7] + uik[2]*u[8];
2225           rtmp_ptr[7] += uik[3]*u[6] + uik[4]*u[7] + uik[5]*u[8];
2226           rtmp_ptr[8] += uik[6]*u[6] + uik[7]*u[7] + uik[8]*u[8];
2227         }
2228 
2229         /* ... add i to row list for next nonzero entry */
2230         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
2231         j     = bj[jmin];
2232         jl[i] = jl[j]; jl[j] = i; /* update jl */
2233       }
2234       i = nexti;
2235     }
2236 
2237     /* save nonzero entries in k-th row of U ... */
2238 
2239     /* invert diagonal block */
2240     diag = ba+k*9;
2241     ierr = PetscMemcpy(diag,dk,9*sizeof(MatScalar));CHKERRQ(ierr);
2242     ierr = Kernel_A_gets_inverse_A_3(diag);CHKERRQ(ierr);
2243 
2244     jmin = bi[k]; jmax = bi[k+1];
2245     if (jmin < jmax) {
2246       for (j=jmin; j<jmax; j++){
2247          vj = bj[j];           /* block col. index of U */
2248          u   = ba + j*9;
2249          rtmp_ptr = rtmp + vj*9;
2250          for (k1=0; k1<9; k1++){
2251            *u++        = *rtmp_ptr;
2252            *rtmp_ptr++ = 0.0;
2253          }
2254       }
2255 
2256       /* ... add k to row list for first nonzero entry in k-th row */
2257       il[k] = jmin;
2258       i     = bj[jmin];
2259       jl[k] = jl[i]; jl[i] = k;
2260     }
2261   }
2262 
2263   ierr = PetscFree(rtmp);CHKERRQ(ierr);
2264   ierr = PetscFree(il);CHKERRQ(ierr);
2265   ierr = PetscFree(jl);CHKERRQ(ierr);
2266   ierr = PetscFree(dk);CHKERRQ(ierr);
2267   ierr = PetscFree(uik);CHKERRQ(ierr);
2268   if (a->permute){
2269     ierr = PetscFree(aa);CHKERRQ(ierr);
2270   }
2271 
2272   ierr = ISRestoreIndices(perm,&perm_ptr);CHKERRQ(ierr);
2273   C->factor    = FACTOR_CHOLESKY;
2274   C->assembled = PETSC_TRUE;
2275   C->preallocated = PETSC_TRUE;
2276   PLogFlops(1.3333*27*b->mbs); /* from inverting diagonal blocks */
2277   PetscFunctionReturn(0);
2278 }
2279 
2280 /*
2281       Version for when blocks are 3 by 3 Using natural ordering
2282 */
2283 #undef __FUNC__
2284 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_3_NaturalOrdering"
2285 int MatCholeskyFactorNumeric_SeqSBAIJ_3_NaturalOrdering(Mat A,Mat *B)
2286 {
2287   Mat                C = *B;
2288   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
2289   int                ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
2290   int                *ajtmpold,*ajtmp,nz,row;
2291   int                *diag_offset = b->diag,*ai=a->i,*aj=a->j,*pj;
2292   MatScalar          *pv,*v,*rtmp,*pc,*w,*x;
2293   MatScalar          p1,p2,p3,p4,m1,m2,m3,m4,m5,m6,m7,m8,m9,x1,x2,x3,x4;
2294   MatScalar          p5,p6,p7,p8,p9,x5,x6,x7,x8,x9;
2295   MatScalar          *ba = b->a,*aa = a->a;
2296 
2297   PetscFunctionBegin;
2298   rtmp  = (MatScalar*)PetscMalloc(9*(n+1)*sizeof(MatScalar));CHKPTRQ(rtmp);
2299 
2300   for (i=0; i<n; i++) {
2301     nz    = bi[i+1] - bi[i];
2302     ajtmp = bj + bi[i];
2303     for  (j=0; j<nz; j++) {
2304       x = rtmp+9*ajtmp[j];
2305       x[0]  = x[1]  = x[2]  = x[3]  = x[4]  = x[5]  = x[6] = x[7] = x[8] = 0.0;
2306     }
2307     /* load in initial (unfactored row) */
2308     nz       = ai[i+1] - ai[i];
2309     ajtmpold = aj + ai[i];
2310     v        = aa + 9*ai[i];
2311     for (j=0; j<nz; j++) {
2312       x    = rtmp+9*ajtmpold[j];
2313       x[0]  = v[0];  x[1]  = v[1];  x[2]  = v[2];  x[3]  = v[3];
2314       x[4]  = v[4];  x[5]  = v[5];  x[6]  = v[6];  x[7]  = v[7];  x[8]  = v[8];
2315       v    += 9;
2316     }
2317     row = *ajtmp++;
2318     while (row < i) {
2319       pc  = rtmp + 9*row;
2320       p1  = pc[0];  p2  = pc[1];  p3  = pc[2];  p4  = pc[3];
2321       p5  = pc[4];  p6  = pc[5];  p7  = pc[6];  p8  = pc[7];  p9  = pc[8];
2322       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0 || p5 != 0.0 ||
2323           p6 != 0.0 || p7 != 0.0 || p8 != 0.0 || p9 != 0.0) {
2324         pv = ba + 9*diag_offset[row];
2325         pj = bj + diag_offset[row] + 1;
2326         x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
2327         x5  = pv[4];  x6  = pv[5];  x7  = pv[6];  x8  = pv[7];  x9  = pv[8];
2328         pc[0] = m1 = p1*x1 + p4*x2 + p7*x3;
2329         pc[1] = m2 = p2*x1 + p5*x2 + p8*x3;
2330         pc[2] = m3 = p3*x1 + p6*x2 + p9*x3;
2331 
2332         pc[3] = m4 = p1*x4 + p4*x5 + p7*x6;
2333         pc[4] = m5 = p2*x4 + p5*x5 + p8*x6;
2334         pc[5] = m6 = p3*x4 + p6*x5 + p9*x6;
2335 
2336         pc[6] = m7 = p1*x7 + p4*x8 + p7*x9;
2337         pc[7] = m8 = p2*x7 + p5*x8 + p8*x9;
2338         pc[8] = m9 = p3*x7 + p6*x8 + p9*x9;
2339 
2340         nz = bi[row+1] - diag_offset[row] - 1;
2341         pv += 9;
2342         for (j=0; j<nz; j++) {
2343           x1   = pv[0];  x2  = pv[1];   x3 = pv[2];  x4  = pv[3];
2344           x5   = pv[4];  x6  = pv[5];   x7 = pv[6];  x8  = pv[7]; x9 = pv[8];
2345           x    = rtmp + 9*pj[j];
2346           x[0] -= m1*x1 + m4*x2 + m7*x3;
2347           x[1] -= m2*x1 + m5*x2 + m8*x3;
2348           x[2] -= m3*x1 + m6*x2 + m9*x3;
2349 
2350           x[3] -= m1*x4 + m4*x5 + m7*x6;
2351           x[4] -= m2*x4 + m5*x5 + m8*x6;
2352           x[5] -= m3*x4 + m6*x5 + m9*x6;
2353 
2354           x[6] -= m1*x7 + m4*x8 + m7*x9;
2355           x[7] -= m2*x7 + m5*x8 + m8*x9;
2356           x[8] -= m3*x7 + m6*x8 + m9*x9;
2357           pv   += 9;
2358         }
2359         PLogFlops(54*nz+36);
2360       }
2361       row = *ajtmp++;
2362     }
2363     /* finished row so stick it into b->a */
2364     pv = ba + 9*bi[i];
2365     pj = bj + bi[i];
2366     nz = bi[i+1] - bi[i];
2367     for (j=0; j<nz; j++) {
2368       x      = rtmp+9*pj[j];
2369       pv[0]  = x[0];  pv[1]  = x[1];  pv[2]  = x[2];  pv[3]  = x[3];
2370       pv[4]  = x[4];  pv[5]  = x[5];  pv[6]  = x[6];  pv[7]  = x[7]; pv[8] = x[8];
2371       pv   += 9;
2372     }
2373     /* invert diagonal block */
2374     w = ba + 9*diag_offset[i];
2375     ierr = Kernel_A_gets_inverse_A_3(w);CHKERRQ(ierr);
2376   }
2377 
2378   ierr = PetscFree(rtmp);CHKERRQ(ierr);
2379   C->factor    = FACTOR_CHOLESKY;
2380   C->assembled = PETSC_TRUE;
2381   C->preallocated = PETSC_TRUE;
2382   PLogFlops(1.3333*27*b->mbs); /* from inverting diagonal blocks */
2383   PetscFunctionReturn(0);
2384 }
2385 
2386 /*
2387     Numeric U^T*D*U factorization for SBAIJ format. Modified from SNF of YSMP.
2388     Version for blocks 2 by 2.
2389 */
2390 #undef __FUNC__
2391 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_2"
2392 int MatCholeskyFactorNumeric_SeqSBAIJ_2(Mat A,Mat *B)
2393 {
2394   Mat                C = *B;
2395   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
2396   IS                 perm = b->row;
2397   int                *perm_ptr,ierr,i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
2398   int                *ai,*aj,*a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
2399   MatScalar          *ba = b->a,*aa,*ap,*dk,*uik;
2400   MatScalar          *u,*diag,*rtmp,*rtmp_ptr;
2401 
2402   PetscFunctionBegin;
2403 
2404   /* initialization */
2405   /* il and jl record the first nonzero element in each row of the accessing
2406      window U(0:k, k:mbs-1).
2407      jl:    list of rows to be added to uneliminated rows
2408             i>= k: jl(i) is the first row to be added to row i
2409             i<  k: jl(i) is the row following row i in some list of rows
2410             jl(i) = mbs indicates the end of a list
2411      il(i): points to the first nonzero element in columns k,...,mbs-1 of
2412             row i of U */
2413   rtmp  = (MatScalar*)PetscMalloc(4*mbs*sizeof(MatScalar));CHKPTRQ(rtmp);
2414   ierr = PetscMemzero(rtmp,4*mbs*sizeof(MatScalar));CHKERRQ(ierr);
2415   il = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(il);
2416   jl = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(jl);
2417   for (i=0; i<mbs; i++) {
2418     jl[i] = mbs; il[0] = 0;
2419   }
2420   dk  = (MatScalar*)PetscMalloc(4*sizeof(MatScalar));CHKPTRQ(dk);
2421   uik = (MatScalar*)PetscMalloc(4*sizeof(MatScalar));CHKPTRQ(uik);
2422   ierr  = ISGetIndices(perm,&perm_ptr);CHKERRQ(ierr);
2423 
2424   /* check permutation */
2425   if (!a->permute){
2426     ai = a->i; aj = a->j; aa = a->a;
2427   } else {
2428     ai = a->inew; aj = a->jnew;
2429     aa = (MatScalar*)PetscMalloc(4*ai[mbs]*sizeof(MatScalar));CHKPTRQ(aa);
2430     ierr = PetscMemcpy(aa,a->a,4*ai[mbs]*sizeof(MatScalar));CHKERRQ(ierr);
2431     a2anew  = (int*)PetscMalloc(ai[mbs]*sizeof(int));CHKPTRQ(a2anew);
2432     ierr= PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(int));CHKERRQ(ierr);
2433 
2434     for (i=0; i<mbs; i++){
2435       jmin = ai[i]; jmax = ai[i+1];
2436       for (j=jmin; j<jmax; j++){
2437         while (a2anew[j] != j){
2438           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
2439           for (k1=0; k1<4; k1++){
2440             dk[k1]       = aa[k*4+k1];
2441             aa[k*4+k1] = aa[j*4+k1];
2442             aa[j*4+k1] = dk[k1];
2443           }
2444         }
2445         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
2446         if (i > aj[j]){
2447           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
2448           ap = aa + j*4;     /* ptr to the beginning of the block */
2449           dk[1] = ap[1];     /* swap ap[1] and ap[2] */
2450           ap[1] = ap[2];
2451           ap[2] = dk[1];
2452         }
2453       }
2454     }
2455     ierr = PetscFree(a2anew);CHKERRA(ierr);
2456   }
2457 
2458   /* for each row k */
2459   for (k = 0; k<mbs; k++){
2460 
2461     /*initialize k-th row with elements nonzero in row perm(k) of A */
2462     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];
2463     if (jmin < jmax) {
2464       ap = aa + jmin*4;
2465       for (j = jmin; j < jmax; j++){
2466         vj = perm_ptr[aj[j]];         /* block col. index */
2467         rtmp_ptr = rtmp + vj*4;
2468         for (i=0; i<4; i++) *rtmp_ptr++ = *ap++;
2469       }
2470     }
2471 
2472     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
2473     ierr = PetscMemcpy(dk,rtmp+k*4,4*sizeof(MatScalar));CHKERRQ(ierr);
2474     i = jl[k]; /* first row to be added to k_th row  */
2475 
2476     while (i < mbs){
2477       nexti = jl[i]; /* next row to be added to k_th row */
2478 
2479       /* compute multiplier */
2480       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
2481 
2482       /* uik = -inv(Di)*U_bar(i,k): - ba[ili]*ba[i] */
2483       diag = ba + i*4;
2484       u    = ba + ili*4;
2485       uik[0] = -(diag[0]*u[0] + diag[2]*u[1]);
2486       uik[1] = -(diag[1]*u[0] + diag[3]*u[1]);
2487       uik[2] = -(diag[0]*u[2] + diag[2]*u[3]);
2488       uik[3] = -(diag[1]*u[2] + diag[3]*u[3]);
2489 
2490       /* update D(k) += -U(i,k)^T * U_bar(i,k): dk += uik*ba[ili] */
2491       dk[0] += uik[0]*u[0] + uik[1]*u[1];
2492       dk[1] += uik[2]*u[0] + uik[3]*u[1];
2493       dk[2] += uik[0]*u[2] + uik[1]*u[3];
2494       dk[3] += uik[2]*u[2] + uik[3]*u[3];
2495 
2496       /* update -U(i,k): ba[ili] = uik */
2497       ierr = PetscMemcpy(ba+ili*4,uik,4*sizeof(MatScalar));CHKERRQ(ierr);
2498 
2499       /* add multiple of row i to k-th row ... */
2500       jmin = ili + 1; jmax = bi[i+1];
2501       if (jmin < jmax){
2502         for (j=jmin; j<jmax; j++) {
2503           /* rtmp += -U(i,k)^T * U_bar(i,j): rtmp[bj[j]] += uik*ba[j]; */
2504           rtmp_ptr = rtmp + bj[j]*4;
2505           u = ba + j*4;
2506           rtmp_ptr[0] += uik[0]*u[0] + uik[1]*u[1];
2507           rtmp_ptr[1] += uik[2]*u[0] + uik[3]*u[1];
2508           rtmp_ptr[2] += uik[0]*u[2] + uik[1]*u[3];
2509           rtmp_ptr[3] += uik[2]*u[2] + uik[3]*u[3];
2510         }
2511 
2512         /* ... add i to row list for next nonzero entry */
2513         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
2514         j     = bj[jmin];
2515         jl[i] = jl[j]; jl[j] = i; /* update jl */
2516       }
2517       i = nexti;
2518     }
2519 
2520     /* save nonzero entries in k-th row of U ... */
2521 
2522     /* invert diagonal block */
2523     diag = ba+k*4;
2524     ierr = PetscMemcpy(diag,dk,4*sizeof(MatScalar));CHKERRQ(ierr);
2525     ierr = Kernel_A_gets_inverse_A_2(diag);CHKERRQ(ierr);
2526 
2527     jmin = bi[k]; jmax = bi[k+1];
2528     if (jmin < jmax) {
2529       for (j=jmin; j<jmax; j++){
2530          vj = bj[j];           /* block col. index of U */
2531          u   = ba + j*4;
2532          rtmp_ptr = rtmp + vj*4;
2533          for (k1=0; k1<4; k1++){
2534            *u++        = *rtmp_ptr;
2535            *rtmp_ptr++ = 0.0;
2536          }
2537       }
2538 
2539       /* ... add k to row list for first nonzero entry in k-th row */
2540       il[k] = jmin;
2541       i     = bj[jmin];
2542       jl[k] = jl[i]; jl[i] = k;
2543     }
2544   }
2545 
2546   ierr = PetscFree(rtmp);CHKERRQ(ierr);
2547   ierr = PetscFree(il);CHKERRQ(ierr);
2548   ierr = PetscFree(jl);CHKERRQ(ierr);
2549   ierr = PetscFree(dk);CHKERRQ(ierr);
2550   ierr = PetscFree(uik);CHKERRQ(ierr);
2551   if (a->permute){
2552     ierr = PetscFree(aa);CHKERRQ(ierr);
2553   }
2554 
2555   ierr = ISRestoreIndices(perm,&perm_ptr);CHKERRQ(ierr);
2556   C->factor    = FACTOR_CHOLESKY;
2557   C->assembled = PETSC_TRUE;
2558   C->preallocated = PETSC_TRUE;
2559   PLogFlops(1.3333*8*b->mbs); /* from inverting diagonal blocks */
2560   PetscFunctionReturn(0);
2561 }
2562 
2563 /*
2564       Version for when blocks are 2 by 2 Using natural ordering
2565 */
2566 #undef __FUNC__
2567 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_2_NaturalOrdering"
2568 int MatCholeskyFactorNumeric_SeqSBAIJ_2_NaturalOrdering(Mat A,Mat *B)
2569 {
2570   Mat                C = *B;
2571   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
2572   int                ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
2573   int                *ajtmpold,*ajtmp,nz,row;
2574   int                *diag_offset = b->diag,*ai=a->i,*aj=a->j,*pj;
2575   MatScalar          *pv,*v,*rtmp,*pc,*w,*x;
2576   MatScalar          p1,p2,p3,p4,m1,m2,m3,m4,x1,x2,x3,x4;
2577   MatScalar          *ba = b->a,*aa = a->a;
2578 
2579   PetscFunctionBegin;
2580   rtmp  = (MatScalar*)PetscMalloc(4*(n+1)*sizeof(MatScalar));CHKPTRQ(rtmp);
2581 
2582   for (i=0; i<n; i++) {
2583     nz    = bi[i+1] - bi[i];
2584     ajtmp = bj + bi[i];
2585     for  (j=0; j<nz; j++) {
2586       x = rtmp+4*ajtmp[j];
2587       x[0]  = x[1]  = x[2]  = x[3]  = 0.0;
2588     }
2589     /* load in initial (unfactored row) */
2590     nz       = ai[i+1] - ai[i];
2591     ajtmpold = aj + ai[i];
2592     v        = aa + 4*ai[i];
2593     for (j=0; j<nz; j++) {
2594       x    = rtmp+4*ajtmpold[j];
2595       x[0]  = v[0];  x[1]  = v[1];  x[2]  = v[2];  x[3]  = v[3];
2596       v    += 4;
2597     }
2598     row = *ajtmp++;
2599     while (row < i) {
2600       pc  = rtmp + 4*row;
2601       p1  = pc[0];  p2  = pc[1];  p3  = pc[2];  p4  = pc[3];
2602       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0) {
2603         pv = ba + 4*diag_offset[row];
2604         pj = bj + diag_offset[row] + 1;
2605         x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
2606         pc[0] = m1 = p1*x1 + p3*x2;
2607         pc[1] = m2 = p2*x1 + p4*x2;
2608         pc[2] = m3 = p1*x3 + p3*x4;
2609         pc[3] = m4 = p2*x3 + p4*x4;
2610         nz = bi[row+1] - diag_offset[row] - 1;
2611         pv += 4;
2612         for (j=0; j<nz; j++) {
2613           x1   = pv[0];  x2  = pv[1];   x3 = pv[2];  x4  = pv[3];
2614           x    = rtmp + 4*pj[j];
2615           x[0] -= m1*x1 + m3*x2;
2616           x[1] -= m2*x1 + m4*x2;
2617           x[2] -= m1*x3 + m3*x4;
2618           x[3] -= m2*x3 + m4*x4;
2619           pv   += 4;
2620         }
2621         PLogFlops(16*nz+12);
2622       }
2623       row = *ajtmp++;
2624     }
2625     /* finished row so stick it into b->a */
2626     pv = ba + 4*bi[i];
2627     pj = bj + bi[i];
2628     nz = bi[i+1] - bi[i];
2629     for (j=0; j<nz; j++) {
2630       x      = rtmp+4*pj[j];
2631       pv[0]  = x[0];  pv[1]  = x[1];  pv[2]  = x[2];  pv[3]  = x[3];
2632       pv   += 4;
2633     }
2634     /* invert diagonal block */
2635     w = ba + 4*diag_offset[i];
2636     ierr = Kernel_A_gets_inverse_A_2(w);CHKERRQ(ierr);
2637     /*Kernel_A_gets_inverse_A(bs,w,v_pivots,v_work);*/
2638   }
2639 
2640   ierr = PetscFree(rtmp);CHKERRQ(ierr);
2641   C->factor    = FACTOR_LU;
2642   C->assembled = PETSC_TRUE;
2643   C->preallocated = PETSC_TRUE;
2644   PLogFlops(1.3333*8*b->mbs); /* from inverting diagonal blocks */
2645   PetscFunctionReturn(0);
2646 }
2647 
2648 /*
2649     Numeric U^T*D*U factorization for SBAIJ format. Modified from SNF of YSMP.
2650     Version for blocks are 1 by 1.
2651 */
2652 #undef __FUNC__
2653 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_1"
2654 int MatCholeskyFactorNumeric_SeqSBAIJ_1(Mat A,Mat *B)
2655 {
2656   Mat                C = *B;
2657   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
2658   IS                 ip = b->row;
2659   int                *rip,ierr,i,j,mbs = a->mbs,*bi = b->i,*bj = b->j;
2660   int                *ai,*aj,*r;
2661   MatScalar          *rtmp;
2662   MatScalar          *ba = b->a,*aa,ak;
2663   MatScalar          dk,uikdi;
2664   int                k,jmin,jmax,*jl,*il,vj,nexti,ili;
2665 
2666   PetscFunctionBegin;
2667   ierr  = ISGetIndices(ip,&rip);CHKERRQ(ierr);
2668   if (!a->permute){
2669     ai = a->i; aj = a->j; aa = a->a;
2670   } else {
2671     ai = a->inew; aj = a->jnew;
2672     aa = (MatScalar*)PetscMalloc(ai[mbs]*sizeof(MatScalar));CHKPTRQ(aa);
2673     ierr = PetscMemcpy(aa,a->a,ai[mbs]*sizeof(MatScalar));CHKERRQ(ierr);
2674     r   = (int*)PetscMalloc(ai[mbs]*sizeof(int));CHKPTRQ(r);
2675     ierr= PetscMemcpy(r,a->a2anew,(ai[mbs])*sizeof(int));CHKERRQ(ierr);
2676 
2677     jmin = ai[0]; jmax = ai[mbs];
2678     for (j=jmin; j<jmax; j++){
2679       while (r[j] != j){
2680         k = r[j]; r[j] = r[k]; r[k] = k;
2681         ak = aa[k]; aa[k] = aa[j]; aa[j] = ak;
2682       }
2683     }
2684     ierr = PetscFree(r);CHKERRA(ierr);
2685   }
2686 
2687   /* initialization */
2688   /* il and jl record the first nonzero element in each row of the accessing
2689      window U(0:k, k:mbs-1).
2690      jl:    list of rows to be added to uneliminated rows
2691             i>= k: jl(i) is the first row to be added to row i
2692             i<  k: jl(i) is the row following row i in some list of rows
2693             jl(i) = mbs indicates the end of a list
2694      il(i): points to the first nonzero element in columns k,...,mbs-1 of
2695             row i of U */
2696   rtmp  = (MatScalar*)PetscMalloc(mbs*sizeof(MatScalar));CHKPTRQ(rtmp);
2697   il = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(il);
2698   jl = (int*)PetscMalloc(mbs*sizeof(int));CHKPTRQ(jl);
2699   for (i=0; i<mbs; i++) {
2700     rtmp[i] = 0.0; jl[i] = mbs; il[0] = 0;
2701   }
2702 
2703   /* for each row k */
2704   for (k = 0; k<mbs; k++){
2705 
2706     /*initialize k-th row with elements nonzero in row perm(k) of A */
2707     jmin = ai[rip[k]]; jmax = ai[rip[k]+1];
2708     if (jmin < jmax) {
2709       for (j = jmin; j < jmax; j++){
2710         vj = rip[aj[j]];
2711         /* if (k <= vj)*/ rtmp[vj] = aa[j];
2712       }
2713     }
2714 
2715     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
2716     dk = rtmp[k];
2717     i = jl[k]; /* first row to be added to k_th row  */
2718     /* printf(" k=%d, pivot row = %d\n",k,i); */
2719 
2720     while (i < mbs){
2721       nexti = jl[i]; /* next row to be added to k_th row */
2722 
2723       /* compute multiplier, update D(k) and U(i,k) */
2724       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
2725       uikdi = - ba[ili]*ba[i];
2726       dk += uikdi*ba[ili];
2727       ba[ili] = uikdi; /* -U(i,k) */
2728 
2729       /* add multiple of row i to k-th row ... */
2730       jmin = ili + 1; jmax = bi[i+1];
2731       if (jmin < jmax){
2732         for (j=jmin; j<jmax; j++) rtmp[bj[j]] += uikdi*ba[j];
2733         /* ... add i to row list for next nonzero entry */
2734         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
2735         j     = bj[jmin];
2736         jl[i] = jl[j]; jl[j] = i; /* update jl */
2737       }
2738       i = nexti; /* printf("                  pivot row i=%d\n",i);  */
2739     }
2740 
2741     /* check for zero pivot and save diagoanl element */
2742     if (dk == 0.0){
2743       SETERRQ(PETSC_ERR_MAT_LU_ZRPVT,"Zero pivot");
2744     }else if (PetscRealPart(dk) < 0){
2745       ierr = PetscPrintf(PETSC_COMM_SELF,"Negative pivot: d[%d] = %g\n",k,dk);
2746     }
2747 
2748     /* save nonzero entries in k-th row of U ... */
2749     ba[k] = 1.0/dk;
2750     jmin = bi[k]; jmax = bi[k+1];
2751     if (jmin < jmax) {
2752       for (j=jmin; j<jmax; j++){
2753          vj = bj[j]; ba[j] = rtmp[vj]; rtmp[vj] = 0.0;
2754       }
2755       /* ... add k to row list for first nonzero entry in k-th row */
2756       il[k] = jmin;
2757       i     = bj[jmin];
2758       jl[k] = jl[i]; jl[i] = k;
2759     }
2760   }
2761 
2762   ierr = PetscFree(rtmp);CHKERRQ(ierr);
2763   ierr = PetscFree(il);CHKERRQ(ierr);
2764   ierr = PetscFree(jl);CHKERRQ(ierr);
2765   if (a->permute){
2766     ierr = PetscFree(aa);CHKERRQ(ierr);
2767   }
2768 
2769   ierr = ISRestoreIndices(ip,&rip);CHKERRQ(ierr);
2770   C->factor    = FACTOR_CHOLESKY;
2771   C->assembled = PETSC_TRUE;
2772   C->preallocated = PETSC_TRUE;
2773   PLogFlops(b->mbs);
2774 #ifdef TEMP
2775   printf("in factnum_1\n");
2776   for (k=0; k<mbs; k++){
2777     i = b->i[k+1] - b->i[k];
2778     printf("\n b->i[%d]: %d, nzk: %d, diag: %g\n",k,b->i[k],i,b->a[k]);
2779     jmin = b->i[k]; jmax = b->i[k+1];
2780     for (j=jmin; j<jmax; j++){
2781       printf(" %d %g, ",b->j[j],b->a[j]);
2782     }
2783   }
2784 #endif
2785   PetscFunctionReturn(0);
2786 }
2787 
2788 #undef __FUNC__
2789 #define __FUNC__ "MatCholeskyFactor_SeqSBAIJ"
2790 int MatCholeskyFactor_SeqSBAIJ(Mat A,IS perm,PetscReal f)
2791 {
2792   int ierr;
2793   Mat C;
2794 
2795   PetscFunctionBegin;
2796   ierr = MatCholeskyFactorSymbolic(A,perm,f,&C);CHKERRQ(ierr);
2797   ierr = MatCholeskyFactorNumeric(A,&C);CHKERRQ(ierr);
2798   ierr = MatHeaderCopy(A,C);CHKERRQ(ierr);
2799   PetscFunctionReturn(0);
2800 }
2801 
2802 
2803