xref: /petsc/src/mat/impls/sbaij/seq/sbaijfact6.c (revision 53e63a63e2b322862e46cb3df41e7eff98a20d20)
1 /*$Id: sbaijfact.c,v 1.56 2001/01/31 19:06:52 balay Exp bsmith $*/
2 #include "sbaij.h"
3 #include "src/inline/ilu.h"
4 
5 /* Version for when blocks are 4 by 4  */
6 #undef __FUNC__
7 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_4"
8 int MatCholeskyFactorNumeric_SeqSBAIJ_4(Mat A,Mat *B)
9 {
10   Mat                C = *B;
11   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
12   IS                 perm = b->row;
13   int                *perm_ptr,ierr,i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
14   int                *ai,*aj,*a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
15   MatScalar          *ba = b->a,*aa,*ap,*dk,*uik;
16   MatScalar          *u,*diag,*rtmp,*rtmp_ptr;
17 
18   PetscFunctionBegin;
19   /* initialization */
20   ierr = PetscMalloc(16*mbs*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
21   ierr = PetscMemzero(rtmp,16*mbs*sizeof(MatScalar));CHKERRQ(ierr);
22   ierr = PetscMalloc(2*mbs*sizeof(int),&il);CHKERRQ(ierr);
23   jl   = il + mbs;
24   for (i=0; i<mbs; i++) {
25     jl[i] = mbs; il[0] = 0;
26   }
27   ierr = PetscMalloc(32*sizeof(MatScalar),&dk);CHKERRQ(ierr);
28   uik  = dk + 16;
29   ierr = ISGetIndices(perm,&perm_ptr);CHKERRQ(ierr);
30 
31   /* check permutation */
32   if (!a->permute){
33     ai = a->i; aj = a->j; aa = a->a;
34   } else {
35     ai   = a->inew; aj = a->jnew;
36     ierr = PetscMalloc(16*ai[mbs]*sizeof(MatScalar),&aa);CHKERRQ(ierr);
37     ierr = PetscMemcpy(aa,a->a,16*ai[mbs]*sizeof(MatScalar));CHKERRQ(ierr);
38     ierr = PetscMalloc(ai[mbs]*sizeof(int),&a2anew);CHKERRQ(ierr);
39     ierr = PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(int));CHKERRQ(ierr);
40 
41     for (i=0; i<mbs; i++){
42       jmin = ai[i]; jmax = ai[i+1];
43       for (j=jmin; j<jmax; j++){
44         while (a2anew[j] != j){
45           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
46           for (k1=0; k1<16; k1++){
47             dk[k1]       = aa[k*16+k1];
48             aa[k*16+k1] = aa[j*16+k1];
49             aa[j*16+k1] = dk[k1];
50           }
51         }
52         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
53         if (i > aj[j]){
54           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
55           ap = aa + j*16;                     /* ptr to the beginning of j-th block of aa */
56           for (k=0; k<16; k++) dk[k] = ap[k]; /* dk <- j-th block of aa */
57           for (k=0; k<4; k++){               /* j-th block of aa <- dk^T */
58             for (k1=0; k1<4; k1++) *ap++ = dk[k + 4*k1];
59           }
60         }
61       }
62     }
63     ierr = PetscFree(a2anew);CHKERRQ(ierr);
64   }
65 
66   /* for each row k */
67   for (k = 0; k<mbs; k++){
68 
69     /*initialize k-th row with elements nonzero in row perm(k) of A */
70     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];
71     if (jmin < jmax) {
72       ap = aa + jmin*16;
73       for (j = jmin; j < jmax; j++){
74         vj = perm_ptr[aj[j]];         /* block col. index */
75         rtmp_ptr = rtmp + vj*16;
76         for (i=0; i<16; i++) *rtmp_ptr++ = *ap++;
77       }
78     }
79 
80     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
81     ierr = PetscMemcpy(dk,rtmp+k*16,16*sizeof(MatScalar));CHKERRQ(ierr);
82     i = jl[k]; /* first row to be added to k_th row  */
83 
84     while (i < mbs){
85       nexti = jl[i]; /* next row to be added to k_th row */
86 
87       /* compute multiplier */
88       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
89 
90       /* uik = -inv(Di)*U_bar(i,k) */
91       diag = ba + i*16;
92       u    = ba + ili*16;
93 
94       uik[0] = -(diag[0]*u[0] + diag[4]*u[1] + diag[8]*u[2] + diag[12]*u[3]);
95       uik[1] = -(diag[1]*u[0] + diag[5]*u[1] + diag[9]*u[2] + diag[13]*u[3]);
96       uik[2] = -(diag[2]*u[0] + diag[6]*u[1] + diag[10]*u[2]+ diag[14]*u[3]);
97       uik[3] = -(diag[3]*u[0] + diag[7]*u[1] + diag[11]*u[2]+ diag[15]*u[3]);
98 
99       uik[4] = -(diag[0]*u[4] + diag[4]*u[5] + diag[8]*u[6] + diag[12]*u[7]);
100       uik[5] = -(diag[1]*u[4] + diag[5]*u[5] + diag[9]*u[6] + diag[13]*u[7]);
101       uik[6] = -(diag[2]*u[4] + diag[6]*u[5] + diag[10]*u[6]+ diag[14]*u[7]);
102       uik[7] = -(diag[3]*u[4] + diag[7]*u[5] + diag[11]*u[6]+ diag[15]*u[7]);
103 
104       uik[8] = -(diag[0]*u[8] + diag[4]*u[9] + diag[8]*u[10] + diag[12]*u[11]);
105       uik[9] = -(diag[1]*u[8] + diag[5]*u[9] + diag[9]*u[10] + diag[13]*u[11]);
106       uik[10]= -(diag[2]*u[8] + diag[6]*u[9] + diag[10]*u[10]+ diag[14]*u[11]);
107       uik[11]= -(diag[3]*u[8] + diag[7]*u[9] + diag[11]*u[10]+ diag[15]*u[11]);
108 
109       uik[12]= -(diag[0]*u[12] + diag[4]*u[13] + diag[8]*u[14] + diag[12]*u[15]);
110       uik[13]= -(diag[1]*u[12] + diag[5]*u[13] + diag[9]*u[14] + diag[13]*u[15]);
111       uik[14]= -(diag[2]*u[12] + diag[6]*u[13] + diag[10]*u[14]+ diag[14]*u[15]);
112       uik[15]= -(diag[3]*u[12] + diag[7]*u[13] + diag[11]*u[14]+ diag[15]*u[15]);
113 
114       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
115       dk[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
116       dk[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
117       dk[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
118       dk[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
119 
120       dk[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
121       dk[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
122       dk[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
123       dk[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
124 
125       dk[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
126       dk[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
127       dk[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
128       dk[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
129 
130       dk[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
131       dk[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
132       dk[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
133       dk[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
134 
135       /* update -U(i,k) */
136       ierr = PetscMemcpy(ba+ili*16,uik,16*sizeof(MatScalar));CHKERRQ(ierr);
137 
138       /* add multiple of row i to k-th row ... */
139       jmin = ili + 1; jmax = bi[i+1];
140       if (jmin < jmax){
141         for (j=jmin; j<jmax; j++) {
142           /* rtmp += -U(i,k)^T * U_bar(i,j) */
143           rtmp_ptr = rtmp + bj[j]*16;
144           u = ba + j*16;
145           rtmp_ptr[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
146           rtmp_ptr[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
147           rtmp_ptr[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
148           rtmp_ptr[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
149 
150           rtmp_ptr[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
151           rtmp_ptr[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
152           rtmp_ptr[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
153           rtmp_ptr[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
154 
155           rtmp_ptr[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
156           rtmp_ptr[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
157           rtmp_ptr[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
158           rtmp_ptr[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
159 
160           rtmp_ptr[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
161           rtmp_ptr[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
162           rtmp_ptr[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
163           rtmp_ptr[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
164         }
165 
166         /* ... add i to row list for next nonzero entry */
167         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
168         j     = bj[jmin];
169         jl[i] = jl[j]; jl[j] = i; /* update jl */
170       }
171       i = nexti;
172     }
173 
174     /* save nonzero entries in k-th row of U ... */
175 
176     /* invert diagonal block */
177     diag = ba+k*16;
178     ierr = PetscMemcpy(diag,dk,16*sizeof(MatScalar));CHKERRQ(ierr);
179     ierr = Kernel_A_gets_inverse_A_4(diag);CHKERRQ(ierr);
180 
181     jmin = bi[k]; jmax = bi[k+1];
182     if (jmin < jmax) {
183       for (j=jmin; j<jmax; j++){
184          vj = bj[j];           /* block col. index of U */
185          u   = ba + j*16;
186          rtmp_ptr = rtmp + vj*16;
187          for (k1=0; k1<16; k1++){
188            *u++        = *rtmp_ptr;
189            *rtmp_ptr++ = 0.0;
190          }
191       }
192 
193       /* ... add k to row list for first nonzero entry in k-th row */
194       il[k] = jmin;
195       i     = bj[jmin];
196       jl[k] = jl[i]; jl[i] = k;
197     }
198   }
199 
200   ierr = PetscFree(rtmp);CHKERRQ(ierr);
201   ierr = PetscFree(il);CHKERRQ(ierr);
202   ierr = PetscFree(dk);CHKERRQ(ierr);
203   if (a->permute){
204     ierr = PetscFree(aa);CHKERRQ(ierr);
205   }
206 
207   ierr = ISRestoreIndices(perm,&perm_ptr);CHKERRQ(ierr);
208   C->factor    = FACTOR_CHOLESKY;
209   C->assembled = PETSC_TRUE;
210   C->preallocated = PETSC_TRUE;
211   PetscLogFlops(1.3333*64*b->mbs); /* from inverting diagonal blocks */
212   PetscFunctionReturn(0);
213 }
214