xref: /petsc/src/mat/impls/sbaij/seq/sbaijfact6.c (revision f2a5309cf2bd60e875de7457ab3728dd4e42fdc5)
1 #include "sbaij.h"
2 #include "src/inline/ilu.h"
3 
4 /* Version for when blocks are 4 by 4  */
5 #undef __FUNC__
6 #define __FUNC__ "MatCholeskyFactorNumeric_SeqSBAIJ_4"
7 int MatCholeskyFactorNumeric_SeqSBAIJ_4(Mat A,Mat *B)
8 {
9   Mat                C = *B;
10   Mat_SeqSBAIJ       *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
11   IS                 perm = b->row;
12   int                *perm_ptr,ierr,i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
13   int                *ai,*aj,*a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
14   MatScalar          *ba = b->a,*aa,*ap,*dk,*uik;
15   MatScalar          *u,*diag,*rtmp,*rtmp_ptr;
16 
17   PetscFunctionBegin;
18   /* initialization */
19   ierr = PetscMalloc(16*mbs*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
20   ierr = PetscMemzero(rtmp,16*mbs*sizeof(MatScalar));CHKERRQ(ierr);
21   ierr = PetscMalloc(2*mbs*sizeof(int),&il);CHKERRQ(ierr);
22   jl   = il + mbs;
23   for (i=0; i<mbs; i++) {
24     jl[i] = mbs; il[0] = 0;
25   }
26   ierr = PetscMalloc(32*sizeof(MatScalar),&dk);CHKERRQ(ierr);
27   uik  = dk + 16;
28   ierr = ISGetIndices(perm,&perm_ptr);CHKERRQ(ierr);
29 
30   /* check permutation */
31   if (!a->permute){
32     ai = a->i; aj = a->j; aa = a->a;
33   } else {
34     ai   = a->inew; aj = a->jnew;
35     ierr = PetscMalloc(16*ai[mbs]*sizeof(MatScalar),&aa);CHKERRQ(ierr);
36     ierr = PetscMemcpy(aa,a->a,16*ai[mbs]*sizeof(MatScalar));CHKERRQ(ierr);
37     ierr = PetscMalloc(ai[mbs]*sizeof(int),&a2anew);CHKERRQ(ierr);
38     ierr = PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(int));CHKERRQ(ierr);
39 
40     for (i=0; i<mbs; i++){
41       jmin = ai[i]; jmax = ai[i+1];
42       for (j=jmin; j<jmax; j++){
43         while (a2anew[j] != j){
44           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
45           for (k1=0; k1<16; k1++){
46             dk[k1]       = aa[k*16+k1];
47             aa[k*16+k1] = aa[j*16+k1];
48             aa[j*16+k1] = dk[k1];
49           }
50         }
51         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
52         if (i > aj[j]){
53           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
54           ap = aa + j*16;                     /* ptr to the beginning of j-th block of aa */
55           for (k=0; k<16; k++) dk[k] = ap[k]; /* dk <- j-th block of aa */
56           for (k=0; k<4; k++){               /* j-th block of aa <- dk^T */
57             for (k1=0; k1<4; k1++) *ap++ = dk[k + 4*k1];
58           }
59         }
60       }
61     }
62     ierr = PetscFree(a2anew);CHKERRQ(ierr);
63   }
64 
65   /* for each row k */
66   for (k = 0; k<mbs; k++){
67 
68     /*initialize k-th row with elements nonzero in row perm(k) of A */
69     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];
70     if (jmin < jmax) {
71       ap = aa + jmin*16;
72       for (j = jmin; j < jmax; j++){
73         vj = perm_ptr[aj[j]];         /* block col. index */
74         rtmp_ptr = rtmp + vj*16;
75         for (i=0; i<16; i++) *rtmp_ptr++ = *ap++;
76       }
77     }
78 
79     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
80     ierr = PetscMemcpy(dk,rtmp+k*16,16*sizeof(MatScalar));CHKERRQ(ierr);
81     i = jl[k]; /* first row to be added to k_th row  */
82 
83     while (i < mbs){
84       nexti = jl[i]; /* next row to be added to k_th row */
85 
86       /* compute multiplier */
87       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
88 
89       /* uik = -inv(Di)*U_bar(i,k) */
90       diag = ba + i*16;
91       u    = ba + ili*16;
92 
93       uik[0] = -(diag[0]*u[0] + diag[4]*u[1] + diag[8]*u[2] + diag[12]*u[3]);
94       uik[1] = -(diag[1]*u[0] + diag[5]*u[1] + diag[9]*u[2] + diag[13]*u[3]);
95       uik[2] = -(diag[2]*u[0] + diag[6]*u[1] + diag[10]*u[2]+ diag[14]*u[3]);
96       uik[3] = -(diag[3]*u[0] + diag[7]*u[1] + diag[11]*u[2]+ diag[15]*u[3]);
97 
98       uik[4] = -(diag[0]*u[4] + diag[4]*u[5] + diag[8]*u[6] + diag[12]*u[7]);
99       uik[5] = -(diag[1]*u[4] + diag[5]*u[5] + diag[9]*u[6] + diag[13]*u[7]);
100       uik[6] = -(diag[2]*u[4] + diag[6]*u[5] + diag[10]*u[6]+ diag[14]*u[7]);
101       uik[7] = -(diag[3]*u[4] + diag[7]*u[5] + diag[11]*u[6]+ diag[15]*u[7]);
102 
103       uik[8] = -(diag[0]*u[8] + diag[4]*u[9] + diag[8]*u[10] + diag[12]*u[11]);
104       uik[9] = -(diag[1]*u[8] + diag[5]*u[9] + diag[9]*u[10] + diag[13]*u[11]);
105       uik[10]= -(diag[2]*u[8] + diag[6]*u[9] + diag[10]*u[10]+ diag[14]*u[11]);
106       uik[11]= -(diag[3]*u[8] + diag[7]*u[9] + diag[11]*u[10]+ diag[15]*u[11]);
107 
108       uik[12]= -(diag[0]*u[12] + diag[4]*u[13] + diag[8]*u[14] + diag[12]*u[15]);
109       uik[13]= -(diag[1]*u[12] + diag[5]*u[13] + diag[9]*u[14] + diag[13]*u[15]);
110       uik[14]= -(diag[2]*u[12] + diag[6]*u[13] + diag[10]*u[14]+ diag[14]*u[15]);
111       uik[15]= -(diag[3]*u[12] + diag[7]*u[13] + diag[11]*u[14]+ diag[15]*u[15]);
112 
113       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
114       dk[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
115       dk[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
116       dk[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
117       dk[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
118 
119       dk[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
120       dk[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
121       dk[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
122       dk[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
123 
124       dk[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
125       dk[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
126       dk[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
127       dk[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
128 
129       dk[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
130       dk[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
131       dk[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
132       dk[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
133 
134       /* update -U(i,k) */
135       ierr = PetscMemcpy(ba+ili*16,uik,16*sizeof(MatScalar));CHKERRQ(ierr);
136 
137       /* add multiple of row i to k-th row ... */
138       jmin = ili + 1; jmax = bi[i+1];
139       if (jmin < jmax){
140         for (j=jmin; j<jmax; j++) {
141           /* rtmp += -U(i,k)^T * U_bar(i,j) */
142           rtmp_ptr = rtmp + bj[j]*16;
143           u = ba + j*16;
144           rtmp_ptr[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
145           rtmp_ptr[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
146           rtmp_ptr[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
147           rtmp_ptr[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
148 
149           rtmp_ptr[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
150           rtmp_ptr[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
151           rtmp_ptr[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
152           rtmp_ptr[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
153 
154           rtmp_ptr[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
155           rtmp_ptr[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
156           rtmp_ptr[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
157           rtmp_ptr[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
158 
159           rtmp_ptr[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
160           rtmp_ptr[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
161           rtmp_ptr[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
162           rtmp_ptr[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
163         }
164 
165         /* ... add i to row list for next nonzero entry */
166         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
167         j     = bj[jmin];
168         jl[i] = jl[j]; jl[j] = i; /* update jl */
169       }
170       i = nexti;
171     }
172 
173     /* save nonzero entries in k-th row of U ... */
174 
175     /* invert diagonal block */
176     diag = ba+k*16;
177     ierr = PetscMemcpy(diag,dk,16*sizeof(MatScalar));CHKERRQ(ierr);
178     ierr = Kernel_A_gets_inverse_A_4(diag);CHKERRQ(ierr);
179 
180     jmin = bi[k]; jmax = bi[k+1];
181     if (jmin < jmax) {
182       for (j=jmin; j<jmax; j++){
183          vj = bj[j];           /* block col. index of U */
184          u   = ba + j*16;
185          rtmp_ptr = rtmp + vj*16;
186          for (k1=0; k1<16; k1++){
187            *u++        = *rtmp_ptr;
188            *rtmp_ptr++ = 0.0;
189          }
190       }
191 
192       /* ... add k to row list for first nonzero entry in k-th row */
193       il[k] = jmin;
194       i     = bj[jmin];
195       jl[k] = jl[i]; jl[i] = k;
196     }
197   }
198 
199   ierr = PetscFree(rtmp);CHKERRQ(ierr);
200   ierr = PetscFree(il);CHKERRQ(ierr);
201   ierr = PetscFree(dk);CHKERRQ(ierr);
202   if (a->permute){
203     ierr = PetscFree(aa);CHKERRQ(ierr);
204   }
205 
206   ierr = ISRestoreIndices(perm,&perm_ptr);CHKERRQ(ierr);
207   C->factor    = FACTOR_CHOLESKY;
208   C->assembled = PETSC_TRUE;
209   C->preallocated = PETSC_TRUE;
210   PetscLogFlops(1.3333*64*b->mbs); /* from inverting diagonal blocks */
211   PetscFunctionReturn(0);
212 }
213