xref: /petsc/src/mat/impls/sbaij/seq/sbaijfact6.c (revision a4efd8ea4bb0600a5aef92b2c23cbfa314827193)
1 #define PETSCMAT_DLL
2 
3 #include "src/mat/impls/sbaij/seq/sbaij.h"
4 #include "src/inline/ilu.h"
5 
6 /* Version for when blocks are 4 by 4  */
7 #undef __FUNCT__
8 #define __FUNCT__ "MatCholeskyFactorNumeric_SeqSBAIJ_4"
9 PetscErrorCode MatCholeskyFactorNumeric_SeqSBAIJ_4(Mat A,MatFactorInfo *info,Mat *B)
10 {
11   Mat            C = *B;
12   Mat_SeqSBAIJ   *a = (Mat_SeqSBAIJ*)A->data,*b = (Mat_SeqSBAIJ *)C->data;
13   IS             perm = b->row;
14   PetscErrorCode ierr;
15   PetscInt       *perm_ptr,i,j,mbs=a->mbs,*bi=b->i,*bj=b->j;
16   PetscInt       *ai,*aj,*a2anew,k,k1,jmin,jmax,*jl,*il,vj,nexti,ili;
17   MatScalar      *ba = b->a,*aa,*ap,*dk,*uik;
18   MatScalar      *u,*diag,*rtmp,*rtmp_ptr;
19   PetscTruth     pivotinblocks = b->pivotinblocks;
20   PetscReal      shift = info->shiftinblocks;
21 
22   PetscFunctionBegin;
23   /* initialization */
24   ierr = PetscMalloc(16*mbs*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
25   ierr = PetscMemzero(rtmp,16*mbs*sizeof(MatScalar));CHKERRQ(ierr);
26   ierr = PetscMalloc(2*mbs*sizeof(PetscInt),&il);CHKERRQ(ierr);
27   jl   = il + mbs;
28   for (i=0; i<mbs; i++) {
29     jl[i] = mbs; il[0] = 0;
30   }
31   ierr = PetscMalloc(32*sizeof(MatScalar),&dk);CHKERRQ(ierr);
32   uik  = dk + 16;
33   ierr = ISGetIndices(perm,&perm_ptr);CHKERRQ(ierr);
34 
35   /* check permutation */
36   if (!a->permute){
37     ai = a->i; aj = a->j; aa = a->a;
38   } else {
39     ai   = a->inew; aj = a->jnew;
40     ierr = PetscMalloc(16*ai[mbs]*sizeof(MatScalar),&aa);CHKERRQ(ierr);
41     ierr = PetscMemcpy(aa,a->a,16*ai[mbs]*sizeof(MatScalar));CHKERRQ(ierr);
42     ierr = PetscMalloc(ai[mbs]*sizeof(PetscInt),&a2anew);CHKERRQ(ierr);
43     ierr = PetscMemcpy(a2anew,a->a2anew,(ai[mbs])*sizeof(PetscInt));CHKERRQ(ierr);
44 
45     for (i=0; i<mbs; i++){
46       jmin = ai[i]; jmax = ai[i+1];
47       for (j=jmin; j<jmax; j++){
48         while (a2anew[j] != j){
49           k = a2anew[j]; a2anew[j] = a2anew[k]; a2anew[k] = k;
50           for (k1=0; k1<16; k1++){
51             dk[k1]       = aa[k*16+k1];
52             aa[k*16+k1] = aa[j*16+k1];
53             aa[j*16+k1] = dk[k1];
54           }
55         }
56         /* transform columnoriented blocks that lie in the lower triangle to roworiented blocks */
57         if (i > aj[j]){
58           /* printf("change orientation, row: %d, col: %d\n",i,aj[j]); */
59           ap = aa + j*16;                     /* ptr to the beginning of j-th block of aa */
60           for (k=0; k<16; k++) dk[k] = ap[k]; /* dk <- j-th block of aa */
61           for (k=0; k<4; k++){               /* j-th block of aa <- dk^T */
62             for (k1=0; k1<4; k1++) *ap++ = dk[k + 4*k1];
63           }
64         }
65       }
66     }
67     ierr = PetscFree(a2anew);CHKERRQ(ierr);
68   }
69 
70   /* for each row k */
71   for (k = 0; k<mbs; k++){
72 
73     /*initialize k-th row with elements nonzero in row perm(k) of A */
74     jmin = ai[perm_ptr[k]]; jmax = ai[perm_ptr[k]+1];
75     if (jmin < jmax) {
76       ap = aa + jmin*16;
77       for (j = jmin; j < jmax; j++){
78         vj = perm_ptr[aj[j]];         /* block col. index */
79         rtmp_ptr = rtmp + vj*16;
80         for (i=0; i<16; i++) *rtmp_ptr++ = *ap++;
81       }
82     }
83 
84     /* modify k-th row by adding in those rows i with U(i,k) != 0 */
85     ierr = PetscMemcpy(dk,rtmp+k*16,16*sizeof(MatScalar));CHKERRQ(ierr);
86     i = jl[k]; /* first row to be added to k_th row  */
87 
88     while (i < mbs){
89       nexti = jl[i]; /* next row to be added to k_th row */
90 
91       /* compute multiplier */
92       ili = il[i];  /* index of first nonzero element in U(i,k:bms-1) */
93 
94       /* uik = -inv(Di)*U_bar(i,k) */
95       diag = ba + i*16;
96       u    = ba + ili*16;
97 
98       uik[0] = -(diag[0]*u[0] + diag[4]*u[1] + diag[8]*u[2] + diag[12]*u[3]);
99       uik[1] = -(diag[1]*u[0] + diag[5]*u[1] + diag[9]*u[2] + diag[13]*u[3]);
100       uik[2] = -(diag[2]*u[0] + diag[6]*u[1] + diag[10]*u[2]+ diag[14]*u[3]);
101       uik[3] = -(diag[3]*u[0] + diag[7]*u[1] + diag[11]*u[2]+ diag[15]*u[3]);
102 
103       uik[4] = -(diag[0]*u[4] + diag[4]*u[5] + diag[8]*u[6] + diag[12]*u[7]);
104       uik[5] = -(diag[1]*u[4] + diag[5]*u[5] + diag[9]*u[6] + diag[13]*u[7]);
105       uik[6] = -(diag[2]*u[4] + diag[6]*u[5] + diag[10]*u[6]+ diag[14]*u[7]);
106       uik[7] = -(diag[3]*u[4] + diag[7]*u[5] + diag[11]*u[6]+ diag[15]*u[7]);
107 
108       uik[8] = -(diag[0]*u[8] + diag[4]*u[9] + diag[8]*u[10] + diag[12]*u[11]);
109       uik[9] = -(diag[1]*u[8] + diag[5]*u[9] + diag[9]*u[10] + diag[13]*u[11]);
110       uik[10]= -(diag[2]*u[8] + diag[6]*u[9] + diag[10]*u[10]+ diag[14]*u[11]);
111       uik[11]= -(diag[3]*u[8] + diag[7]*u[9] + diag[11]*u[10]+ diag[15]*u[11]);
112 
113       uik[12]= -(diag[0]*u[12] + diag[4]*u[13] + diag[8]*u[14] + diag[12]*u[15]);
114       uik[13]= -(diag[1]*u[12] + diag[5]*u[13] + diag[9]*u[14] + diag[13]*u[15]);
115       uik[14]= -(diag[2]*u[12] + diag[6]*u[13] + diag[10]*u[14]+ diag[14]*u[15]);
116       uik[15]= -(diag[3]*u[12] + diag[7]*u[13] + diag[11]*u[14]+ diag[15]*u[15]);
117 
118       /* update D(k) += -U(i,k)^T * U_bar(i,k) */
119       dk[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
120       dk[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
121       dk[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
122       dk[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
123 
124       dk[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
125       dk[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
126       dk[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
127       dk[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
128 
129       dk[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
130       dk[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
131       dk[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
132       dk[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
133 
134       dk[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
135       dk[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
136       dk[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
137       dk[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
138 
139       ierr = PetscLogFlops(64*4);CHKERRQ(ierr);
140 
141       /* update -U(i,k) */
142       ierr = PetscMemcpy(ba+ili*16,uik,16*sizeof(MatScalar));CHKERRQ(ierr);
143 
144       /* add multiple of row i to k-th row ... */
145       jmin = ili + 1; jmax = bi[i+1];
146       if (jmin < jmax){
147         for (j=jmin; j<jmax; j++) {
148           /* rtmp += -U(i,k)^T * U_bar(i,j) */
149           rtmp_ptr = rtmp + bj[j]*16;
150           u = ba + j*16;
151           rtmp_ptr[0] += uik[0]*u[0] + uik[1]*u[1] + uik[2]*u[2] + uik[3]*u[3];
152           rtmp_ptr[1] += uik[4]*u[0] + uik[5]*u[1] + uik[6]*u[2] + uik[7]*u[3];
153           rtmp_ptr[2] += uik[8]*u[0] + uik[9]*u[1] + uik[10]*u[2]+ uik[11]*u[3];
154           rtmp_ptr[3] += uik[12]*u[0]+ uik[13]*u[1]+ uik[14]*u[2]+ uik[15]*u[3];
155 
156           rtmp_ptr[4] += uik[0]*u[4] + uik[1]*u[5] + uik[2]*u[6] + uik[3]*u[7];
157           rtmp_ptr[5] += uik[4]*u[4] + uik[5]*u[5] + uik[6]*u[6] + uik[7]*u[7];
158           rtmp_ptr[6] += uik[8]*u[4] + uik[9]*u[5] + uik[10]*u[6]+ uik[11]*u[7];
159           rtmp_ptr[7] += uik[12]*u[4]+ uik[13]*u[5]+ uik[14]*u[6]+ uik[15]*u[7];
160 
161           rtmp_ptr[8] += uik[0]*u[8] + uik[1]*u[9] + uik[2]*u[10] + uik[3]*u[11];
162           rtmp_ptr[9] += uik[4]*u[8] + uik[5]*u[9] + uik[6]*u[10] + uik[7]*u[11];
163           rtmp_ptr[10]+= uik[8]*u[8] + uik[9]*u[9] + uik[10]*u[10]+ uik[11]*u[11];
164           rtmp_ptr[11]+= uik[12]*u[8]+ uik[13]*u[9]+ uik[14]*u[10]+ uik[15]*u[11];
165 
166           rtmp_ptr[12]+= uik[0]*u[12] + uik[1]*u[13] + uik[2]*u[14] + uik[3]*u[15];
167           rtmp_ptr[13]+= uik[4]*u[12] + uik[5]*u[13] + uik[6]*u[14] + uik[7]*u[15];
168           rtmp_ptr[14]+= uik[8]*u[12] + uik[9]*u[13] + uik[10]*u[14]+ uik[11]*u[15];
169           rtmp_ptr[15]+= uik[12]*u[12]+ uik[13]*u[13]+ uik[14]*u[14]+ uik[15]*u[15];
170         }
171         ierr = PetscLogFlops(2*64*(jmax-jmin));CHKERRQ(ierr);
172 
173         /* ... add i to row list for next nonzero entry */
174         il[i] = jmin;             /* update il(i) in column k+1, ... mbs-1 */
175         j     = bj[jmin];
176         jl[i] = jl[j]; jl[j] = i; /* update jl */
177       }
178       i = nexti;
179     }
180 
181     /* save nonzero entries in k-th row of U ... */
182 
183     /* invert diagonal block */
184     diag = ba+k*16;
185     ierr = PetscMemcpy(diag,dk,16*sizeof(MatScalar));CHKERRQ(ierr);
186 
187     if (pivotinblocks) {
188       ierr = Kernel_A_gets_inverse_A_4(diag,shift);CHKERRQ(ierr);
189     } else {
190       ierr = Kernel_A_gets_inverse_A_4_nopivot(diag);CHKERRQ(ierr);
191     }
192 
193     jmin = bi[k]; jmax = bi[k+1];
194     if (jmin < jmax) {
195       for (j=jmin; j<jmax; j++){
196          vj = bj[j];           /* block col. index of U */
197          u   = ba + j*16;
198          rtmp_ptr = rtmp + vj*16;
199          for (k1=0; k1<16; k1++){
200            *u++        = *rtmp_ptr;
201            *rtmp_ptr++ = 0.0;
202          }
203       }
204 
205       /* ... add k to row list for first nonzero entry in k-th row */
206       il[k] = jmin;
207       i     = bj[jmin];
208       jl[k] = jl[i]; jl[i] = k;
209     }
210   }
211 
212   ierr = PetscFree(rtmp);CHKERRQ(ierr);
213   ierr = PetscFree(il);CHKERRQ(ierr);
214   ierr = PetscFree(dk);CHKERRQ(ierr);
215   if (a->permute){
216     ierr = PetscFree(aa);CHKERRQ(ierr);
217   }
218 
219   ierr = ISRestoreIndices(perm,&perm_ptr);CHKERRQ(ierr);
220   C->ops->solve          = MatSolve_SeqSBAIJ_4;
221   C->ops->solvetranspose = MatSolve_SeqSBAIJ_4;
222   C->assembled = PETSC_TRUE;
223   C->preallocated = PETSC_TRUE;
224   ierr = PetscLogFlops(1.3333*64*b->mbs);CHKERRQ(ierr); /* from inverting diagonal blocks */
225   PetscFunctionReturn(0);
226 }
227