xref: /petsc/src/mat/impls/baij/seq/baijfact.c (revision 6849ba73f22fecb8f92ef896a42e4e8bd4cd6965)
1 /*
2     Factorization code for BAIJ format.
3 */
4 #include "src/mat/impls/baij/seq/baij.h"
5 #include "src/inline/ilu.h"
6 
7 /* ------------------------------------------------------------*/
8 /*
9       Version for when blocks are 2 by 2
10 */
11 #undef __FUNCT__
12 #define __FUNCT__ "MatLUFactorNumeric_SeqBAIJ_2"
13 PetscErrorCode MatLUFactorNumeric_SeqBAIJ_2(Mat A,Mat *B)
14 {
15   Mat                C = *B;
16   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
17   IS                 isrow = b->row,isicol = b->icol;
18   PetscErrorCode ierr;
19   int                *r,*ic,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
20   int                *ajtmpold,*ajtmp,nz,row;
21   int                *diag_offset=b->diag,idx,*ai=a->i,*aj=a->j,*pj;
22   MatScalar          *pv,*v,*rtmp,m1,m2,m3,m4,*pc,*w,*x,x1,x2,x3,x4;
23   MatScalar          p1,p2,p3,p4;
24   MatScalar          *ba = b->a,*aa = a->a;
25 
26   PetscFunctionBegin;
27   ierr  = ISGetIndices(isrow,&r);CHKERRQ(ierr);
28   ierr  = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
29   ierr  = PetscMalloc(4*(n+1)*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
30 
31   for (i=0; i<n; i++) {
32     nz    = bi[i+1] - bi[i];
33     ajtmp = bj + bi[i];
34     for  (j=0; j<nz; j++) {
35       x = rtmp+4*ajtmp[j]; x[0] = x[1] = x[2] = x[3] = 0.0;
36     }
37     /* load in initial (unfactored row) */
38     idx      = r[i];
39     nz       = ai[idx+1] - ai[idx];
40     ajtmpold = aj + ai[idx];
41     v        = aa + 4*ai[idx];
42     for (j=0; j<nz; j++) {
43       x    = rtmp+4*ic[ajtmpold[j]];
44       x[0] = v[0]; x[1] = v[1]; x[2] = v[2]; x[3] = v[3];
45       v    += 4;
46     }
47     row = *ajtmp++;
48     while (row < i) {
49       pc = rtmp + 4*row;
50       p1 = pc[0]; p2 = pc[1]; p3 = pc[2]; p4 = pc[3];
51       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0) {
52         pv = ba + 4*diag_offset[row];
53         pj = bj + diag_offset[row] + 1;
54         x1 = pv[0]; x2 = pv[1]; x3 = pv[2]; x4 = pv[3];
55         pc[0] = m1 = p1*x1 + p3*x2;
56         pc[1] = m2 = p2*x1 + p4*x2;
57         pc[2] = m3 = p1*x3 + p3*x4;
58         pc[3] = m4 = p2*x3 + p4*x4;
59         nz = bi[row+1] - diag_offset[row] - 1;
60         pv += 4;
61         for (j=0; j<nz; j++) {
62           x1   = pv[0]; x2 = pv[1]; x3 = pv[2]; x4 = pv[3];
63           x    = rtmp + 4*pj[j];
64           x[0] -= m1*x1 + m3*x2;
65           x[1] -= m2*x1 + m4*x2;
66           x[2] -= m1*x3 + m3*x4;
67           x[3] -= m2*x3 + m4*x4;
68           pv   += 4;
69         }
70         PetscLogFlops(16*nz+12);
71       }
72       row = *ajtmp++;
73     }
74     /* finished row so stick it into b->a */
75     pv = ba + 4*bi[i];
76     pj = bj + bi[i];
77     nz = bi[i+1] - bi[i];
78     for (j=0; j<nz; j++) {
79       x     = rtmp+4*pj[j];
80       pv[0] = x[0]; pv[1] = x[1]; pv[2] = x[2]; pv[3] = x[3];
81       pv   += 4;
82     }
83     /* invert diagonal block */
84     w = ba + 4*diag_offset[i];
85     ierr = Kernel_A_gets_inverse_A_2(w);CHKERRQ(ierr);
86   }
87 
88   ierr = PetscFree(rtmp);CHKERRQ(ierr);
89   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
90   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
91   C->factor = FACTOR_LU;
92   C->assembled = PETSC_TRUE;
93   PetscLogFlops(1.3333*8*b->mbs); /* from inverting diagonal blocks */
94   PetscFunctionReturn(0);
95 }
96 /*
97       Version for when blocks are 2 by 2 Using natural ordering
98 */
99 #undef __FUNCT__
100 #define __FUNCT__ "MatLUFactorNumeric_SeqBAIJ_2_NaturalOrdering"
101 PetscErrorCode MatLUFactorNumeric_SeqBAIJ_2_NaturalOrdering(Mat A,Mat *B)
102 {
103   Mat                C = *B;
104   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
105   PetscErrorCode ierr;
106   int  i,j,n = a->mbs,*bi = b->i,*bj = b->j;
107   int                *ajtmpold,*ajtmp,nz,row;
108   int                *diag_offset = b->diag,*ai=a->i,*aj=a->j,*pj;
109   MatScalar          *pv,*v,*rtmp,*pc,*w,*x;
110   MatScalar          p1,p2,p3,p4,m1,m2,m3,m4,x1,x2,x3,x4;
111   MatScalar          *ba = b->a,*aa = a->a;
112 
113   PetscFunctionBegin;
114   ierr = PetscMalloc(4*(n+1)*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
115 
116   for (i=0; i<n; i++) {
117     nz    = bi[i+1] - bi[i];
118     ajtmp = bj + bi[i];
119     for  (j=0; j<nz; j++) {
120       x = rtmp+4*ajtmp[j];
121       x[0]  = x[1]  = x[2]  = x[3]  = 0.0;
122     }
123     /* load in initial (unfactored row) */
124     nz       = ai[i+1] - ai[i];
125     ajtmpold = aj + ai[i];
126     v        = aa + 4*ai[i];
127     for (j=0; j<nz; j++) {
128       x    = rtmp+4*ajtmpold[j];
129       x[0]  = v[0];  x[1]  = v[1];  x[2]  = v[2];  x[3]  = v[3];
130       v    += 4;
131     }
132     row = *ajtmp++;
133     while (row < i) {
134       pc  = rtmp + 4*row;
135       p1  = pc[0];  p2  = pc[1];  p3  = pc[2];  p4  = pc[3];
136       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0) {
137         pv = ba + 4*diag_offset[row];
138         pj = bj + diag_offset[row] + 1;
139         x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
140         pc[0] = m1 = p1*x1 + p3*x2;
141         pc[1] = m2 = p2*x1 + p4*x2;
142         pc[2] = m3 = p1*x3 + p3*x4;
143         pc[3] = m4 = p2*x3 + p4*x4;
144         nz = bi[row+1] - diag_offset[row] - 1;
145         pv += 4;
146         for (j=0; j<nz; j++) {
147           x1   = pv[0];  x2  = pv[1];   x3 = pv[2];  x4  = pv[3];
148           x    = rtmp + 4*pj[j];
149           x[0] -= m1*x1 + m3*x2;
150           x[1] -= m2*x1 + m4*x2;
151           x[2] -= m1*x3 + m3*x4;
152           x[3] -= m2*x3 + m4*x4;
153           pv   += 4;
154         }
155         PetscLogFlops(16*nz+12);
156       }
157       row = *ajtmp++;
158     }
159     /* finished row so stick it into b->a */
160     pv = ba + 4*bi[i];
161     pj = bj + bi[i];
162     nz = bi[i+1] - bi[i];
163     for (j=0; j<nz; j++) {
164       x      = rtmp+4*pj[j];
165       pv[0]  = x[0];  pv[1]  = x[1];  pv[2]  = x[2];  pv[3]  = x[3];
166       pv   += 4;
167     }
168     /* invert diagonal block */
169     w = ba + 4*diag_offset[i];
170     ierr = Kernel_A_gets_inverse_A_2(w);CHKERRQ(ierr);
171     /*Kernel_A_gets_inverse_A(bs,w,v_pivots,v_work);*/
172   }
173 
174   ierr = PetscFree(rtmp);CHKERRQ(ierr);
175   C->factor    = FACTOR_LU;
176   C->assembled = PETSC_TRUE;
177   PetscLogFlops(1.3333*8*b->mbs); /* from inverting diagonal blocks */
178   PetscFunctionReturn(0);
179 }
180 
181 /* ----------------------------------------------------------- */
182 /*
183      Version for when blocks are 1 by 1.
184 */
185 #undef __FUNCT__
186 #define __FUNCT__ "MatLUFactorNumeric_SeqBAIJ_1"
187 PetscErrorCode MatLUFactorNumeric_SeqBAIJ_1(Mat A,Mat *B)
188 {
189   Mat                C = *B;
190   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
191   IS                 isrow = b->row,isicol = b->icol;
192   PetscErrorCode ierr;
193   int                *r,*ic,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
194   int                *ajtmpold,*ajtmp,nz,row,*ai = a->i,*aj = a->j;
195   int                *diag_offset = b->diag,diag,*pj;
196   MatScalar          *pv,*v,*rtmp,multiplier,*pc;
197   MatScalar          *ba = b->a,*aa = a->a;
198 
199   PetscFunctionBegin;
200   ierr  = ISGetIndices(isrow,&r);CHKERRQ(ierr);
201   ierr  = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
202   ierr  = PetscMalloc((n+1)*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
203 
204   for (i=0; i<n; i++) {
205     nz    = bi[i+1] - bi[i];
206     ajtmp = bj + bi[i];
207     for  (j=0; j<nz; j++) rtmp[ajtmp[j]] = 0.0;
208 
209     /* load in initial (unfactored row) */
210     nz       = ai[r[i]+1] - ai[r[i]];
211     ajtmpold = aj + ai[r[i]];
212     v        = aa + ai[r[i]];
213     for (j=0; j<nz; j++) rtmp[ic[ajtmpold[j]]] =  v[j];
214 
215     row = *ajtmp++;
216     while (row < i) {
217       pc = rtmp + row;
218       if (*pc != 0.0) {
219         pv         = ba + diag_offset[row];
220         pj         = bj + diag_offset[row] + 1;
221         multiplier = *pc * *pv++;
222         *pc        = multiplier;
223         nz         = bi[row+1] - diag_offset[row] - 1;
224         for (j=0; j<nz; j++) rtmp[pj[j]] -= multiplier * pv[j];
225         PetscLogFlops(1+2*nz);
226       }
227       row = *ajtmp++;
228     }
229     /* finished row so stick it into b->a */
230     pv = ba + bi[i];
231     pj = bj + bi[i];
232     nz = bi[i+1] - bi[i];
233     for (j=0; j<nz; j++) {pv[j] = rtmp[pj[j]];}
234     diag = diag_offset[i] - bi[i];
235     /* check pivot entry for current row */
236     if (pv[diag] == 0.0) {
237       SETERRQ(PETSC_ERR_MAT_LU_ZRPVT,"Zero pivot");
238     }
239     pv[diag] = 1.0/pv[diag];
240   }
241 
242   ierr = PetscFree(rtmp);CHKERRQ(ierr);
243   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
244   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
245   C->factor    = FACTOR_LU;
246   C->assembled = PETSC_TRUE;
247   PetscLogFlops(C->n);
248   PetscFunctionReturn(0);
249 }
250 
251 
252 /* ----------------------------------------------------------- */
253 #undef __FUNCT__
254 #define __FUNCT__ "MatLUFactor_SeqBAIJ"
255 PetscErrorCode MatLUFactor_SeqBAIJ(Mat A,IS row,IS col,MatFactorInfo *info)
256 {
257   PetscErrorCode ierr;
258   Mat         C;
259 
260   PetscFunctionBegin;
261   ierr = MatLUFactorSymbolic(A,row,col,info,&C);CHKERRQ(ierr);
262   ierr = MatLUFactorNumeric(A,&C);CHKERRQ(ierr);
263   ierr = MatHeaderCopy(A,C);CHKERRQ(ierr);
264   PetscLogObjectParent(A,((Mat_SeqBAIJ*)(A->data))->icol);
265   PetscFunctionReturn(0);
266 }
267 
268 
269