xref: /petsc/src/mat/impls/baij/seq/baijfact.c (revision 4482741e5b2e2bbc854fb1f8dba65221386520f2)
1 /*$Id: baijfact.c,v 1.90 2001/03/23 23:22:07 balay Exp $*/
2 /*
3     Factorization code for BAIJ format.
4 */
5 #include "src/mat/impls/baij/seq/baij.h"
6 #include "src/inline/ilu.h"
7 
8 /* ------------------------------------------------------------*/
9 /*
10       Version for when blocks are 2 by 2
11 */
12 #undef __FUNCT__
13 #define __FUNCT__ "MatLUFactorNumeric_SeqBAIJ_2"
14 int MatLUFactorNumeric_SeqBAIJ_2(Mat A,Mat *B)
15 {
16   Mat                C = *B;
17   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
18   IS                 isrow = b->row,isicol = b->icol;
19   int                *r,*ic,ierr,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 int 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   int                ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
106   int                *ajtmpold,*ajtmp,nz,row;
107   int                *diag_offset = b->diag,*ai=a->i,*aj=a->j,*pj;
108   MatScalar          *pv,*v,*rtmp,*pc,*w,*x;
109   MatScalar          p1,p2,p3,p4,m1,m2,m3,m4,x1,x2,x3,x4;
110   MatScalar          *ba = b->a,*aa = a->a;
111 
112   PetscFunctionBegin;
113   ierr = PetscMalloc(4*(n+1)*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
114 
115   for (i=0; i<n; i++) {
116     nz    = bi[i+1] - bi[i];
117     ajtmp = bj + bi[i];
118     for  (j=0; j<nz; j++) {
119       x = rtmp+4*ajtmp[j];
120       x[0]  = x[1]  = x[2]  = x[3]  = 0.0;
121     }
122     /* load in initial (unfactored row) */
123     nz       = ai[i+1] - ai[i];
124     ajtmpold = aj + ai[i];
125     v        = aa + 4*ai[i];
126     for (j=0; j<nz; j++) {
127       x    = rtmp+4*ajtmpold[j];
128       x[0]  = v[0];  x[1]  = v[1];  x[2]  = v[2];  x[3]  = v[3];
129       v    += 4;
130     }
131     row = *ajtmp++;
132     while (row < i) {
133       pc  = rtmp + 4*row;
134       p1  = pc[0];  p2  = pc[1];  p3  = pc[2];  p4  = pc[3];
135       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0) {
136         pv = ba + 4*diag_offset[row];
137         pj = bj + diag_offset[row] + 1;
138         x1  = pv[0];  x2  = pv[1];  x3  = pv[2];  x4  = pv[3];
139         pc[0] = m1 = p1*x1 + p3*x2;
140         pc[1] = m2 = p2*x1 + p4*x2;
141         pc[2] = m3 = p1*x3 + p3*x4;
142         pc[3] = m4 = p2*x3 + p4*x4;
143         nz = bi[row+1] - diag_offset[row] - 1;
144         pv += 4;
145         for (j=0; j<nz; j++) {
146           x1   = pv[0];  x2  = pv[1];   x3 = pv[2];  x4  = pv[3];
147           x    = rtmp + 4*pj[j];
148           x[0] -= m1*x1 + m3*x2;
149           x[1] -= m2*x1 + m4*x2;
150           x[2] -= m1*x3 + m3*x4;
151           x[3] -= m2*x3 + m4*x4;
152           pv   += 4;
153         }
154         PetscLogFlops(16*nz+12);
155       }
156       row = *ajtmp++;
157     }
158     /* finished row so stick it into b->a */
159     pv = ba + 4*bi[i];
160     pj = bj + bi[i];
161     nz = bi[i+1] - bi[i];
162     for (j=0; j<nz; j++) {
163       x      = rtmp+4*pj[j];
164       pv[0]  = x[0];  pv[1]  = x[1];  pv[2]  = x[2];  pv[3]  = x[3];
165       pv   += 4;
166     }
167     /* invert diagonal block */
168     w = ba + 4*diag_offset[i];
169     ierr = Kernel_A_gets_inverse_A_2(w);CHKERRQ(ierr);
170     /*Kernel_A_gets_inverse_A(bs,w,v_pivots,v_work);*/
171   }
172 
173   ierr = PetscFree(rtmp);CHKERRQ(ierr);
174   C->factor    = FACTOR_LU;
175   C->assembled = PETSC_TRUE;
176   PetscLogFlops(1.3333*8*b->mbs); /* from inverting diagonal blocks */
177   PetscFunctionReturn(0);
178 }
179 
180 /* ----------------------------------------------------------- */
181 /*
182      Version for when blocks are 1 by 1.
183 */
184 #undef __FUNCT__
185 #define __FUNCT__ "MatLUFactorNumeric_SeqBAIJ_1"
186 int MatLUFactorNumeric_SeqBAIJ_1(Mat A,Mat *B)
187 {
188   Mat                C = *B;
189   Mat_SeqBAIJ        *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
190   IS                 isrow = b->row,isicol = b->icol;
191   int                *r,*ic,ierr,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
192   int                *ajtmpold,*ajtmp,nz,row,*ai = a->i,*aj = a->j;
193   int                *diag_offset = b->diag,diag,*pj;
194   MatScalar          *pv,*v,*rtmp,multiplier,*pc;
195   MatScalar          *ba = b->a,*aa = a->a;
196 
197   PetscFunctionBegin;
198   ierr  = ISGetIndices(isrow,&r);CHKERRQ(ierr);
199   ierr  = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
200   ierr  = PetscMalloc((n+1)*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
201 
202   for (i=0; i<n; i++) {
203     nz    = bi[i+1] - bi[i];
204     ajtmp = bj + bi[i];
205     for  (j=0; j<nz; j++) rtmp[ajtmp[j]] = 0.0;
206 
207     /* load in initial (unfactored row) */
208     nz       = ai[r[i]+1] - ai[r[i]];
209     ajtmpold = aj + ai[r[i]];
210     v        = aa + ai[r[i]];
211     for (j=0; j<nz; j++) rtmp[ic[ajtmpold[j]]] =  v[j];
212 
213     row = *ajtmp++;
214     while (row < i) {
215       pc = rtmp + row;
216       if (*pc != 0.0) {
217         pv         = ba + diag_offset[row];
218         pj         = bj + diag_offset[row] + 1;
219         multiplier = *pc * *pv++;
220         *pc        = multiplier;
221         nz         = bi[row+1] - diag_offset[row] - 1;
222         for (j=0; j<nz; j++) rtmp[pj[j]] -= multiplier * pv[j];
223         PetscLogFlops(1+2*nz);
224       }
225       row = *ajtmp++;
226     }
227     /* finished row so stick it into b->a */
228     pv = ba + bi[i];
229     pj = bj + bi[i];
230     nz = bi[i+1] - bi[i];
231     for (j=0; j<nz; j++) {pv[j] = rtmp[pj[j]];}
232     diag = diag_offset[i] - bi[i];
233     /* check pivot entry for current row */
234     if (pv[diag] == 0.0) {
235       SETERRQ(PETSC_ERR_MAT_LU_ZRPVT,"Zero pivot");
236     }
237     pv[diag] = 1.0/pv[diag];
238   }
239 
240   ierr = PetscFree(rtmp);CHKERRQ(ierr);
241   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
242   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
243   C->factor    = FACTOR_LU;
244   C->assembled = PETSC_TRUE;
245   PetscLogFlops(C->n);
246   PetscFunctionReturn(0);
247 }
248 
249 
250 /* ----------------------------------------------------------- */
251 #undef __FUNCT__
252 #define __FUNCT__ "MatLUFactor_SeqBAIJ"
253 int MatLUFactor_SeqBAIJ(Mat A,IS row,IS col,MatFactorInfo *info)
254 {
255   int         ierr;
256   Mat         C;
257 
258   PetscFunctionBegin;
259   ierr = MatLUFactorSymbolic(A,row,col,info,&C);CHKERRQ(ierr);
260   ierr = MatLUFactorNumeric(A,&C);CHKERRQ(ierr);
261   ierr = MatHeaderCopy(A,C);CHKERRQ(ierr);
262   PetscLogObjectParent(A,((Mat_SeqBAIJ*)(A->data))->icol);
263   PetscFunctionReturn(0);
264 }
265 
266 
267