xref: /petsc/src/mat/impls/baij/seq/baijfact13.c (revision 2a6744eb01855f5aa328eb8fdf4b0d01e72ad151)
1 #define PETSCMAT_DLL
2 
3 /*
4     Factorization code for BAIJ format.
5 */
6 #include "src/mat/impls/baij/seq/baij.h"
7 #include "src/inline/ilu.h"
8 
9 /* ------------------------------------------------------------*/
10 /*
11       Version for when blocks are 3 by 3
12 */
13 #undef __FUNCT__
14 #define __FUNCT__ "MatLUFactorNumeric_SeqBAIJ_3"
15 PetscErrorCode MatLUFactorNumeric_SeqBAIJ_3(Mat A,MatFactorInfo *info,Mat *B)
16 {
17   Mat            C = *B;
18   Mat_SeqBAIJ    *a = (Mat_SeqBAIJ*)A->data,*b = (Mat_SeqBAIJ *)C->data;
19   IS             isrow = b->row,isicol = b->icol;
20   PetscErrorCode ierr;
21   PetscInt       *r,*ic,i,j,n = a->mbs,*bi = b->i,*bj = b->j;
22   PetscInt       *ajtmpold,*ajtmp,nz,row,*ai=a->i,*aj=a->j;
23   PetscInt       *diag_offset = b->diag,idx,*pj;
24   MatScalar      *pv,*v,*rtmp,*pc,*w,*x;
25   MatScalar      p1,p2,p3,p4,m1,m2,m3,m4,m5,m6,m7,m8,m9,x1,x2,x3,x4;
26   MatScalar      p5,p6,p7,p8,p9,x5,x6,x7,x8,x9;
27   MatScalar      *ba = b->a,*aa = a->a;
28 
29   PetscFunctionBegin;
30   ierr = ISGetIndices(isrow,&r);CHKERRQ(ierr);
31   ierr = ISGetIndices(isicol,&ic);CHKERRQ(ierr);
32   ierr = PetscMalloc(9*(n+1)*sizeof(MatScalar),&rtmp);CHKERRQ(ierr);
33 
34   for (i=0; i<n; i++) {
35     nz    = bi[i+1] - bi[i];
36     ajtmp = bj + bi[i];
37     for  (j=0; j<nz; j++) {
38       x = rtmp + 9*ajtmp[j];
39       x[0] = x[1] = x[2] = x[3] = x[4] = x[5] = x[6] = x[7] = x[8] = 0.0;
40     }
41     /* load in initial (unfactored row) */
42     idx      = r[i];
43     nz       = ai[idx+1] - ai[idx];
44     ajtmpold = aj + ai[idx];
45     v        = aa + 9*ai[idx];
46     for (j=0; j<nz; j++) {
47       x    = rtmp + 9*ic[ajtmpold[j]];
48       x[0] = v[0]; x[1] = v[1]; x[2] = v[2]; x[3] = v[3];
49       x[4] = v[4]; x[5] = v[5]; x[6] = v[6]; x[7] = v[7]; x[8] = v[8];
50       v    += 9;
51     }
52     row = *ajtmp++;
53     while (row < i) {
54       pc = rtmp + 9*row;
55       p1 = pc[0]; p2 = pc[1]; p3 = pc[2]; p4 = pc[3];
56       p5 = pc[4]; p6 = pc[5]; p7 = pc[6]; p8 = pc[7]; p9 = pc[8];
57       if (p1 != 0.0 || p2 != 0.0 || p3 != 0.0 || p4 != 0.0 || p5 != 0.0 ||
58           p6 != 0.0 || p7 != 0.0 || p8 != 0.0 || p9 != 0.0) {
59         pv = ba + 9*diag_offset[row];
60         pj = bj + diag_offset[row] + 1;
61         x1 = pv[0]; x2 = pv[1]; x3 = pv[2]; x4 = pv[3];
62         x5 = pv[4]; x6 = pv[5]; x7 = pv[6]; x8 = pv[7]; x9 = pv[8];
63         pc[0] = m1 = p1*x1 + p4*x2 + p7*x3;
64         pc[1] = m2 = p2*x1 + p5*x2 + p8*x3;
65         pc[2] = m3 = p3*x1 + p6*x2 + p9*x3;
66 
67         pc[3] = m4 = p1*x4 + p4*x5 + p7*x6;
68         pc[4] = m5 = p2*x4 + p5*x5 + p8*x6;
69         pc[5] = m6 = p3*x4 + p6*x5 + p9*x6;
70 
71         pc[6] = m7 = p1*x7 + p4*x8 + p7*x9;
72         pc[7] = m8 = p2*x7 + p5*x8 + p8*x9;
73         pc[8] = m9 = p3*x7 + p6*x8 + p9*x9;
74         nz = bi[row+1] - diag_offset[row] - 1;
75         pv += 9;
76         for (j=0; j<nz; j++) {
77           x1   = pv[0]; x2 = pv[1]; x3 = pv[2]; x4 = pv[3];
78           x5   = pv[4]; x6 = pv[5]; x7 = pv[6]; x8 = pv[7]; x9 = pv[8];
79           x    = rtmp + 9*pj[j];
80           x[0] -= m1*x1 + m4*x2 + m7*x3;
81           x[1] -= m2*x1 + m5*x2 + m8*x3;
82           x[2] -= m3*x1 + m6*x2 + m9*x3;
83 
84           x[3] -= m1*x4 + m4*x5 + m7*x6;
85           x[4] -= m2*x4 + m5*x5 + m8*x6;
86           x[5] -= m3*x4 + m6*x5 + m9*x6;
87 
88           x[6] -= m1*x7 + m4*x8 + m7*x9;
89           x[7] -= m2*x7 + m5*x8 + m8*x9;
90           x[8] -= m3*x7 + m6*x8 + m9*x9;
91           pv   += 9;
92         }
93         ierr = PetscLogFlops(54*nz+36);CHKERRQ(ierr);
94       }
95       row = *ajtmp++;
96     }
97     /* finished row so stick it into b->a */
98     pv = ba + 9*bi[i];
99     pj = bj + bi[i];
100     nz = bi[i+1] - bi[i];
101     for (j=0; j<nz; j++) {
102       x     = rtmp + 9*pj[j];
103       pv[0] = x[0]; pv[1] = x[1]; pv[2] = x[2]; pv[3] = x[3];
104       pv[4] = x[4]; pv[5] = x[5]; pv[6] = x[6]; pv[7] = x[7]; pv[8] = x[8];
105       pv   += 9;
106     }
107     /* invert diagonal block */
108     w = ba + 9*diag_offset[i];
109     ierr = Kernel_A_gets_inverse_A_3(w);CHKERRQ(ierr);
110   }
111 
112   ierr = PetscFree(rtmp);CHKERRQ(ierr);
113   ierr = ISRestoreIndices(isicol,&ic);CHKERRQ(ierr);
114   ierr = ISRestoreIndices(isrow,&r);CHKERRQ(ierr);
115   C->factor = FACTOR_LU;
116   C->assembled = PETSC_TRUE;
117   ierr = PetscLogFlops(1.3333*27*b->mbs);CHKERRQ(ierr); /* from inverting diagonal blocks */
118   PetscFunctionReturn(0);
119 }
120