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