Actual source code: baijsolvtrannat3.c
petsc-3.12.5 2020-03-29
1: #include <../src/mat/impls/baij/seq/baij.h>
3: PetscErrorCode MatSolveTranspose_SeqBAIJ_3_NaturalOrdering_inplace(Mat A,Vec bb,Vec xx)
4: {
5: Mat_SeqBAIJ *a=(Mat_SeqBAIJ*)A->data;
6: PetscErrorCode ierr;
7: const PetscInt n=a->mbs,*vi,*ai=a->i,*aj=a->j,*diag=a->diag;
8: PetscInt i,nz,idx,idt,oidx;
9: const MatScalar *aa=a->a,*v;
10: PetscScalar s1,s2,s3,x1,x2,x3,*x;
13: VecCopy(bb,xx);
14: VecGetArray(xx,&x);
16: /* forward solve the U^T */
17: idx = 0;
18: for (i=0; i<n; i++) {
20: v = aa + 9*diag[i];
21: /* multiply by the inverse of the block diagonal */
22: x1 = x[idx]; x2 = x[1+idx]; x3 = x[2+idx];
23: s1 = v[0]*x1 + v[1]*x2 + v[2]*x3;
24: s2 = v[3]*x1 + v[4]*x2 + v[5]*x3;
25: s3 = v[6]*x1 + v[7]*x2 + v[8]*x3;
26: v += 9;
28: vi = aj + diag[i] + 1;
29: nz = ai[i+1] - diag[i] - 1;
30: while (nz--) {
31: oidx = 3*(*vi++);
32: x[oidx] -= v[0]*s1 + v[1]*s2 + v[2]*s3;
33: x[oidx+1] -= v[3]*s1 + v[4]*s2 + v[5]*s3;
34: x[oidx+2] -= v[6]*s1 + v[7]*s2 + v[8]*s3;
35: v += 9;
36: }
37: x[idx] = s1;x[1+idx] = s2; x[2+idx] = s3;
38: idx += 3;
39: }
40: /* backward solve the L^T */
41: for (i=n-1; i>=0; i--) {
42: v = aa + 9*diag[i] - 9;
43: vi = aj + diag[i] - 1;
44: nz = diag[i] - ai[i];
45: idt = 3*i;
46: s1 = x[idt]; s2 = x[1+idt]; s3 = x[2+idt];
47: while (nz--) {
48: idx = 3*(*vi--);
49: x[idx] -= v[0]*s1 + v[1]*s2 + v[2]*s3;
50: x[idx+1] -= v[3]*s1 + v[4]*s2 + v[5]*s3;
51: x[idx+2] -= v[6]*s1 + v[7]*s2 + v[8]*s3;
52: v -= 9;
53: }
54: }
55: VecRestoreArray(xx,&x);
56: PetscLogFlops(2.0*9.0*(a->nz) - 3.0*A->cmap->n);
57: return(0);
58: }
60: PetscErrorCode MatSolveTranspose_SeqBAIJ_3_NaturalOrdering(Mat A,Vec bb,Vec xx)
61: {
62: Mat_SeqBAIJ *a=(Mat_SeqBAIJ*)A->data;
63: PetscErrorCode ierr;
64: const PetscInt n=a->mbs,*vi,*ai=a->i,*aj=a->j,*diag=a->diag;
65: PetscInt nz,idx,idt,j,i,oidx;
66: const PetscInt bs =A->rmap->bs,bs2=a->bs2;
67: const MatScalar *aa=a->a,*v;
68: PetscScalar s1,s2,s3,x1,x2,x3,*x;
71: VecCopy(bb,xx);
72: VecGetArray(xx,&x);
74: /* forward solve the U^T */
75: idx = 0;
76: for (i=0; i<n; i++) {
77: v = aa + bs2*diag[i];
78: /* multiply by the inverse of the block diagonal */
79: x1 = x[idx]; x2 = x[1+idx]; x3 = x[2+idx];
80: s1 = v[0]*x1 + v[1]*x2 + v[2]*x3;
81: s2 = v[3]*x1 + v[4]*x2 + v[5]*x3;
82: s3 = v[6]*x1 + v[7]*x2 + v[8]*x3;
83: v -= bs2;
85: vi = aj + diag[i] - 1;
86: nz = diag[i] - diag[i+1] - 1;
87: for (j=0; j>-nz; j--) {
88: oidx = bs*vi[j];
89: x[oidx] -= v[0]*s1 + v[1]*s2 + v[2]*s3;
90: x[oidx+1] -= v[3]*s1 + v[4]*s2 + v[5]*s3;
91: x[oidx+2] -= v[6]*s1 + v[7]*s2 + v[8]*s3;
92: v -= bs2;
93: }
94: x[idx] = s1;x[1+idx] = s2; x[2+idx] = s3;
95: idx += bs;
96: }
97: /* backward solve the L^T */
98: for (i=n-1; i>=0; i--) {
99: v = aa + bs2*ai[i];
100: vi = aj + ai[i];
101: nz = ai[i+1] - ai[i];
102: idt = bs*i;
103: s1 = x[idt]; s2 = x[1+idt]; s3 = x[2+idt];
104: for (j=0; j<nz; j++) {
105: idx = bs*vi[j];
106: x[idx] -= v[0]*s1 + v[1]*s2 + v[2]*s3;
107: x[idx+1] -= v[3]*s1 + v[4]*s2 + v[5]*s3;
108: x[idx+2] -= v[6]*s1 + v[7]*s2 + v[8]*s3;
109: v += bs2;
110: }
111: }
112: VecRestoreArray(xx,&x);
113: PetscLogFlops(2.0*bs2*(a->nz) - bs*A->cmap->n);
114: return(0);
115: }