Actual source code: baijsolvtran1.c
1: #include <../src/mat/impls/baij/seq/baij.h>
2: #include <petsc/private/kernels/blockinvert.h>
4: PetscErrorCode MatSolveTranspose_SeqBAIJ_1(Mat A, Vec bb, Vec xx)
5: {
6: Mat_SeqBAIJ *a = (Mat_SeqBAIJ *)A->data;
7: IS iscol = a->col, isrow = a->row;
8: const PetscInt *rout, *cout, *r, *c, *adiag = a->diag, *ai = a->i, *aj = a->j, *vi;
9: PetscInt i, n = a->mbs, j;
10: PetscInt nz;
11: PetscScalar *x, *tmp, s1;
12: const MatScalar *aa = a->a, *v;
13: const PetscScalar *b;
15: PetscFunctionBegin;
16: PetscCall(VecGetArrayRead(bb, &b));
17: PetscCall(VecGetArray(xx, &x));
18: tmp = a->solve_work;
20: PetscCall(ISGetIndices(isrow, &rout));
21: r = rout;
22: PetscCall(ISGetIndices(iscol, &cout));
23: c = cout;
25: /* copy the b into temp work space according to permutation */
26: for (i = 0; i < n; i++) tmp[i] = b[c[i]];
28: /* forward solve the U^T */
29: for (i = 0; i < n; i++) {
30: v = aa + adiag[i + 1] + 1;
31: vi = aj + adiag[i + 1] + 1;
32: nz = adiag[i] - adiag[i + 1] - 1;
33: s1 = tmp[i];
34: s1 *= v[nz]; /* multiply by inverse of diagonal entry */
35: for (j = 0; j < nz; j++) tmp[vi[j]] -= s1 * v[j];
36: tmp[i] = s1;
37: }
39: /* backward solve the L^T */
40: for (i = n - 1; i >= 0; i--) {
41: v = aa + ai[i];
42: vi = aj + ai[i];
43: nz = ai[i + 1] - ai[i];
44: s1 = tmp[i];
45: for (j = 0; j < nz; j++) tmp[vi[j]] -= s1 * v[j];
46: }
48: /* copy tmp into x according to permutation */
49: for (i = 0; i < n; i++) x[r[i]] = tmp[i];
51: PetscCall(ISRestoreIndices(isrow, &rout));
52: PetscCall(ISRestoreIndices(iscol, &cout));
53: PetscCall(VecRestoreArrayRead(bb, &b));
54: PetscCall(VecRestoreArray(xx, &x));
56: PetscCall(PetscLogFlops(2.0 * a->nz - A->cmap->n));
57: PetscFunctionReturn(PETSC_SUCCESS);
58: }
60: PetscErrorCode MatSolveTranspose_SeqBAIJ_1_inplace(Mat A, Vec bb, Vec xx)
61: {
62: Mat_SeqBAIJ *a = (Mat_SeqBAIJ *)A->data;
63: IS iscol = a->col, isrow = a->row;
64: const PetscInt *r, *c, *rout, *cout;
65: const PetscInt *diag = a->diag, n = a->mbs, *vi, *ai = a->i, *aj = a->j;
66: PetscInt i, nz;
67: const MatScalar *aa = a->a, *v;
68: PetscScalar s1, *x, *t;
69: const PetscScalar *b;
71: PetscFunctionBegin;
72: PetscCall(VecGetArrayRead(bb, &b));
73: PetscCall(VecGetArray(xx, &x));
74: t = a->solve_work;
76: PetscCall(ISGetIndices(isrow, &rout));
77: r = rout;
78: PetscCall(ISGetIndices(iscol, &cout));
79: c = cout;
81: /* copy the b into temp work space according to permutation */
82: for (i = 0; i < n; i++) t[i] = b[c[i]];
84: /* forward solve the U^T */
85: for (i = 0; i < n; i++) {
86: v = aa + diag[i];
87: /* multiply by the inverse of the block diagonal */
88: s1 = (*v++) * t[i];
89: vi = aj + diag[i] + 1;
90: nz = ai[i + 1] - diag[i] - 1;
91: while (nz--) t[*vi++] -= (*v++) * s1;
92: t[i] = s1;
93: }
94: /* backward solve the L^T */
95: for (i = n - 1; i >= 0; i--) {
96: v = aa + diag[i] - 1;
97: vi = aj + diag[i] - 1;
98: nz = diag[i] - ai[i];
99: s1 = t[i];
100: while (nz--) t[*vi--] -= (*v--) * s1;
101: }
103: /* copy t into x according to permutation */
104: for (i = 0; i < n; i++) x[r[i]] = t[i];
106: PetscCall(ISRestoreIndices(isrow, &rout));
107: PetscCall(ISRestoreIndices(iscol, &cout));
108: PetscCall(VecRestoreArrayRead(bb, &b));
109: PetscCall(VecRestoreArray(xx, &x));
110: PetscCall(PetscLogFlops(2.0 * (a->nz) - A->cmap->n));
111: PetscFunctionReturn(PETSC_SUCCESS);
112: }