Actual source code: baijsolvtran2.c
1: #include <../src/mat/impls/baij/seq/baij.h>
2: #include <petsc/private/kernels/blockinvert.h>
4: PetscErrorCode MatSolveTranspose_SeqBAIJ_2_inplace(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 *r, *c, *rout, *cout;
9: const PetscInt *diag = a->diag, n = a->mbs, *vi, *ai = a->i, *aj = a->j;
10: PetscInt i, nz, idx, idt, ii, ic, ir, oidx;
11: const MatScalar *aa = a->a, *v;
12: PetscScalar s1, s2, x1, x2, *x, *t;
13: const PetscScalar *b;
15: VecGetArrayRead(bb, &b);
16: VecGetArray(xx, &x);
17: t = a->solve_work;
19: ISGetIndices(isrow, &rout);
20: r = rout;
21: ISGetIndices(iscol, &cout);
22: c = cout;
24: /* copy the b into temp work space according to permutation */
25: ii = 0;
26: for (i = 0; i < n; i++) {
27: ic = 2 * c[i];
28: t[ii] = b[ic];
29: t[ii + 1] = b[ic + 1];
30: ii += 2;
31: }
33: /* forward solve the U^T */
34: idx = 0;
35: for (i = 0; i < n; i++) {
36: v = aa + 4 * diag[i];
37: /* multiply by the inverse of the block diagonal */
38: x1 = t[idx];
39: x2 = t[1 + idx];
40: s1 = v[0] * x1 + v[1] * x2;
41: s2 = v[2] * x1 + v[3] * x2;
42: v += 4;
44: vi = aj + diag[i] + 1;
45: nz = ai[i + 1] - diag[i] - 1;
46: while (nz--) {
47: oidx = 2 * (*vi++);
48: t[oidx] -= v[0] * s1 + v[1] * s2;
49: t[oidx + 1] -= v[2] * s1 + v[3] * s2;
50: v += 4;
51: }
52: t[idx] = s1;
53: t[1 + idx] = s2;
54: idx += 2;
55: }
56: /* backward solve the L^T */
57: for (i = n - 1; i >= 0; i--) {
58: v = aa + 4 * diag[i] - 4;
59: vi = aj + diag[i] - 1;
60: nz = diag[i] - ai[i];
61: idt = 2 * i;
62: s1 = t[idt];
63: s2 = t[1 + idt];
64: while (nz--) {
65: idx = 2 * (*vi--);
66: t[idx] -= v[0] * s1 + v[1] * s2;
67: t[idx + 1] -= v[2] * s1 + v[3] * s2;
68: v -= 4;
69: }
70: }
72: /* copy t into x according to permutation */
73: ii = 0;
74: for (i = 0; i < n; i++) {
75: ir = 2 * r[i];
76: x[ir] = t[ii];
77: x[ir + 1] = t[ii + 1];
78: ii += 2;
79: }
81: ISRestoreIndices(isrow, &rout);
82: ISRestoreIndices(iscol, &cout);
83: VecRestoreArrayRead(bb, &b);
84: VecRestoreArray(xx, &x);
85: PetscLogFlops(2.0 * 4 * (a->nz) - 2.0 * A->cmap->n);
86: return 0;
87: }
89: PetscErrorCode MatSolveTranspose_SeqBAIJ_2(Mat A, Vec bb, Vec xx)
90: {
91: Mat_SeqBAIJ *a = (Mat_SeqBAIJ *)A->data;
92: IS iscol = a->col, isrow = a->row;
93: const PetscInt n = a->mbs, *vi, *ai = a->i, *aj = a->j, *diag = a->diag;
94: const PetscInt *r, *c, *rout, *cout;
95: PetscInt nz, idx, idt, j, i, oidx, ii, ic, ir;
96: const PetscInt bs = A->rmap->bs, bs2 = a->bs2;
97: const MatScalar *aa = a->a, *v;
98: PetscScalar s1, s2, x1, x2, *x, *t;
99: const PetscScalar *b;
101: VecGetArrayRead(bb, &b);
102: VecGetArray(xx, &x);
103: t = a->solve_work;
105: ISGetIndices(isrow, &rout);
106: r = rout;
107: ISGetIndices(iscol, &cout);
108: c = cout;
110: /* copy b into temp work space according to permutation */
111: for (i = 0; i < n; i++) {
112: ii = bs * i;
113: ic = bs * c[i];
114: t[ii] = b[ic];
115: t[ii + 1] = b[ic + 1];
116: }
118: /* forward solve the U^T */
119: idx = 0;
120: for (i = 0; i < n; i++) {
121: v = aa + bs2 * diag[i];
122: /* multiply by the inverse of the block diagonal */
123: x1 = t[idx];
124: x2 = t[1 + idx];
125: s1 = v[0] * x1 + v[1] * x2;
126: s2 = v[2] * x1 + v[3] * x2;
127: v -= bs2;
129: vi = aj + diag[i] - 1;
130: nz = diag[i] - diag[i + 1] - 1;
131: for (j = 0; j > -nz; j--) {
132: oidx = bs * vi[j];
133: t[oidx] -= v[0] * s1 + v[1] * s2;
134: t[oidx + 1] -= v[2] * s1 + v[3] * s2;
135: v -= bs2;
136: }
137: t[idx] = s1;
138: t[1 + idx] = s2;
139: idx += bs;
140: }
141: /* backward solve the L^T */
142: for (i = n - 1; i >= 0; i--) {
143: v = aa + bs2 * ai[i];
144: vi = aj + ai[i];
145: nz = ai[i + 1] - ai[i];
146: idt = bs * i;
147: s1 = t[idt];
148: s2 = t[1 + idt];
149: for (j = 0; j < nz; j++) {
150: idx = bs * vi[j];
151: t[idx] -= v[0] * s1 + v[1] * s2;
152: t[idx + 1] -= v[2] * s1 + v[3] * s2;
153: v += bs2;
154: }
155: }
157: /* copy t into x according to permutation */
158: for (i = 0; i < n; i++) {
159: ii = bs * i;
160: ir = bs * r[i];
161: x[ir] = t[ii];
162: x[ir + 1] = t[ii + 1];
163: }
165: ISRestoreIndices(isrow, &rout);
166: ISRestoreIndices(iscol, &cout);
167: VecRestoreArrayRead(bb, &b);
168: VecRestoreArray(xx, &x);
169: PetscLogFlops(2.0 * bs2 * (a->nz) - bs * A->cmap->n);
170: return 0;
171: }