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: PetscFunctionBegin;
16: PetscCall(VecGetArrayRead(bb, &b));
17: PetscCall(VecGetArray(xx, &x));
18: t = 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: ii = 0;
27: for (i = 0; i < n; i++) {
28: ic = 2 * c[i];
29: t[ii] = b[ic];
30: t[ii + 1] = b[ic + 1];
31: ii += 2;
32: }
34: /* forward solve the U^T */
35: idx = 0;
36: for (i = 0; i < n; i++) {
37: v = aa + 4 * diag[i];
38: /* multiply by the inverse of the block diagonal */
39: x1 = t[idx];
40: x2 = t[1 + idx];
41: s1 = v[0] * x1 + v[1] * x2;
42: s2 = v[2] * x1 + v[3] * x2;
43: v += 4;
45: vi = aj + diag[i] + 1;
46: nz = ai[i + 1] - diag[i] - 1;
47: while (nz--) {
48: oidx = 2 * (*vi++);
49: t[oidx] -= v[0] * s1 + v[1] * s2;
50: t[oidx + 1] -= v[2] * s1 + v[3] * s2;
51: v += 4;
52: }
53: t[idx] = s1;
54: t[1 + idx] = s2;
55: idx += 2;
56: }
57: /* backward solve the L^T */
58: for (i = n - 1; i >= 0; i--) {
59: v = aa + 4 * diag[i] - 4;
60: vi = aj + diag[i] - 1;
61: nz = diag[i] - ai[i];
62: idt = 2 * i;
63: s1 = t[idt];
64: s2 = t[1 + idt];
65: while (nz--) {
66: idx = 2 * (*vi--);
67: t[idx] -= v[0] * s1 + v[1] * s2;
68: t[idx + 1] -= v[2] * s1 + v[3] * s2;
69: v -= 4;
70: }
71: }
73: /* copy t into x according to permutation */
74: ii = 0;
75: for (i = 0; i < n; i++) {
76: ir = 2 * r[i];
77: x[ir] = t[ii];
78: x[ir + 1] = t[ii + 1];
79: ii += 2;
80: }
82: PetscCall(ISRestoreIndices(isrow, &rout));
83: PetscCall(ISRestoreIndices(iscol, &cout));
84: PetscCall(VecRestoreArrayRead(bb, &b));
85: PetscCall(VecRestoreArray(xx, &x));
86: PetscCall(PetscLogFlops(2.0 * 4 * (a->nz) - 2.0 * A->cmap->n));
87: PetscFunctionReturn(PETSC_SUCCESS);
88: }
90: PetscErrorCode MatSolveTranspose_SeqBAIJ_2(Mat A, Vec bb, Vec xx)
91: {
92: Mat_SeqBAIJ *a = (Mat_SeqBAIJ *)A->data;
93: IS iscol = a->col, isrow = a->row;
94: const PetscInt n = a->mbs, *vi, *ai = a->i, *aj = a->j, *diag = a->diag;
95: const PetscInt *r, *c, *rout, *cout;
96: PetscInt nz, idx, idt, j, i, oidx, ii, ic, ir;
97: const PetscInt bs = A->rmap->bs, bs2 = a->bs2;
98: const MatScalar *aa = a->a, *v;
99: PetscScalar s1, s2, x1, x2, *x, *t;
100: const PetscScalar *b;
102: PetscFunctionBegin;
103: PetscCall(VecGetArrayRead(bb, &b));
104: PetscCall(VecGetArray(xx, &x));
105: t = a->solve_work;
107: PetscCall(ISGetIndices(isrow, &rout));
108: r = rout;
109: PetscCall(ISGetIndices(iscol, &cout));
110: c = cout;
112: /* copy b into temp work space according to permutation */
113: for (i = 0; i < n; i++) {
114: ii = bs * i;
115: ic = bs * c[i];
116: t[ii] = b[ic];
117: t[ii + 1] = b[ic + 1];
118: }
120: /* forward solve the U^T */
121: idx = 0;
122: for (i = 0; i < n; i++) {
123: v = aa + bs2 * diag[i];
124: /* multiply by the inverse of the block diagonal */
125: x1 = t[idx];
126: x2 = t[1 + idx];
127: s1 = v[0] * x1 + v[1] * x2;
128: s2 = v[2] * x1 + v[3] * x2;
129: v -= bs2;
131: vi = aj + diag[i] - 1;
132: nz = diag[i] - diag[i + 1] - 1;
133: for (j = 0; j > -nz; j--) {
134: oidx = bs * vi[j];
135: t[oidx] -= v[0] * s1 + v[1] * s2;
136: t[oidx + 1] -= v[2] * s1 + v[3] * s2;
137: v -= bs2;
138: }
139: t[idx] = s1;
140: t[1 + idx] = s2;
141: idx += bs;
142: }
143: /* backward solve the L^T */
144: for (i = n - 1; i >= 0; i--) {
145: v = aa + bs2 * ai[i];
146: vi = aj + ai[i];
147: nz = ai[i + 1] - ai[i];
148: idt = bs * i;
149: s1 = t[idt];
150: s2 = t[1 + idt];
151: for (j = 0; j < nz; j++) {
152: idx = bs * vi[j];
153: t[idx] -= v[0] * s1 + v[1] * s2;
154: t[idx + 1] -= v[2] * s1 + v[3] * s2;
155: v += bs2;
156: }
157: }
159: /* copy t into x according to permutation */
160: for (i = 0; i < n; i++) {
161: ii = bs * i;
162: ir = bs * r[i];
163: x[ir] = t[ii];
164: x[ir + 1] = t[ii + 1];
165: }
167: PetscCall(ISRestoreIndices(isrow, &rout));
168: PetscCall(ISRestoreIndices(iscol, &cout));
169: PetscCall(VecRestoreArrayRead(bb, &b));
170: PetscCall(VecRestoreArray(xx, &x));
171: PetscCall(PetscLogFlops(2.0 * bs2 * (a->nz) - bs * A->cmap->n));
172: PetscFunctionReturn(PETSC_SUCCESS);
173: }