1 #include <../src/mat/impls/baij/seq/baij.h>
2 #include <petsc/private/kernels/blockinvert.h>
3
MatSolveTranspose_SeqBAIJ_2_inplace(Mat A,Vec bb,Vec xx)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;
14
15 PetscFunctionBegin;
16 PetscCall(VecGetArrayRead(bb, &b));
17 PetscCall(VecGetArray(xx, &x));
18 t = a->solve_work;
19
20 PetscCall(ISGetIndices(isrow, &rout));
21 r = rout;
22 PetscCall(ISGetIndices(iscol, &cout));
23 c = cout;
24
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 }
33
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;
44
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 }
72
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 }
81
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 }
89
MatSolveTranspose_SeqBAIJ_2(Mat A,Vec bb,Vec xx)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;
101
102 PetscFunctionBegin;
103 PetscCall(VecGetArrayRead(bb, &b));
104 PetscCall(VecGetArray(xx, &x));
105 t = a->solve_work;
106
107 PetscCall(ISGetIndices(isrow, &rout));
108 r = rout;
109 PetscCall(ISGetIndices(iscol, &cout));
110 c = cout;
111
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 }
119
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;
130
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 }
158
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 }
166
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 }
174