xref: /petsc/src/mat/impls/baij/seq/baijsolvtrannat6.c (revision 31d78bcd2b98084dc1368b20eb1129c8b9fb39fe)
1 #include <../src/mat/impls/baij/seq/baij.h>
2 
MatSolveTranspose_SeqBAIJ_6_NaturalOrdering_inplace(Mat A,Vec bb,Vec xx)3 PetscErrorCode MatSolveTranspose_SeqBAIJ_6_NaturalOrdering_inplace(Mat A, Vec bb, Vec xx)
4 {
5   Mat_SeqBAIJ     *a    = (Mat_SeqBAIJ *)A->data;
6   const PetscInt  *diag = a->diag, n = a->mbs, *vi, *ai = a->i, *aj = a->j;
7   PetscInt         i, nz, idx, idt, oidx;
8   const MatScalar *aa = a->a, *v;
9   PetscScalar      s1, s2, s3, s4, s5, s6, x1, x2, x3, x4, x5, x6, *x;
10 
11   PetscFunctionBegin;
12   PetscCall(VecCopy(bb, xx));
13   PetscCall(VecGetArray(xx, &x));
14 
15   /* forward solve the U^T */
16   idx = 0;
17   for (i = 0; i < n; i++) {
18     v = aa + 36 * diag[i];
19     /* multiply by the inverse of the block diagonal */
20     x1 = x[idx];
21     x2 = x[1 + idx];
22     x3 = x[2 + idx];
23     x4 = x[3 + idx];
24     x5 = x[4 + idx];
25     x6 = x[5 + idx];
26     s1 = v[0] * x1 + v[1] * x2 + v[2] * x3 + v[3] * x4 + v[4] * x5 + v[5] * x6;
27     s2 = v[6] * x1 + v[7] * x2 + v[8] * x3 + v[9] * x4 + v[10] * x5 + v[11] * x6;
28     s3 = v[12] * x1 + v[13] * x2 + v[14] * x3 + v[15] * x4 + v[16] * x5 + v[17] * x6;
29     s4 = v[18] * x1 + v[19] * x2 + v[20] * x3 + v[21] * x4 + v[22] * x5 + v[23] * x6;
30     s5 = v[24] * x1 + v[25] * x2 + v[26] * x3 + v[27] * x4 + v[28] * x5 + v[29] * x6;
31     s6 = v[30] * x1 + v[31] * x2 + v[32] * x3 + v[33] * x4 + v[34] * x5 + v[35] * x6;
32     v += 36;
33 
34     vi = aj + diag[i] + 1;
35     nz = ai[i + 1] - diag[i] - 1;
36     while (nz--) {
37       oidx = 6 * (*vi++);
38       x[oidx] -= v[0] * s1 + v[1] * s2 + v[2] * s3 + v[3] * s4 + v[4] * s5 + v[5] * s6;
39       x[oidx + 1] -= v[6] * s1 + v[7] * s2 + v[8] * s3 + v[9] * s4 + v[10] * s5 + v[11] * s6;
40       x[oidx + 2] -= v[12] * s1 + v[13] * s2 + v[14] * s3 + v[15] * s4 + v[16] * s5 + v[17] * s6;
41       x[oidx + 3] -= v[18] * s1 + v[19] * s2 + v[20] * s3 + v[21] * s4 + v[22] * s5 + v[23] * s6;
42       x[oidx + 4] -= v[24] * s1 + v[25] * s2 + v[26] * s3 + v[27] * s4 + v[28] * s5 + v[29] * s6;
43       x[oidx + 5] -= v[30] * s1 + v[31] * s2 + v[32] * s3 + v[33] * s4 + v[34] * s5 + v[35] * s6;
44       v += 36;
45     }
46     x[idx]     = s1;
47     x[1 + idx] = s2;
48     x[2 + idx] = s3;
49     x[3 + idx] = s4;
50     x[4 + idx] = s5;
51     x[5 + idx] = s6;
52     idx += 6;
53   }
54   /* backward solve the L^T */
55   for (i = n - 1; i >= 0; i--) {
56     v   = aa + 36 * diag[i] - 36;
57     vi  = aj + diag[i] - 1;
58     nz  = diag[i] - ai[i];
59     idt = 6 * i;
60     s1  = x[idt];
61     s2  = x[1 + idt];
62     s3  = x[2 + idt];
63     s4  = x[3 + idt];
64     s5  = x[4 + idt];
65     s6  = x[5 + idt];
66     while (nz--) {
67       idx = 6 * (*vi--);
68       x[idx] -= v[0] * s1 + v[1] * s2 + v[2] * s3 + v[3] * s4 + v[4] * s5 + v[5] * s6;
69       x[idx + 1] -= v[6] * s1 + v[7] * s2 + v[8] * s3 + v[9] * s4 + v[10] * s5 + v[11] * s6;
70       x[idx + 2] -= v[12] * s1 + v[13] * s2 + v[14] * s3 + v[15] * s4 + v[16] * s5 + v[17] * s6;
71       x[idx + 3] -= v[18] * s1 + v[19] * s2 + v[20] * s3 + v[21] * s4 + v[22] * s5 + v[23] * s6;
72       x[idx + 4] -= v[24] * s1 + v[25] * s2 + v[26] * s3 + v[27] * s4 + v[28] * s5 + v[29] * s6;
73       x[idx + 5] -= v[30] * s1 + v[31] * s2 + v[32] * s3 + v[33] * s4 + v[34] * s5 + v[35] * s6;
74       v -= 36;
75     }
76   }
77   PetscCall(VecRestoreArray(xx, &x));
78   PetscCall(PetscLogFlops(2.0 * 36 * (a->nz) - 6.0 * A->cmap->n));
79   PetscFunctionReturn(PETSC_SUCCESS);
80 }
81 
MatSolveTranspose_SeqBAIJ_6_NaturalOrdering(Mat A,Vec bb,Vec xx)82 PetscErrorCode MatSolveTranspose_SeqBAIJ_6_NaturalOrdering(Mat A, Vec bb, Vec xx)
83 {
84   Mat_SeqBAIJ     *a = (Mat_SeqBAIJ *)A->data;
85   const PetscInt   n = a->mbs, *vi, *ai = a->i, *aj = a->j, *diag = a->diag;
86   PetscInt         nz, idx, idt, j, i, oidx;
87   const PetscInt   bs = A->rmap->bs, bs2 = a->bs2;
88   const MatScalar *aa = a->a, *v;
89   PetscScalar      s1, s2, s3, s4, s5, s6, x1, x2, x3, x4, x5, x6, *x;
90 
91   PetscFunctionBegin;
92   PetscCall(VecCopy(bb, xx));
93   PetscCall(VecGetArray(xx, &x));
94 
95   /* forward solve the U^T */
96   idx = 0;
97   for (i = 0; i < n; i++) {
98     v = aa + bs2 * diag[i];
99     /* multiply by the inverse of the block diagonal */
100     x1 = x[idx];
101     x2 = x[1 + idx];
102     x3 = x[2 + idx];
103     x4 = x[3 + idx];
104     x5 = x[4 + idx];
105     x6 = x[5 + idx];
106     s1 = v[0] * x1 + v[1] * x2 + v[2] * x3 + v[3] * x4 + v[4] * x5 + v[5] * x6;
107     s2 = v[6] * x1 + v[7] * x2 + v[8] * x3 + v[9] * x4 + v[10] * x5 + v[11] * x6;
108     s3 = v[12] * x1 + v[13] * x2 + v[14] * x3 + v[15] * x4 + v[16] * x5 + v[17] * x6;
109     s4 = v[18] * x1 + v[19] * x2 + v[20] * x3 + v[21] * x4 + v[22] * x5 + v[23] * x6;
110     s5 = v[24] * x1 + v[25] * x2 + v[26] * x3 + v[27] * x4 + v[28] * x5 + v[29] * x6;
111     s6 = v[30] * x1 + v[31] * x2 + v[32] * x3 + v[33] * x4 + v[34] * x5 + v[35] * x6;
112     v -= bs2;
113 
114     vi = aj + diag[i] - 1;
115     nz = diag[i] - diag[i + 1] - 1;
116     for (j = 0; j > -nz; j--) {
117       oidx = bs * vi[j];
118       x[oidx] -= v[0] * s1 + v[1] * s2 + v[2] * s3 + v[3] * s4 + v[4] * s5 + v[5] * s6;
119       x[oidx + 1] -= v[6] * s1 + v[7] * s2 + v[8] * s3 + v[9] * s4 + v[10] * s5 + v[11] * s6;
120       x[oidx + 2] -= v[12] * s1 + v[13] * s2 + v[14] * s3 + v[15] * s4 + v[16] * s5 + v[17] * s6;
121       x[oidx + 3] -= v[18] * s1 + v[19] * s2 + v[20] * s3 + v[21] * s4 + v[22] * s5 + v[23] * s6;
122       x[oidx + 4] -= v[24] * s1 + v[25] * s2 + v[26] * s3 + v[27] * s4 + v[28] * s5 + v[29] * s6;
123       x[oidx + 5] -= v[30] * s1 + v[31] * s2 + v[32] * s3 + v[33] * s4 + v[34] * s5 + v[35] * s6;
124       v -= bs2;
125     }
126     x[idx]     = s1;
127     x[1 + idx] = s2;
128     x[2 + idx] = s3;
129     x[3 + idx] = s4;
130     x[4 + idx] = s5;
131     x[5 + idx] = s6;
132     idx += bs;
133   }
134   /* backward solve the L^T */
135   for (i = n - 1; i >= 0; i--) {
136     v   = aa + bs2 * ai[i];
137     vi  = aj + ai[i];
138     nz  = ai[i + 1] - ai[i];
139     idt = bs * i;
140     s1  = x[idt];
141     s2  = x[1 + idt];
142     s3  = x[2 + idt];
143     s4  = x[3 + idt];
144     s5  = x[4 + idt];
145     s6  = x[5 + idt];
146     for (j = 0; j < nz; j++) {
147       idx = bs * vi[j];
148       x[idx] -= v[0] * s1 + v[1] * s2 + v[2] * s3 + v[3] * s4 + v[4] * s5 + v[5] * s6;
149       x[idx + 1] -= v[6] * s1 + v[7] * s2 + v[8] * s3 + v[9] * s4 + v[10] * s5 + v[11] * s6;
150       x[idx + 2] -= v[12] * s1 + v[13] * s2 + v[14] * s3 + v[15] * s4 + v[16] * s5 + v[17] * s6;
151       x[idx + 3] -= v[18] * s1 + v[19] * s2 + v[20] * s3 + v[21] * s4 + v[22] * s5 + v[23] * s6;
152       x[idx + 4] -= v[24] * s1 + v[25] * s2 + v[26] * s3 + v[27] * s4 + v[28] * s5 + v[29] * s6;
153       x[idx + 5] -= v[30] * s1 + v[31] * s2 + v[32] * s3 + v[33] * s4 + v[34] * s5 + v[35] * s6;
154       v += bs2;
155     }
156   }
157   PetscCall(VecRestoreArray(xx, &x));
158   PetscCall(PetscLogFlops(2.0 * bs2 * (a->nz) - bs * A->cmap->n));
159   PetscFunctionReturn(PETSC_SUCCESS);
160 }
161