xref: /petsc/src/mat/impls/baij/seq/baijsolvtrannat6.c (revision 58d68138c660dfb4e9f5b03334792cd4f2ffd7cc)
1 #include <../src/mat/impls/baij/seq/baij.h>
2 
3 PetscErrorCode MatSolveTranspose_SeqBAIJ_6_NaturalOrdering_inplace(Mat A, Vec bb, Vec xx) {
4   Mat_SeqBAIJ     *a    = (Mat_SeqBAIJ *)A->data;
5   const PetscInt  *diag = a->diag, n = a->mbs, *vi, *ai = a->i, *aj = a->j;
6   PetscInt         i, nz, idx, idt, oidx;
7   const MatScalar *aa = a->a, *v;
8   PetscScalar      s1, s2, s3, s4, s5, s6, x1, x2, x3, x4, x5, x6, *x;
9 
10   PetscFunctionBegin;
11   PetscCall(VecCopy(bb, xx));
12   PetscCall(VecGetArray(xx, &x));
13 
14   /* forward solve the U^T */
15   idx = 0;
16   for (i = 0; i < n; i++) {
17     v  = aa + 36 * diag[i];
18     /* multiply by the inverse of the block diagonal */
19     x1 = x[idx];
20     x2 = x[1 + idx];
21     x3 = x[2 + idx];
22     x4 = x[3 + idx];
23     x5 = x[4 + idx];
24     x6 = x[5 + idx];
25     s1 = v[0] * x1 + v[1] * x2 + v[2] * x3 + v[3] * x4 + v[4] * x5 + v[5] * x6;
26     s2 = v[6] * x1 + v[7] * x2 + v[8] * x3 + v[9] * x4 + v[10] * x5 + v[11] * x6;
27     s3 = v[12] * x1 + v[13] * x2 + v[14] * x3 + v[15] * x4 + v[16] * x5 + v[17] * x6;
28     s4 = v[18] * x1 + v[19] * x2 + v[20] * x3 + v[21] * x4 + v[22] * x5 + v[23] * x6;
29     s5 = v[24] * x1 + v[25] * x2 + v[26] * x3 + v[27] * x4 + v[28] * x5 + v[29] * x6;
30     s6 = v[30] * x1 + v[31] * x2 + v[32] * x3 + v[33] * x4 + v[34] * x5 + v[35] * x6;
31     v += 36;
32 
33     vi = aj + diag[i] + 1;
34     nz = ai[i + 1] - diag[i] - 1;
35     while (nz--) {
36       oidx = 6 * (*vi++);
37       x[oidx] -= v[0] * s1 + v[1] * s2 + v[2] * s3 + v[3] * s4 + v[4] * s5 + v[5] * s6;
38       x[oidx + 1] -= v[6] * s1 + v[7] * s2 + v[8] * s3 + v[9] * s4 + v[10] * s5 + v[11] * s6;
39       x[oidx + 2] -= v[12] * s1 + v[13] * s2 + v[14] * s3 + v[15] * s4 + v[16] * s5 + v[17] * s6;
40       x[oidx + 3] -= v[18] * s1 + v[19] * s2 + v[20] * s3 + v[21] * s4 + v[22] * s5 + v[23] * s6;
41       x[oidx + 4] -= v[24] * s1 + v[25] * s2 + v[26] * s3 + v[27] * s4 + v[28] * s5 + v[29] * s6;
42       x[oidx + 5] -= v[30] * s1 + v[31] * s2 + v[32] * s3 + v[33] * s4 + v[34] * s5 + v[35] * s6;
43       v += 36;
44     }
45     x[idx]     = s1;
46     x[1 + idx] = s2;
47     x[2 + idx] = s3;
48     x[3 + idx] = s4;
49     x[4 + idx] = s5;
50     x[5 + idx] = s6;
51     idx += 6;
52   }
53   /* backward solve the L^T */
54   for (i = n - 1; i >= 0; i--) {
55     v   = aa + 36 * diag[i] - 36;
56     vi  = aj + diag[i] - 1;
57     nz  = diag[i] - ai[i];
58     idt = 6 * i;
59     s1  = x[idt];
60     s2  = x[1 + idt];
61     s3  = x[2 + idt];
62     s4  = x[3 + idt];
63     s5  = x[4 + idt];
64     s6  = x[5 + idt];
65     while (nz--) {
66       idx = 6 * (*vi--);
67       x[idx] -= v[0] * s1 + v[1] * s2 + v[2] * s3 + v[3] * s4 + v[4] * s5 + v[5] * s6;
68       x[idx + 1] -= v[6] * s1 + v[7] * s2 + v[8] * s3 + v[9] * s4 + v[10] * s5 + v[11] * s6;
69       x[idx + 2] -= v[12] * s1 + v[13] * s2 + v[14] * s3 + v[15] * s4 + v[16] * s5 + v[17] * s6;
70       x[idx + 3] -= v[18] * s1 + v[19] * s2 + v[20] * s3 + v[21] * s4 + v[22] * s5 + v[23] * s6;
71       x[idx + 4] -= v[24] * s1 + v[25] * s2 + v[26] * s3 + v[27] * s4 + v[28] * s5 + v[29] * s6;
72       x[idx + 5] -= v[30] * s1 + v[31] * s2 + v[32] * s3 + v[33] * s4 + v[34] * s5 + v[35] * s6;
73       v -= 36;
74     }
75   }
76   PetscCall(VecRestoreArray(xx, &x));
77   PetscCall(PetscLogFlops(2.0 * 36 * (a->nz) - 6.0 * A->cmap->n));
78   PetscFunctionReturn(0);
79 }
80 
81 PetscErrorCode MatSolveTranspose_SeqBAIJ_6_NaturalOrdering(Mat A, Vec bb, Vec xx) {
82   Mat_SeqBAIJ     *a = (Mat_SeqBAIJ *)A->data;
83   const PetscInt   n = a->mbs, *vi, *ai = a->i, *aj = a->j, *diag = a->diag;
84   PetscInt         nz, idx, idt, j, i, oidx;
85   const PetscInt   bs = A->rmap->bs, bs2 = a->bs2;
86   const MatScalar *aa = a->a, *v;
87   PetscScalar      s1, s2, s3, s4, s5, s6, x1, x2, x3, x4, x5, x6, *x;
88 
89   PetscFunctionBegin;
90   PetscCall(VecCopy(bb, xx));
91   PetscCall(VecGetArray(xx, &x));
92 
93   /* forward solve the U^T */
94   idx = 0;
95   for (i = 0; i < n; i++) {
96     v  = aa + bs2 * diag[i];
97     /* multiply by the inverse of the block diagonal */
98     x1 = x[idx];
99     x2 = x[1 + idx];
100     x3 = x[2 + idx];
101     x4 = x[3 + idx];
102     x5 = x[4 + idx];
103     x6 = x[5 + idx];
104     s1 = v[0] * x1 + v[1] * x2 + v[2] * x3 + v[3] * x4 + v[4] * x5 + v[5] * x6;
105     s2 = v[6] * x1 + v[7] * x2 + v[8] * x3 + v[9] * x4 + v[10] * x5 + v[11] * x6;
106     s3 = v[12] * x1 + v[13] * x2 + v[14] * x3 + v[15] * x4 + v[16] * x5 + v[17] * x6;
107     s4 = v[18] * x1 + v[19] * x2 + v[20] * x3 + v[21] * x4 + v[22] * x5 + v[23] * x6;
108     s5 = v[24] * x1 + v[25] * x2 + v[26] * x3 + v[27] * x4 + v[28] * x5 + v[29] * x6;
109     s6 = v[30] * x1 + v[31] * x2 + v[32] * x3 + v[33] * x4 + v[34] * x5 + v[35] * x6;
110     v -= bs2;
111 
112     vi = aj + diag[i] - 1;
113     nz = diag[i] - diag[i + 1] - 1;
114     for (j = 0; j > -nz; j--) {
115       oidx = bs * vi[j];
116       x[oidx] -= v[0] * s1 + v[1] * s2 + v[2] * s3 + v[3] * s4 + v[4] * s5 + v[5] * s6;
117       x[oidx + 1] -= v[6] * s1 + v[7] * s2 + v[8] * s3 + v[9] * s4 + v[10] * s5 + v[11] * s6;
118       x[oidx + 2] -= v[12] * s1 + v[13] * s2 + v[14] * s3 + v[15] * s4 + v[16] * s5 + v[17] * s6;
119       x[oidx + 3] -= v[18] * s1 + v[19] * s2 + v[20] * s3 + v[21] * s4 + v[22] * s5 + v[23] * s6;
120       x[oidx + 4] -= v[24] * s1 + v[25] * s2 + v[26] * s3 + v[27] * s4 + v[28] * s5 + v[29] * s6;
121       x[oidx + 5] -= v[30] * s1 + v[31] * s2 + v[32] * s3 + v[33] * s4 + v[34] * s5 + v[35] * s6;
122       v -= bs2;
123     }
124     x[idx]     = s1;
125     x[1 + idx] = s2;
126     x[2 + idx] = s3;
127     x[3 + idx] = s4;
128     x[4 + idx] = s5;
129     x[5 + idx] = s6;
130     idx += bs;
131   }
132   /* backward solve the L^T */
133   for (i = n - 1; i >= 0; i--) {
134     v   = aa + bs2 * ai[i];
135     vi  = aj + ai[i];
136     nz  = ai[i + 1] - ai[i];
137     idt = bs * i;
138     s1  = x[idt];
139     s2  = x[1 + idt];
140     s3  = x[2 + idt];
141     s4  = x[3 + idt];
142     s5  = x[4 + idt];
143     s6  = x[5 + idt];
144     for (j = 0; j < nz; j++) {
145       idx = bs * vi[j];
146       x[idx] -= v[0] * s1 + v[1] * s2 + v[2] * s3 + v[3] * s4 + v[4] * s5 + v[5] * s6;
147       x[idx + 1] -= v[6] * s1 + v[7] * s2 + v[8] * s3 + v[9] * s4 + v[10] * s5 + v[11] * s6;
148       x[idx + 2] -= v[12] * s1 + v[13] * s2 + v[14] * s3 + v[15] * s4 + v[16] * s5 + v[17] * s6;
149       x[idx + 3] -= v[18] * s1 + v[19] * s2 + v[20] * s3 + v[21] * s4 + v[22] * s5 + v[23] * s6;
150       x[idx + 4] -= v[24] * s1 + v[25] * s2 + v[26] * s3 + v[27] * s4 + v[28] * s5 + v[29] * s6;
151       x[idx + 5] -= v[30] * s1 + v[31] * s2 + v[32] * s3 + v[33] * s4 + v[34] * s5 + v[35] * s6;
152       v += bs2;
153     }
154   }
155   PetscCall(VecRestoreArray(xx, &x));
156   PetscCall(PetscLogFlops(2.0 * bs2 * (a->nz) - bs * A->cmap->n));
157   PetscFunctionReturn(0);
158 }
159