Actual source code: baijsolvtrannat2.c
1: #include <../src/mat/impls/baij/seq/baij.h>
3: PetscErrorCode MatSolveTranspose_SeqBAIJ_2_NaturalOrdering_inplace(Mat A,Vec bb,Vec xx)
4: {
5: Mat_SeqBAIJ *a=(Mat_SeqBAIJ*)A->data;
6: PetscInt i,nz,idx,idt,oidx;
7: const PetscInt *diag = a->diag,*vi,n=a->mbs,*ai=a->i,*aj=a->j;
8: const MatScalar *aa =a->a,*v;
9: PetscScalar s1,s2,x1,x2,*x;
11: VecCopy(bb,xx);
12: VecGetArray(xx,&x);
14: /* forward solve the U^T */
15: idx = 0;
16: for (i=0; i<n; i++) {
18: v = aa + 4*diag[i];
19: /* multiply by the inverse of the block diagonal */
20: x1 = x[idx]; x2 = x[1+idx];
21: s1 = v[0]*x1 + v[1]*x2;
22: s2 = v[2]*x1 + v[3]*x2;
23: v += 4;
25: vi = aj + diag[i] + 1;
26: nz = ai[i+1] - diag[i] - 1;
27: while (nz--) {
28: oidx = 2*(*vi++);
29: x[oidx] -= v[0]*s1 + v[1]*s2;
30: x[oidx+1] -= v[2]*s1 + v[3]*s2;
31: v += 4;
32: }
33: x[idx] = s1;x[1+idx] = s2;
34: idx += 2;
35: }
36: /* backward solve the L^T */
37: for (i=n-1; i>=0; i--) {
38: v = aa + 4*diag[i] - 4;
39: vi = aj + diag[i] - 1;
40: nz = diag[i] - ai[i];
41: idt = 2*i;
42: s1 = x[idt]; s2 = x[1+idt];
43: while (nz--) {
44: idx = 2*(*vi--);
45: x[idx] -= v[0]*s1 + v[1]*s2;
46: x[idx+1] -= v[2]*s1 + v[3]*s2;
47: v -= 4;
48: }
49: }
50: VecRestoreArray(xx,&x);
51: PetscLogFlops(2.0*4.0*(a->nz) - 2.0*A->cmap->n);
52: return 0;
53: }
55: PetscErrorCode MatSolveTranspose_SeqBAIJ_2_NaturalOrdering(Mat A,Vec bb,Vec xx)
56: {
57: Mat_SeqBAIJ *a=(Mat_SeqBAIJ*)A->data;
58: const PetscInt n=a->mbs,*vi,*ai=a->i,*aj=a->j,*diag=a->diag;
59: PetscInt nz,idx,idt,j,i,oidx;
60: const PetscInt bs =A->rmap->bs,bs2=a->bs2;
61: const MatScalar *aa=a->a,*v;
62: PetscScalar s1,s2,x1,x2,*x;
64: VecCopy(bb,xx);
65: VecGetArray(xx,&x);
67: /* forward solve the U^T */
68: idx = 0;
69: for (i=0; i<n; i++) {
70: v = aa + bs2*diag[i];
71: /* multiply by the inverse of the block diagonal */
72: x1 = x[idx]; x2 = x[1+idx];
73: s1 = v[0]*x1 + v[1]*x2;
74: s2 = v[2]*x1 + v[3]*x2;
75: v -= bs2;
77: vi = aj + diag[i] - 1;
78: nz = diag[i] - diag[i+1] - 1;
79: for (j=0; j>-nz; j--) {
80: oidx = bs*vi[j];
81: x[oidx] -= v[0]*s1 + v[1]*s2;
82: x[oidx+1] -= v[2]*s1 + v[3]*s2;
83: v -= bs2;
84: }
85: x[idx] = s1;x[1+idx] = s2;
86: idx += bs;
87: }
88: /* backward solve the L^T */
89: for (i=n-1; i>=0; i--) {
90: v = aa + bs2*ai[i];
91: vi = aj + ai[i];
92: nz = ai[i+1] - ai[i];
93: idt = bs*i;
94: s1 = x[idt]; s2 = x[1+idt];
95: for (j=0; j<nz; j++) {
96: idx = bs*vi[j];
97: x[idx] -= v[0]*s1 + v[1]*s2;
98: x[idx+1] -= v[2]*s1 + v[3]*s2;
99: v += bs2;
100: }
101: }
102: VecRestoreArray(xx,&x);
103: PetscLogFlops(2.0*bs2*(a->nz) - bs*A->cmap->n);
104: return 0;
105: }