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: VecGetArrayRead(bb,&b);
16: VecGetArray(xx,&x);
17: t = a->solve_work;
19: ISGetIndices(isrow,&rout); r = rout;
20: ISGetIndices(iscol,&cout); c = cout;
22: /* copy the b into temp work space according to permutation */
23: ii = 0;
24: for (i=0; i<n; i++) {
25: ic = 2*c[i];
26: t[ii] = b[ic];
27: t[ii+1] = b[ic+1];
28: ii += 2;
29: }
31: /* forward solve the U^T */
32: idx = 0;
33: for (i=0; i<n; i++) {
35: v = aa + 4*diag[i];
36: /* multiply by the inverse of the block diagonal */
37: x1 = t[idx]; x2 = t[1+idx];
38: s1 = v[0]*x1 + v[1]*x2;
39: s2 = v[2]*x1 + v[3]*x2;
40: v += 4;
42: vi = aj + diag[i] + 1;
43: nz = ai[i+1] - diag[i] - 1;
44: while (nz--) {
45: oidx = 2*(*vi++);
46: t[oidx] -= v[0]*s1 + v[1]*s2;
47: t[oidx+1] -= v[2]*s1 + v[3]*s2;
48: v += 4;
49: }
50: t[idx] = s1;t[1+idx] = s2;
51: idx += 2;
52: }
53: /* backward solve the L^T */
54: for (i=n-1; i>=0; i--) {
55: v = aa + 4*diag[i] - 4;
56: vi = aj + diag[i] - 1;
57: nz = diag[i] - ai[i];
58: idt = 2*i;
59: s1 = t[idt]; s2 = t[1+idt];
60: while (nz--) {
61: idx = 2*(*vi--);
62: t[idx] -= v[0]*s1 + v[1]*s2;
63: t[idx+1] -= v[2]*s1 + v[3]*s2;
64: v -= 4;
65: }
66: }
68: /* copy t into x according to permutation */
69: ii = 0;
70: for (i=0; i<n; i++) {
71: ir = 2*r[i];
72: x[ir] = t[ii];
73: x[ir+1] = t[ii+1];
74: ii += 2;
75: }
77: ISRestoreIndices(isrow,&rout);
78: ISRestoreIndices(iscol,&cout);
79: VecRestoreArrayRead(bb,&b);
80: VecRestoreArray(xx,&x);
81: PetscLogFlops(2.0*4*(a->nz) - 2.0*A->cmap->n);
82: return 0;
83: }
85: PetscErrorCode MatSolveTranspose_SeqBAIJ_2(Mat A,Vec bb,Vec xx)
86: {
87: Mat_SeqBAIJ *a=(Mat_SeqBAIJ*)A->data;
88: IS iscol=a->col,isrow=a->row;
89: const PetscInt n =a->mbs,*vi,*ai=a->i,*aj=a->j,*diag=a->diag;
90: const PetscInt *r,*c,*rout,*cout;
91: PetscInt nz,idx,idt,j,i,oidx,ii,ic,ir;
92: const PetscInt bs =A->rmap->bs,bs2=a->bs2;
93: const MatScalar *aa=a->a,*v;
94: PetscScalar s1,s2,x1,x2,*x,*t;
95: const PetscScalar *b;
97: VecGetArrayRead(bb,&b);
98: VecGetArray(xx,&x);
99: t = a->solve_work;
101: ISGetIndices(isrow,&rout); r = rout;
102: ISGetIndices(iscol,&cout); c = cout;
104: /* copy b into temp work space according to permutation */
105: for (i=0; i<n; i++) {
106: ii = bs*i; ic = bs*c[i];
107: t[ii] = b[ic]; t[ii+1] = b[ic+1];
108: }
110: /* forward solve the U^T */
111: idx = 0;
112: for (i=0; i<n; i++) {
113: v = aa + bs2*diag[i];
114: /* multiply by the inverse of the block diagonal */
115: x1 = t[idx]; x2 = t[1+idx];
116: s1 = v[0]*x1 + v[1]*x2;
117: s2 = v[2]*x1 + v[3]*x2;
118: v -= bs2;
120: vi = aj + diag[i] - 1;
121: nz = diag[i] - diag[i+1] - 1;
122: for (j=0; j>-nz; j--) {
123: oidx = bs*vi[j];
124: t[oidx] -= v[0]*s1 + v[1]*s2;
125: t[oidx+1] -= v[2]*s1 + v[3]*s2;
126: v -= bs2;
127: }
128: t[idx] = s1;t[1+idx] = s2;
129: idx += bs;
130: }
131: /* backward solve the L^T */
132: for (i=n-1; i>=0; i--) {
133: v = aa + bs2*ai[i];
134: vi = aj + ai[i];
135: nz = ai[i+1] - ai[i];
136: idt = bs*i;
137: s1 = t[idt]; s2 = t[1+idt];
138: for (j=0; j<nz; j++) {
139: idx = bs*vi[j];
140: t[idx] -= v[0]*s1 + v[1]*s2;
141: t[idx+1] -= v[2]*s1 + v[3]*s2;
142: v += bs2;
143: }
144: }
146: /* copy t into x according to permutation */
147: for (i=0; i<n; i++) {
148: ii = bs*i; ir = bs*r[i];
149: x[ir] = t[ii]; x[ir+1] = t[ii+1];
150: }
152: ISRestoreIndices(isrow,&rout);
153: ISRestoreIndices(iscol,&cout);
154: VecRestoreArrayRead(bb,&b);
155: VecRestoreArray(xx,&x);
156: PetscLogFlops(2.0*bs2*(a->nz) - bs*A->cmap->n);
157: return 0;
158: }