1 #include <../src/mat/impls/baij/seq/baij.h> 2 #include <petsc/private/kernels/blockinvert.h> 3 4 PetscErrorCode MatSolveTranspose_SeqBAIJ_1(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 *rout, *cout, *r, *c, *adiag = a->diag, *ai = a->i, *aj = a->j, *vi; 9 PetscInt i, n = a->mbs, j; 10 PetscInt nz; 11 PetscScalar *x, *tmp, s1; 12 const MatScalar *aa = a->a, *v; 13 const PetscScalar *b; 14 15 PetscFunctionBegin; 16 PetscCall(VecGetArrayRead(bb, &b)); 17 PetscCall(VecGetArray(xx, &x)); 18 tmp = 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 for (i = 0; i < n; i++) tmp[i] = b[c[i]]; 27 28 /* forward solve the U^T */ 29 for (i = 0; i < n; i++) { 30 v = aa + adiag[i + 1] + 1; 31 vi = aj + adiag[i + 1] + 1; 32 nz = adiag[i] - adiag[i + 1] - 1; 33 s1 = tmp[i]; 34 s1 *= v[nz]; /* multiply by inverse of diagonal entry */ 35 for (j = 0; j < nz; j++) tmp[vi[j]] -= s1 * v[j]; 36 tmp[i] = s1; 37 } 38 39 /* backward solve the L^T */ 40 for (i = n - 1; i >= 0; i--) { 41 v = aa + ai[i]; 42 vi = aj + ai[i]; 43 nz = ai[i + 1] - ai[i]; 44 s1 = tmp[i]; 45 for (j = 0; j < nz; j++) tmp[vi[j]] -= s1 * v[j]; 46 } 47 48 /* copy tmp into x according to permutation */ 49 for (i = 0; i < n; i++) x[r[i]] = tmp[i]; 50 51 PetscCall(ISRestoreIndices(isrow, &rout)); 52 PetscCall(ISRestoreIndices(iscol, &cout)); 53 PetscCall(VecRestoreArrayRead(bb, &b)); 54 PetscCall(VecRestoreArray(xx, &x)); 55 56 PetscCall(PetscLogFlops(2.0 * a->nz - A->cmap->n)); 57 PetscFunctionReturn(PETSC_SUCCESS); 58 } 59 60 PetscErrorCode MatSolveTranspose_SeqBAIJ_1_inplace(Mat A, Vec bb, Vec xx) 61 { 62 Mat_SeqBAIJ *a = (Mat_SeqBAIJ *)A->data; 63 IS iscol = a->col, isrow = a->row; 64 const PetscInt *r, *c, *rout, *cout; 65 const PetscInt *diag = a->diag, n = a->mbs, *vi, *ai = a->i, *aj = a->j; 66 PetscInt i, nz; 67 const MatScalar *aa = a->a, *v; 68 PetscScalar s1, *x, *t; 69 const PetscScalar *b; 70 71 PetscFunctionBegin; 72 PetscCall(VecGetArrayRead(bb, &b)); 73 PetscCall(VecGetArray(xx, &x)); 74 t = a->solve_work; 75 76 PetscCall(ISGetIndices(isrow, &rout)); 77 r = rout; 78 PetscCall(ISGetIndices(iscol, &cout)); 79 c = cout; 80 81 /* copy the b into temp work space according to permutation */ 82 for (i = 0; i < n; i++) t[i] = b[c[i]]; 83 84 /* forward solve the U^T */ 85 for (i = 0; i < n; i++) { 86 v = aa + diag[i]; 87 /* multiply by the inverse of the block diagonal */ 88 s1 = (*v++) * t[i]; 89 vi = aj + diag[i] + 1; 90 nz = ai[i + 1] - diag[i] - 1; 91 while (nz--) t[*vi++] -= (*v++) * s1; 92 t[i] = s1; 93 } 94 /* backward solve the L^T */ 95 for (i = n - 1; i >= 0; i--) { 96 v = aa + diag[i] - 1; 97 vi = aj + diag[i] - 1; 98 nz = diag[i] - ai[i]; 99 s1 = t[i]; 100 while (nz--) t[*vi--] -= (*v--) * s1; 101 } 102 103 /* copy t into x according to permutation */ 104 for (i = 0; i < n; i++) x[r[i]] = t[i]; 105 106 PetscCall(ISRestoreIndices(isrow, &rout)); 107 PetscCall(ISRestoreIndices(iscol, &cout)); 108 PetscCall(VecRestoreArrayRead(bb, &b)); 109 PetscCall(VecRestoreArray(xx, &x)); 110 PetscCall(PetscLogFlops(2.0 * (a->nz) - A->cmap->n)); 111 PetscFunctionReturn(PETSC_SUCCESS); 112 } 113