Date: 2026-05-01T06:11:57+00:00

Actual source code: baijsolvtrann.c

      1: #include <../src/mat/impls/baij/seq/baij.h>
      2: #include <petsc/private/kernels/blockinvert.h>

      4: PetscErrorCode MatSolveTranspose_SeqBAIJ_N_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, *ai = a->i, *aj = a->j, *vi;
      9:   PetscInt           i, nz, j;
     10:   const PetscInt     n = a->mbs, bs = A->rmap->bs, bs2 = a->bs2;
     11:   const MatScalar   *aa = a->a, *v;
     12:   PetscScalar       *x, *t, *ls;
     13:   const PetscScalar *b;

     15:   PetscFunctionBegin;
     16:   PetscCheck(bs > 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Expected bs %" PetscInt_FMT " > 0", bs);
     17:   PetscCall(VecGetArrayRead(bb, &b));
     18:   PetscCall(VecGetArray(xx, &x));
     19:   t = a->solve_work;

     21:   PetscCall(ISGetIndices(isrow, &rout));
     22:   r = rout;
     23:   PetscCall(ISGetIndices(iscol, &cout));
     24:   c = cout;

     26:   /* copy the b into temp work space according to permutation */
     27:   for (i = 0; i < n; i++) {
     28:     for (j = 0; j < bs; j++) t[i * bs + j] = b[c[i] * bs + j];
     29:   }

     31:   /* forward solve the upper triangular transpose */
     32:   ls = a->solve_work + A->cmap->n;
     33:   for (i = 0; i < n; i++) {
     34:     PetscCall(PetscArraycpy(ls, t + i * bs, bs));
     35:     PetscKernel_w_gets_transA_times_v(bs, ls, aa + bs2 * a->diag[i], t + i * bs);
     36:     v  = aa + bs2 * (a->diag[i] + 1);
     37:     vi = aj + a->diag[i] + 1;
     38:     nz = ai[i + 1] - a->diag[i] - 1;
     39:     while (nz--) {
     40:       PetscKernel_v_gets_v_minus_transA_times_w(bs, t + bs * (*vi++), v, t + i * bs);
     41:       v += bs2;
     42:     }
     43:   }

     45:   /* backward solve the lower triangular transpose */
     46:   for (i = n - 1; i >= 0; i--) {
     47:     v  = aa + bs2 * ai[i];
     48:     vi = aj + ai[i];
     49:     nz = a->diag[i] - ai[i];
     50:     while (nz--) {
     51:       PetscKernel_v_gets_v_minus_transA_times_w(bs, t + bs * (*vi++), v, t + i * bs);
     52:       v += bs2;
     53:     }
     54:   }

     56:   /* copy t into x according to permutation */
     57:   for (i = 0; i < n; i++) {
     58:     for (j = 0; j < bs; j++) x[bs * r[i] + j] = t[bs * i + j];
     59:   }

     61:   PetscCall(ISRestoreIndices(isrow, &rout));
     62:   PetscCall(ISRestoreIndices(iscol, &cout));
     63:   PetscCall(VecRestoreArrayRead(bb, &b));
     64:   PetscCall(VecRestoreArray(xx, &x));
     65:   PetscCall(PetscLogFlops(2.0 * (a->bs2) * (a->nz) - A->rmap->bs * A->cmap->n));
     66:   PetscFunctionReturn(PETSC_SUCCESS);
     67: }

     69: PetscErrorCode MatSolveTranspose_SeqBAIJ_N(Mat A, Vec bb, Vec xx)
     70: {
     71:   Mat_SeqBAIJ       *a     = (Mat_SeqBAIJ *)A->data;
     72:   IS                 iscol = a->col, isrow = a->row;
     73:   const PetscInt    *r, *c, *rout, *cout;
     74:   const PetscInt     n = a->mbs, *ai = a->i, *aj = a->j, *vi, *diag = a->diag;
     75:   PetscInt           i, j, nz;
     76:   const PetscInt     bs = A->rmap->bs, bs2 = a->bs2;
     77:   const MatScalar   *aa = a->a, *v;
     78:   PetscScalar       *x, *t, *ls;
     79:   const PetscScalar *b;

     81:   PetscFunctionBegin;
     82:   PetscCheck(bs > 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Expected bs %" PetscInt_FMT " > 0", bs);
     83:   PetscCall(VecGetArrayRead(bb, &b));
     84:   PetscCall(VecGetArray(xx, &x));
     85:   t = a->solve_work;

     87:   PetscCall(ISGetIndices(isrow, &rout));
     88:   r = rout;
     89:   PetscCall(ISGetIndices(iscol, &cout));
     90:   c = cout;

     92:   /* copy the b into temp work space according to permutation */
     93:   for (i = 0; i < n; i++) {
     94:     for (j = 0; j < bs; j++) t[i * bs + j] = b[c[i] * bs + j];
     95:   }

     97:   /* forward solve the upper triangular transpose */
     98:   ls = a->solve_work + A->cmap->n;
     99:   for (i = 0; i < n; i++) {
    100:     PetscCall(PetscArraycpy(ls, t + i * bs, bs));
    101:     PetscKernel_w_gets_transA_times_v(bs, ls, aa + bs2 * diag[i], t + i * bs);
    102:     v  = aa + bs2 * (diag[i] - 1);
    103:     vi = aj + diag[i] - 1;
    104:     nz = diag[i] - diag[i + 1] - 1;
    105:     for (j = 0; j > -nz; j--) {
    106:       PetscKernel_v_gets_v_minus_transA_times_w(bs, t + bs * (vi[j]), v, t + i * bs);
    107:       v -= bs2;
    108:     }
    109:   }

    111:   /* backward solve the lower triangular transpose */
    112:   for (i = n - 1; i >= 0; i--) {
    113:     v  = aa + bs2 * ai[i];
    114:     vi = aj + ai[i];
    115:     nz = ai[i + 1] - ai[i];
    116:     for (j = 0; j < nz; j++) {
    117:       PetscKernel_v_gets_v_minus_transA_times_w(bs, t + bs * (vi[j]), v, t + i * bs);
    118:       v += bs2;
    119:     }
    120:   }

    122:   /* copy t into x according to permutation */
    123:   for (i = 0; i < n; i++) {
    124:     for (j = 0; j < bs; j++) x[bs * r[i] + j] = t[bs * i + j];
    125:   }

    127:   PetscCall(ISRestoreIndices(isrow, &rout));
    128:   PetscCall(ISRestoreIndices(iscol, &cout));
    129:   PetscCall(VecRestoreArrayRead(bb, &b));
    130:   PetscCall(VecRestoreArray(xx, &x));
    131:   PetscCall(PetscLogFlops(2.0 * (a->bs2) * (a->nz) - A->rmap->bs * A->cmap->n));
    132:   PetscFunctionReturn(PETSC_SUCCESS);
    133: }