Date: 2026-03-01T05:24:56+00:00

Actual source code: mattransposematmult.c

      1: /*
      2:   Defines matrix-matrix product routines for
      3:           C = A^T * B and C = A * B^t
      4:   with A SeqAIJ and B SeqDense
      5: */

      7: #include <../src/mat/impls/aij/seq/aij.h>
      8: #include <../src/mat/impls/dense/seq/dense.h>

     10: static PetscErrorCode MatDestroy_SeqDense_MatTransMatMult(void *data)
     11: {
     12:   Mat_MatTransMatMult *atb = (Mat_MatTransMatMult *)data;

     14:   PetscFunctionBegin;
     15:   PetscCall(MatDestroy(&atb->mA));
     16:   PetscCall(VecDestroy(&atb->bt));
     17:   PetscCall(VecDestroy(&atb->ct));
     18:   PetscCall(PetscFree(atb));
     19:   PetscFunctionReturn(PETSC_SUCCESS);
     20: }

     22: static PetscErrorCode MatTMatTMultNumeric_SeqAIJ_SeqDense(Mat, Mat, Mat);

     24: PETSC_INTERN PetscErrorCode MatTMatTMultSymbolic_SeqAIJ_SeqDense(Mat A, Mat B, PetscReal fill, Mat C)
     25: {
     26:   Mat_MatTransMatMult *atb;
     27:   PetscBool            cisdense;
     28:   PetscInt             dofm;

     30:   PetscFunctionBegin;
     31:   MatCheckProduct(C, 4);
     32:   PetscCheck(!C->product->data, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Extra product struct not empty");
     33:   PetscCheck(C->product->type == MATPRODUCT_ABt || C->product->type == MATPRODUCT_AtB, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Not for product type %s", MatProductTypes[C->product->type]);

     35:   /* create output dense matrix C */
     36:   if (C->product->type == MATPRODUCT_AtB) {
     37:     PetscCall(MatSetSizes(C, A->cmap->n, B->cmap->N, A->cmap->n, B->cmap->N));
     38:     dofm = B->cmap->n;
     39:   } else {
     40:     PetscCall(MatSetSizes(C, A->rmap->n, B->rmap->N, A->rmap->n, B->rmap->N));
     41:     dofm = B->rmap->n;
     42:   }
     43:   PetscCall(PetscObjectTypeCompareAny((PetscObject)C, &cisdense, MATSEQDENSE, MATSEQDENSECUDA, ""));
     44:   if (!cisdense) PetscCall(MatSetType(C, ((PetscObject)B)->type_name));
     45:   PetscCall(MatSetUp(C));

     47:   /* create additional data structure for the product */
     48:   PetscCall(PetscNew(&atb));
     49:   PetscCall(MatCreateMAIJ(A, dofm, &atb->mA));
     50:   PetscCall(MatCreateVecs(atb->mA, &atb->ct, &atb->bt));
     51:   C->product->data    = atb;
     52:   C->product->destroy = MatDestroy_SeqDense_MatTransMatMult;

     54:   if (C->product->type == MATPRODUCT_AtB) {
     55:     C->ops->transposematmultnumeric = MatTMatTMultNumeric_SeqAIJ_SeqDense;
     56:   } else {
     57:     C->ops->mattransposemultnumeric = MatTMatTMultNumeric_SeqAIJ_SeqDense;
     58:   }
     59:   PetscFunctionReturn(PETSC_SUCCESS);
     60: }

     62: static PetscErrorCode MatTMatTMultNumeric_SeqAIJ_SeqDense(Mat A, Mat B, Mat C)
     63: {
     64:   PetscInt             i, j, m = A->rmap->n, n = A->cmap->n, blda, clda;
     65:   PetscInt             mdof = C->cmap->N;
     66:   const PetscScalar   *Barray;
     67:   PetscScalar         *Carray;
     68:   Mat_MatTransMatMult *atb;
     69:   Vec                  bt, ct;

     71:   PetscFunctionBegin;
     72:   MatCheckProduct(C, 3);
     73:   PetscCheck(C->product->type == MATPRODUCT_ABt || C->product->type == MATPRODUCT_AtB, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Not for product type %s", MatProductTypes[C->product->type]);
     74:   atb = (Mat_MatTransMatMult *)C->product->data;
     75:   PetscCheck(atb, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Missing product struct");
     76:   bt = atb->bt;
     77:   ct = atb->ct;

     79:   PetscCall(MatDenseGetArrayRead(B, &Barray));
     80:   PetscCall(MatDenseGetLDA(B, &blda));
     81:   PetscCall(MatDenseGetArrayWrite(C, &Carray));
     82:   PetscCall(MatDenseGetLDA(C, &clda));
     83:   if (C->product->type == MATPRODUCT_AtB) { /* transpose local array of B, then copy it to vector bt */
     84:     const PetscScalar *ctarray;
     85:     PetscScalar       *btarray;

     87:     PetscCall(VecGetArrayWrite(bt, &btarray));
     88:     for (j = 0; j < mdof; j++) {
     89:       for (i = 0; i < m; i++) btarray[i * mdof + j] = Barray[j * blda + i];
     90:     }
     91:     PetscCall(VecRestoreArrayWrite(bt, &btarray));

     93:     /* compute ct = mA^T * cb */
     94:     PetscCall(MatMultTranspose(atb->mA, bt, ct));

     96:     /* transpose local array of ct to matrix C */
     97:     PetscCall(VecGetArrayRead(ct, &ctarray));
     98:     for (j = 0; j < mdof; j++) {
     99:       for (i = 0; i < n; i++) Carray[j * clda + i] = ctarray[i * mdof + j];
    100:     }
    101:     PetscCall(VecRestoreArrayRead(ct, &ctarray));
    102:   } else {
    103:     const PetscScalar *btarray;
    104:     PetscScalar       *ctarray;

    106:     if (blda == B->rmap->n) {
    107:       PetscCall(VecPlaceArray(ct, Barray));
    108:     } else {
    109:       PetscInt bn = B->cmap->n;
    110:       PetscInt bm = B->rmap->n;

    112:       PetscCall(VecGetArrayWrite(ct, &ctarray));
    113:       for (j = 0; j < bn; j++) {
    114:         for (i = 0; i < bm; i++) ctarray[j * bm + i] = Barray[j * blda + i];
    115:       }
    116:       PetscCall(VecRestoreArrayWrite(ct, &ctarray));
    117:     }

    119:     PetscCall(MatMult(atb->mA, ct, bt));
    120:     if (blda == B->rmap->n) PetscCall(VecResetArray(ct));
    121:     PetscCall(VecGetArrayRead(bt, &btarray));
    122:     for (j = 0; j < mdof; j++) {
    123:       for (i = 0; i < m; i++) Carray[j * clda + i] = btarray[i * mdof + j];
    124:     }
    125:     PetscCall(VecRestoreArrayRead(bt, &btarray));
    126:   }
    127:   PetscCall(MatDenseRestoreArrayRead(B, &Barray));
    128:   PetscCall(MatDenseRestoreArray(C, &Carray));
    129:   PetscFunctionReturn(PETSC_SUCCESS);
    130: }