1 #include <../src/mat/impls/baij/mpi/mpibaij.h> 2 3 PetscErrorCode MatGetMultiProcBlock_MPIBAIJ(Mat mat, MPI_Comm subComm, MatReuse scall, Mat *subMat) { 4 Mat_MPIBAIJ *aij = (Mat_MPIBAIJ *)mat->data; 5 Mat_SeqBAIJ *aijB = (Mat_SeqBAIJ *)aij->B->data; 6 PetscMPIInt commRank, subCommSize, subCommRank; 7 PetscMPIInt *commRankMap, subRank, rank, commsize; 8 PetscInt *garrayCMap, col, i, j, *nnz, newRow, newCol, *newbRow, *newbCol, k, k1; 9 PetscInt bs = mat->rmap->bs; 10 PetscScalar *vals, *aijBvals; 11 12 PetscFunctionBegin; 13 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &commsize)); 14 PetscCallMPI(MPI_Comm_size(subComm, &subCommSize)); 15 16 /* create subMat object with the relevant layout */ 17 if (scall == MAT_INITIAL_MATRIX) { 18 PetscCall(MatCreate(subComm, subMat)); 19 PetscCall(MatSetType(*subMat, MATMPIBAIJ)); 20 PetscCall(MatSetSizes(*subMat, mat->rmap->n, mat->cmap->n, PETSC_DECIDE, PETSC_DECIDE)); 21 PetscCall(MatSetBlockSizes(*subMat, mat->rmap->bs, mat->cmap->bs)); 22 23 /* need to setup rmap and cmap before Preallocation */ 24 PetscCall(PetscLayoutSetBlockSize((*subMat)->rmap, mat->rmap->bs)); 25 PetscCall(PetscLayoutSetBlockSize((*subMat)->cmap, mat->cmap->bs)); 26 PetscCall(PetscLayoutSetUp((*subMat)->rmap)); 27 PetscCall(PetscLayoutSetUp((*subMat)->cmap)); 28 } 29 30 /* create a map of comm_rank from subComm to comm - should commRankMap and garrayCMap be kept for reused? */ 31 PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)mat), &commRank)); 32 PetscCallMPI(MPI_Comm_rank(subComm, &subCommRank)); 33 PetscCall(PetscMalloc1(subCommSize, &commRankMap)); 34 PetscCallMPI(MPI_Allgather(&commRank, 1, MPI_INT, commRankMap, 1, MPI_INT, subComm)); 35 36 /* Traverse garray and identify blocked column indices [of offdiag mat] that 37 should be discarded. For the ones not discarded, store the newCol+1 38 value in garrayCMap */ 39 PetscCall(PetscCalloc1(aij->B->cmap->n / bs, &garrayCMap)); 40 for (i = 0; i < aij->B->cmap->n / bs; i++) { 41 col = aij->garray[i]; /* blocked column index */ 42 for (subRank = 0; subRank < subCommSize; subRank++) { 43 rank = commRankMap[subRank]; 44 if ((col >= mat->cmap->range[rank] / bs) && (col < mat->cmap->range[rank + 1] / bs)) { 45 garrayCMap[i] = (((*subMat)->cmap->range[subRank] - mat->cmap->range[rank]) / bs + col + 1); 46 break; 47 } 48 } 49 } 50 51 if (scall == MAT_INITIAL_MATRIX) { 52 /* Now compute preallocation for the offdiag mat */ 53 PetscCall(PetscCalloc1(aij->B->rmap->n / bs, &nnz)); 54 for (i = 0; i < aij->B->rmap->n / bs; i++) { 55 for (j = aijB->i[i]; j < aijB->i[i + 1]; j++) { 56 if (garrayCMap[aijB->j[j]]) nnz[i]++; 57 } 58 } 59 PetscCall(MatMPIBAIJSetPreallocation(*(subMat), bs, 0, NULL, 0, nnz)); 60 61 /* reuse diag block with the new submat */ 62 PetscCall(MatDestroy(&((Mat_MPIBAIJ *)((*subMat)->data))->A)); 63 64 ((Mat_MPIBAIJ *)((*subMat)->data))->A = aij->A; 65 66 PetscCall(PetscObjectReference((PetscObject)aij->A)); 67 } else if (((Mat_MPIBAIJ *)(*subMat)->data)->A != aij->A) { 68 PetscObject obj = (PetscObject)((Mat_MPIBAIJ *)((*subMat)->data))->A; 69 70 PetscCall(PetscObjectReference((PetscObject)obj)); 71 72 ((Mat_MPIBAIJ *)((*subMat)->data))->A = aij->A; 73 74 PetscCall(PetscObjectReference((PetscObject)aij->A)); 75 } 76 77 /* Now traverse aij->B and insert values into subMat */ 78 PetscCall(PetscMalloc3(bs, &newbRow, bs, &newbCol, bs * bs, &vals)); 79 for (i = 0; i < aij->B->rmap->n / bs; i++) { 80 newRow = (*subMat)->rmap->range[subCommRank] + i * bs; 81 for (j = aijB->i[i]; j < aijB->i[i + 1]; j++) { 82 newCol = garrayCMap[aijB->j[j]]; 83 if (newCol) { 84 newCol--; /* remove the increment */ 85 newCol *= bs; 86 for (k = 0; k < bs; k++) { 87 newbRow[k] = newRow + k; 88 newbCol[k] = newCol + k; 89 } 90 /* copy column-oriented aijB->a into row-oriented vals */ 91 aijBvals = aijB->a + j * bs * bs; 92 for (k1 = 0; k1 < bs; k1++) { 93 for (k = 0; k < bs; k++) { vals[k1 + k * bs] = *aijBvals++; } 94 } 95 PetscCall(MatSetValues(*subMat, bs, newbRow, bs, newbCol, vals, INSERT_VALUES)); 96 } 97 } 98 } 99 PetscCall(MatAssemblyBegin(*subMat, MAT_FINAL_ASSEMBLY)); 100 PetscCall(MatAssemblyEnd(*subMat, MAT_FINAL_ASSEMBLY)); 101 102 /* deallocate temporary data */ 103 PetscCall(PetscFree3(newbRow, newbCol, vals)); 104 PetscCall(PetscFree(commRankMap)); 105 PetscCall(PetscFree(garrayCMap)); 106 if (scall == MAT_INITIAL_MATRIX) { PetscCall(PetscFree(nnz)); } 107 PetscFunctionReturn(0); 108 } 109