1 #include <../src/mat/impls/baij/mpi/mpibaij.h> 2 3 PetscErrorCode MatGetMultiProcBlock_MPIBAIJ(Mat mat, MPI_Comm subComm, MatReuse scall, Mat *subMat) 4 { 5 Mat_MPIBAIJ *aij = (Mat_MPIBAIJ *)mat->data; 6 Mat_SeqBAIJ *aijB = (Mat_SeqBAIJ *)aij->B->data; 7 PetscMPIInt commRank, subCommSize, subCommRank; 8 PetscMPIInt *commRankMap, subRank, rank, commsize; 9 PetscInt *garrayCMap, col, i, j, *nnz, newRow, newCol, *newbRow, *newbCol, k, k1; 10 PetscInt bs = mat->rmap->bs; 11 PetscScalar *vals, *aijBvals; 12 13 PetscFunctionBegin; 14 PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)mat), &commsize)); 15 PetscCallMPI(MPI_Comm_size(subComm, &subCommSize)); 16 17 /* create subMat object with the relevant layout */ 18 if (scall == MAT_INITIAL_MATRIX) { 19 PetscCall(MatCreate(subComm, subMat)); 20 PetscCall(MatSetType(*subMat, MATMPIBAIJ)); 21 PetscCall(MatSetSizes(*subMat, mat->rmap->n, mat->cmap->n, PETSC_DECIDE, PETSC_DECIDE)); 22 PetscCall(MatSetBlockSizes(*subMat, mat->rmap->bs, mat->cmap->bs)); 23 24 /* need to setup rmap and cmap before Preallocation */ 25 PetscCall(PetscLayoutSetBlockSize((*subMat)->rmap, mat->rmap->bs)); 26 PetscCall(PetscLayoutSetBlockSize((*subMat)->cmap, mat->cmap->bs)); 27 PetscCall(PetscLayoutSetUp((*subMat)->rmap)); 28 PetscCall(PetscLayoutSetUp((*subMat)->cmap)); 29 } 30 31 /* create a map of comm_rank from subComm to comm - should commRankMap and garrayCMap be kept for reused? */ 32 PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)mat), &commRank)); 33 PetscCallMPI(MPI_Comm_rank(subComm, &subCommRank)); 34 PetscCall(PetscMalloc1(subCommSize, &commRankMap)); 35 PetscCallMPI(MPI_Allgather(&commRank, 1, MPI_INT, commRankMap, 1, MPI_INT, subComm)); 36 37 /* Traverse garray and identify blocked column indices [of offdiag mat] that 38 should be discarded. For the ones not discarded, store the newCol+1 39 value in garrayCMap */ 40 PetscCall(PetscCalloc1(aij->B->cmap->n / bs, &garrayCMap)); 41 for (i = 0; i < aij->B->cmap->n / bs; i++) { 42 col = aij->garray[i]; /* blocked column index */ 43 for (subRank = 0; subRank < subCommSize; subRank++) { 44 rank = commRankMap[subRank]; 45 if ((col >= mat->cmap->range[rank] / bs) && (col < mat->cmap->range[rank + 1] / bs)) { 46 garrayCMap[i] = (((*subMat)->cmap->range[subRank] - mat->cmap->range[rank]) / bs + col + 1); 47 break; 48 } 49 } 50 } 51 52 if (scall == MAT_INITIAL_MATRIX) { 53 /* Now compute preallocation for the offdiag mat */ 54 PetscCall(PetscCalloc1(aij->B->rmap->n / bs, &nnz)); 55 for (i = 0; i < aij->B->rmap->n / bs; i++) { 56 for (j = aijB->i[i]; j < aijB->i[i + 1]; j++) { 57 if (garrayCMap[aijB->j[j]]) nnz[i]++; 58 } 59 } 60 PetscCall(MatMPIBAIJSetPreallocation(*(subMat), bs, 0, NULL, 0, nnz)); 61 62 /* reuse diag block with the new submat */ 63 PetscCall(MatDestroy(&((Mat_MPIBAIJ *)((*subMat)->data))->A)); 64 65 ((Mat_MPIBAIJ *)((*subMat)->data))->A = aij->A; 66 67 PetscCall(PetscObjectReference((PetscObject)aij->A)); 68 } else if (((Mat_MPIBAIJ *)(*subMat)->data)->A != aij->A) { 69 PetscObject obj = (PetscObject)((Mat_MPIBAIJ *)((*subMat)->data))->A; 70 71 PetscCall(PetscObjectReference(obj)); 72 73 ((Mat_MPIBAIJ *)((*subMat)->data))->A = aij->A; 74 75 PetscCall(PetscObjectReference((PetscObject)aij->A)); 76 } 77 78 /* Now traverse aij->B and insert values into subMat */ 79 /* Does not need PetscShmgetAllocateArray() since temporary */ 80 PetscCall(PetscMalloc3(bs, &newbRow, bs, &newbCol, bs * bs, &vals)); 81 for (i = 0; i < aij->B->rmap->n / bs; i++) { 82 newRow = (*subMat)->rmap->range[subCommRank] + i * bs; 83 for (j = aijB->i[i]; j < aijB->i[i + 1]; j++) { 84 newCol = garrayCMap[aijB->j[j]]; 85 if (newCol) { 86 newCol--; /* remove the increment */ 87 newCol *= bs; 88 for (k = 0; k < bs; k++) { 89 newbRow[k] = newRow + k; 90 newbCol[k] = newCol + k; 91 } 92 /* copy column-oriented aijB->a into row-oriented vals */ 93 aijBvals = aijB->a + j * bs * bs; 94 for (k1 = 0; k1 < bs; k1++) { 95 for (k = 0; k < bs; k++) vals[k1 + k * bs] = *aijBvals++; 96 } 97 PetscCall(MatSetValues(*subMat, bs, newbRow, bs, newbCol, vals, INSERT_VALUES)); 98 } 99 } 100 } 101 PetscCall(MatAssemblyBegin(*subMat, MAT_FINAL_ASSEMBLY)); 102 PetscCall(MatAssemblyEnd(*subMat, MAT_FINAL_ASSEMBLY)); 103 104 /* deallocate temporary data */ 105 PetscCall(PetscFree3(newbRow, newbCol, vals)); 106 PetscCall(PetscFree(commRankMap)); 107 PetscCall(PetscFree(garrayCMap)); 108 if (scall == MAT_INITIAL_MATRIX) PetscCall(PetscFree(nnz)); 109 PetscFunctionReturn(PETSC_SUCCESS); 110 } 111