1 #include <../src/mat/impls/baij/mpi/mpibaij.h>
2
MatGetMultiProcBlock_MPIBAIJ(Mat mat,MPI_Comm subComm,MatReuse scall,Mat * subMat)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