Actual source code: convert.c
2: #include <petsc/private/matimpl.h>
4: /*
5: MatConvert_Basic - Converts from any input format to another format.
6: Does not do preallocation so in general will be slow
7: */
8: PETSC_INTERN PetscErrorCode MatConvert_Basic(Mat mat, MatType newtype, MatReuse reuse, Mat *newmat)
9: {
10: Mat M;
11: const PetscScalar *vwork;
12: PetscInt i, rstart, rend, nz;
13: const PetscInt *cwork;
14: PetscBool isSBAIJ;
16: PetscFunctionBegin;
17: if (!mat->ops->getrow) { /* missing get row, use matvecs */
18: PetscCall(MatConvert_Shell(mat, newtype, reuse, newmat));
19: PetscFunctionReturn(PETSC_SUCCESS);
20: }
21: PetscCall(PetscObjectTypeCompare((PetscObject)mat, MATSEQSBAIJ, &isSBAIJ));
22: if (!isSBAIJ) PetscCall(PetscObjectTypeCompare((PetscObject)mat, MATMPISBAIJ, &isSBAIJ));
23: PetscCheck(!isSBAIJ, PetscObjectComm((PetscObject)mat), PETSC_ERR_SUP, "Cannot convert from SBAIJ matrix since cannot obtain entire rows of matrix");
25: if (reuse == MAT_REUSE_MATRIX) {
26: M = *newmat;
27: } else {
28: PetscInt m, n, lm, ln;
29: PetscCall(MatGetSize(mat, &m, &n));
30: PetscCall(MatGetLocalSize(mat, &lm, &ln));
31: PetscCall(MatCreate(PetscObjectComm((PetscObject)mat), &M));
32: PetscCall(MatSetSizes(M, lm, ln, m, n));
33: PetscCall(MatSetBlockSizesFromMats(M, mat, mat));
34: PetscCall(MatSetType(M, newtype));
35: PetscCall(MatSetUp(M));
37: PetscCall(MatSetOption(M, MAT_NEW_NONZERO_LOCATION_ERR, PETSC_FALSE));
38: PetscCall(MatSetOption(M, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_FALSE));
39: PetscCall(PetscObjectTypeCompare((PetscObject)M, MATSEQSBAIJ, &isSBAIJ));
40: if (!isSBAIJ) PetscCall(PetscObjectTypeCompare((PetscObject)M, MATMPISBAIJ, &isSBAIJ));
41: if (isSBAIJ) PetscCall(MatSetOption(M, MAT_IGNORE_LOWER_TRIANGULAR, PETSC_TRUE));
42: }
44: PetscCall(MatGetOwnershipRange(mat, &rstart, &rend));
45: for (i = rstart; i < rend; i++) {
46: PetscCall(MatGetRow(mat, i, &nz, &cwork, &vwork));
47: PetscCall(MatSetValues(M, 1, &i, nz, cwork, vwork, INSERT_VALUES));
48: PetscCall(MatRestoreRow(mat, i, &nz, &cwork, &vwork));
49: }
50: PetscCall(MatAssemblyBegin(M, MAT_FINAL_ASSEMBLY));
51: PetscCall(MatAssemblyEnd(M, MAT_FINAL_ASSEMBLY));
53: if (reuse == MAT_INPLACE_MATRIX) {
54: PetscCall(MatHeaderReplace(mat, &M));
55: } else {
56: *newmat = M;
57: }
58: PetscFunctionReturn(PETSC_SUCCESS);
59: }