Actual source code: convert.c
petsc-3.14.6 2021-03-30
2: #include <petsc/private/matimpl.h>
4: /*
5: MatConvert_Basic - Converts from any input format to another format. For
6: parallel formats, the new matrix distribution is determined by PETSc.
8: Does not do preallocation so in general will be slow
9: */
10: PETSC_INTERN PetscErrorCode MatConvert_Basic(Mat mat, MatType newtype,MatReuse reuse,Mat *newmat)
11: {
12: Mat M;
13: const PetscScalar *vwork;
14: PetscErrorCode ierr;
15: PetscInt i,rstart,rend,nz;
16: const PetscInt *cwork;
17: PetscBool isSBAIJ;
20: PetscObjectTypeCompare((PetscObject)mat,MATSEQSBAIJ,&isSBAIJ);
21: if (!isSBAIJ) {
22: PetscObjectTypeCompare((PetscObject)mat,MATMPISBAIJ,&isSBAIJ);
23: }
24: if (isSBAIJ) SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_SUP,"Cannot convert from SBAIJ matrix since cannot obtain entire rows of matrix");
26: if (reuse == MAT_REUSE_MATRIX) {
27: M = *newmat;
28: } else {
29: PetscInt m,n,lm,ln;
30: MatGetSize(mat,&m,&n);
31: MatGetLocalSize(mat,&lm,&ln);
32: MatCreate(PetscObjectComm((PetscObject)mat),&M);
33: MatSetSizes(M,lm,ln,m,n);
34: MatSetBlockSizesFromMats(M,mat,mat);
35: MatSetType(M,newtype);
36: MatSeqDenseSetPreallocation(M,NULL);
37: MatMPIDenseSetPreallocation(M,NULL);
38: MatSetUp(M);
40: MatSetOption(M,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_FALSE);
41: MatSetOption(M,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);
42: PetscObjectTypeCompare((PetscObject)M,MATSEQSBAIJ,&isSBAIJ);
43: if (!isSBAIJ) {
44: PetscObjectTypeCompare((PetscObject)M,MATMPISBAIJ,&isSBAIJ);
45: }
46: if (isSBAIJ) {
47: MatSetOption(M,MAT_IGNORE_LOWER_TRIANGULAR,PETSC_TRUE);
48: }
49: }
51: MatGetOwnershipRange(mat,&rstart,&rend);
52: for (i=rstart; i<rend; i++) {
53: MatGetRow(mat,i,&nz,&cwork,&vwork);
54: MatSetValues(M,1,&i,nz,cwork,vwork,INSERT_VALUES);
55: MatRestoreRow(mat,i,&nz,&cwork,&vwork);
56: }
57: MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);
58: MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);
60: if (reuse == MAT_INPLACE_MATRIX) {
61: MatHeaderReplace(mat,&M);
62: } else {
63: *newmat = M;
64: }
65: return(0);
66: }