1c4762a1bSJed Brown static char help[] = "Reads in a binary file, extracts a submatrix from it, and writes to another binary file.\n\
2c4762a1bSJed Brown Options:\n\
3c4762a1bSJed Brown -fin <mat> : input matrix file\n\
4c4762a1bSJed Brown -fout <mat> : output marrix file\n\
5c4762a1bSJed Brown -start <row> : the row from where the submat should be extracted\n\
6c4762a1bSJed Brown -m <sx> : the size of the submatrix\n";
7c4762a1bSJed Brown
8c4762a1bSJed Brown #include <petscmat.h>
9c4762a1bSJed Brown #include <petscvec.h>
10c4762a1bSJed Brown
main(int argc,char ** args)11d71ae5a4SJacob Faibussowitsch int main(int argc, char **args)
12d71ae5a4SJacob Faibussowitsch {
13c4762a1bSJed Brown char fin[PETSC_MAX_PATH_LEN], fout[PETSC_MAX_PATH_LEN] = "default.mat";
14c4762a1bSJed Brown PetscViewer fdin, fdout;
15c4762a1bSJed Brown Vec b;
16c4762a1bSJed Brown MatType mtype = MATSEQBAIJ;
17c4762a1bSJed Brown Mat A, *B;
18c4762a1bSJed Brown PetscInt start = 0;
19c4762a1bSJed Brown PetscInt m;
20c4762a1bSJed Brown IS isrow, iscol;
21c4762a1bSJed Brown PetscBool flg;
22c4762a1bSJed Brown
23327415f7SBarry Smith PetscFunctionBeginUser;
24c8025a54SPierre Jolivet PetscCall(PetscInitialize(&argc, &args, NULL, help));
259566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetString(NULL, NULL, "-fin", fin, sizeof(fin), &flg));
2628b400f6SJacob Faibussowitsch PetscCheck(flg, PETSC_COMM_WORLD, PETSC_ERR_USER, "Must indicate binary file with the -fin option");
279566063dSJacob Faibussowitsch PetscCall(PetscViewerBinaryOpen(PETSC_COMM_SELF, fin, FILE_MODE_READ, &fdin));
28c4762a1bSJed Brown
299566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetString(NULL, NULL, "-fout", fout, sizeof(fout), &flg));
309566063dSJacob Faibussowitsch if (!flg) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Writing submatrix to file : %s\n", fout));
319566063dSJacob Faibussowitsch PetscCall(PetscViewerBinaryOpen(PETSC_COMM_SELF, fout, FILE_MODE_WRITE, &fdout));
32c4762a1bSJed Brown
339566063dSJacob Faibussowitsch PetscCall(MatCreate(PETSC_COMM_SELF, &A));
349566063dSJacob Faibussowitsch PetscCall(MatSetType(A, mtype));
359566063dSJacob Faibussowitsch PetscCall(MatLoad(A, fdin));
369566063dSJacob Faibussowitsch PetscCall(PetscViewerDestroy(&fdin));
37c4762a1bSJed Brown
389566063dSJacob Faibussowitsch PetscCall(MatGetSize(A, &m, &m));
39c4762a1bSJed Brown m /= 2;
409566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetInt(NULL, NULL, "-start", &start, NULL));
419566063dSJacob Faibussowitsch PetscCall(PetscOptionsGetInt(NULL, NULL, "-m", &m, NULL));
42c4762a1bSJed Brown
439566063dSJacob Faibussowitsch PetscCall(ISCreateStride(PETSC_COMM_SELF, m, start, 1, &isrow));
449566063dSJacob Faibussowitsch PetscCall(ISCreateStride(PETSC_COMM_SELF, m, start, 1, &iscol));
459566063dSJacob Faibussowitsch PetscCall(MatCreateSubMatrices(A, 1, &isrow, &iscol, MAT_INITIAL_MATRIX, &B));
469566063dSJacob Faibussowitsch PetscCall(MatView(B[0], fdout));
47c4762a1bSJed Brown
489566063dSJacob Faibussowitsch PetscCall(VecCreate(PETSC_COMM_SELF, &b));
499566063dSJacob Faibussowitsch PetscCall(VecSetSizes(b, PETSC_DECIDE, m));
509566063dSJacob Faibussowitsch PetscCall(VecSetFromOptions(b));
519566063dSJacob Faibussowitsch PetscCall(MatView(B[0], fdout));
529566063dSJacob Faibussowitsch PetscCall(PetscViewerDestroy(&fdout));
53c4762a1bSJed Brown
549566063dSJacob Faibussowitsch PetscCall(MatDestroy(&A));
559566063dSJacob Faibussowitsch PetscCall(MatDestroy(&B[0]));
569566063dSJacob Faibussowitsch PetscCall(VecDestroy(&b));
579566063dSJacob Faibussowitsch PetscCall(PetscFree(B));
589566063dSJacob Faibussowitsch PetscCall(ISDestroy(&iscol));
599566063dSJacob Faibussowitsch PetscCall(ISDestroy(&isrow));
609566063dSJacob Faibussowitsch PetscCall(PetscFinalize());
61b122ec5aSJacob Faibussowitsch return 0;
62c4762a1bSJed Brown }
63c4762a1bSJed Brown
64c4762a1bSJed Brown /*TEST
65c4762a1bSJed Brown
66c4762a1bSJed Brown test:
67c4762a1bSJed Brown args: -fin ${DATAFILESPATH}/matrices/small -fout joe -start 2 -m 4
68dfd57a17SPierre Jolivet requires: datafilespath double !complex !defined(PETSC_USE_64BIT_INDICES)
69*3886731fSPierre Jolivet output_file: output/empty.out
70c4762a1bSJed Brown
71c4762a1bSJed Brown TEST*/
72