Actual source code: sprcm.c
2: #include <petscmat.h>
3: #include <petsc/private/matorderimpl.h>
5: /*
6: MatGetOrdering_RCM - Find the Reverse Cuthill-McKee ordering of a given matrix.
7: */
8: PETSC_INTERN PetscErrorCode MatGetOrdering_RCM(Mat mat,MatOrderingType type,IS *row,IS *col)
9: {
10: PetscInt i,*mask,*xls,nrow,*perm;
11: const PetscInt *ia,*ja;
12: PetscBool done;
14: MatGetRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);
17: PetscMalloc3(nrow,&mask,nrow,&perm,2*nrow,&xls);
18: SPARSEPACKgenrcm(&nrow,ia,ja,perm,mask,xls);
19: MatRestoreRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,NULL,&ia,&ja,&done);
21: /* shift because Sparsepack indices start at one */
22: for (i=0; i<nrow; i++) perm[i]--;
23: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_COPY_VALUES,row);
24: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_COPY_VALUES,col);
25: PetscFree3(mask,perm,xls);
26: return 0;
27: }