Actual source code: sprcm.c
1: /*$Id: sprcm.c,v 1.40 2001/03/23 23:22:51 balay Exp $*/
3: #include petscmat.h
4: #include src/mat/order/order.h
6: EXTERN_C_BEGIN
7: /*
8: MatOrdering_RCM - Find the Reverse Cuthill-McKee ordering of a given matrix.
9: */
12: int MatOrdering_RCM(Mat mat,const MatOrderingType type,IS *row,IS *col)
13: {
14: int ierr,i, *mask,*xls,nrow,*ia,*ja,*perm;
15: PetscTruth done;
18: MatGetRowIJ(mat,1,PETSC_TRUE,&nrow,&ia,&ja,&done);
19: if (!done) SETERRQ(PETSC_ERR_SUP,"Cannot get rows for matrix");
21: PetscMalloc(4*nrow * sizeof(int),&mask);
22: perm = mask + nrow;
23: xls = perm + nrow;
25: SPARSEPACKgenrcm(&nrow,ia,ja,perm,mask,xls);
26: MatRestoreRowIJ(mat,1,PETSC_TRUE,&nrow,&ia,&ja,&done);
28: /* shift because Sparsepack indices start at one */
29: for (i=0; i<nrow; i++) perm[i]--;
31: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,row);
32: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,col);
33: PetscFree(mask);
35: return(0);
36: }
37: EXTERN_C_END