Actual source code: spnd.c
1: #define PETSCMAT_DLL
3: #include petscmat.h
4: #include ../src/mat/order/order.h
7: /*
8: MatOrdering_ND - Find the nested dissection ordering of a given matrix.
9: */
12: PetscErrorCode MatOrdering_ND(Mat mat,const MatOrderingType type,IS *row,IS *col)
13: {
15: PetscInt i, *mask,*xls,*ls,nrow,*ia,*ja,*perm;
16: PetscTruth done;
19: MatGetRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);
20: if (!done) SETERRQ1(PETSC_ERR_SUP,"Cannot get rows for matrix type %s",((PetscObject)mat)->type_name);
22: PetscMalloc4(nrow,PetscInt,&mask,nrow,PetscInt,&perm,nrow+1,PetscInt,&xls,nrow,PetscInt,&ls);
23: SPARSEPACKgennd(&nrow,ia,ja,mask,perm,xls,ls);
24: MatRestoreRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);
26: /* shift because Sparsepack indices start at one */
27: for (i=0; i<nrow; i++) perm[i]--;
29: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,row);
30: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,col);
31: PetscFree4(mask,perm,xls,ls);
32: return(0);
33: }