Actual source code: spnd.c
1: /*$Id: spnd.c,v 1.41 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_ND - Find the nested dissection ordering of a given matrix.
9: */
12: int MatOrdering_ND(Mat mat,const MatOrderingType type,IS *row,IS *col)
13: {
14: int ierr,i, *mask,*xls,*ls,nrow,*ia,*ja,*perm;
15: PetscTruth done;
18: MatGetRowIJ(mat,1,PETSC_TRUE,&nrow,&ia,&ja,&done);
19: if (!done) SETERRQ1(PETSC_ERR_SUP,"Cannot get rows for matrix type %s",((PetscObject)mat)->type_name);
21: PetscMalloc((4*nrow +1) * sizeof(int),&mask);
22: perm = mask + nrow;
23: xls = perm + nrow;
24: ls = xls + nrow + 1;
26: SPARSEPACKgennd(&nrow,ia,ja,mask,perm,xls,ls);
27: MatRestoreRowIJ(mat,1,PETSC_TRUE,&nrow,&ia,&ja,&done);
29: /* shift because Sparsepack indices start at one */
30: for (i=0; i<nrow; i++) perm[i]--;
32: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,row);
33: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,col);
34: PetscFree(mask);
36: return(0);
37: }
38: EXTERN_C_END