Actual source code: spqmd.c
1: #define PETSCMAT_DLL
3: #include petscmat.h
4: #include src/mat/order/order.h
7: /*
8: MatOrdering_QMD - Find the Quotient Minimum Degree ordering of a given matrix.
9: */
12: PetscErrorCode MatOrdering_QMD(Mat mat,const MatOrderingType type,IS *row,IS *col)
13: {
14: PetscInt i, *deg,*marker,*rchset,*nbrhd,*qsize,*qlink,nofsub,*iperm,nrow;
16: PetscInt *ia,*ja,*perm;
17: PetscTruth done;
20: MatGetRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);
21: if (!done) SETERRQ(PETSC_ERR_SUP,"Cannot get rows for matrix");
23: PetscMalloc(nrow * sizeof(PetscInt),&perm);
24: PetscMalloc(nrow * sizeof(PetscInt),&iperm);
25: PetscMalloc(nrow * sizeof(PetscInt),°);
26: PetscMalloc(nrow * sizeof(PetscInt),&marker);
27: PetscMalloc(nrow * sizeof(PetscInt),&rchset);
28: PetscMalloc(nrow * sizeof(PetscInt),&nbrhd);
29: PetscMalloc(nrow * sizeof(PetscInt),&qsize);
30: PetscMalloc(nrow * sizeof(PetscInt),&qlink);
31: /* WARNING - genqmd trashes ja */
32: SPARSEPACKgenqmd(&nrow,ia,ja,perm,iperm,deg,marker,rchset,nbrhd,qsize,qlink,&nofsub);
33: MatRestoreRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);
35: PetscFree(deg);
36: PetscFree(marker);
37: PetscFree(rchset);
38: PetscFree(nbrhd);
39: PetscFree(qsize);
40: PetscFree(qlink);
41: PetscFree(iperm);
42: for (i=0; i<nrow; i++) perm[i]--;
43: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,row);
44: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,col);
45: PetscFree(perm);
46: return(0);
47: }