Actual source code: spqmd.c
2: #include <petscmat.h>
3: #include <petsc/private/matorderimpl.h>
5: /*
6: MatGetOrdering_QMD - Find the Quotient Minimum Degree ordering of a given matrix.
7: */
8: PETSC_INTERN PetscErrorCode MatGetOrdering_QMD(Mat mat,MatOrderingType type,IS *row,IS *col)
9: {
10: PetscInt i, *deg,*marker,*rchset,*nbrhd,*qsize,*qlink,nofsub,*iperm,nrow,*perm;
11: const PetscInt *ia,*ja;
12: PetscBool done;
14: MatGetRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,&nrow,&ia,&ja,&done);
17: PetscMalloc1(nrow,&perm);
18: PetscMalloc5(nrow,&iperm,nrow,°,nrow,&marker,nrow,&rchset,nrow,&nbrhd);
19: PetscMalloc2(nrow,&qsize,nrow,&qlink);
20: /* WARNING - genqmd trashes ja */
21: SPARSEPACKgenqmd(&nrow,ia,ja,perm,iperm,deg,marker,rchset,nbrhd,qsize,qlink,&nofsub);
22: MatRestoreRowIJ(mat,1,PETSC_TRUE,PETSC_TRUE,NULL,&ia,&ja,&done);
24: PetscFree2(qsize,qlink);
25: PetscFree5(iperm,deg,marker,rchset,nbrhd);
26: for (i=0; i<nrow; i++) perm[i]--;
27: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_COPY_VALUES,row);
28: ISCreateGeneral(PETSC_COMM_SELF,nrow,perm,PETSC_OWN_POINTER,col);
29: return 0;
30: }