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,&deg,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: }