Actual source code: sprcm.c

      1: #define PETSCMAT_DLL

     3:  #include petscmat.h
     4:  #include src/mat/order/order.h

      7: /*
      8:     MatOrdering_RCM - Find the Reverse Cuthill-McKee ordering of a given matrix.
      9: */
     12: PetscErrorCode PETSCMAT_DLLEXPORT MatOrdering_RCM(Mat mat,const MatOrderingType type,IS *row,IS *col)
     13: {
     15:   PetscInt       i,*mask,*xls,nrow,*ia,*ja,*perm;
     16:   PetscTruth     done;

     19:   MatGetRowIJ(mat,1,PETSC_TRUE,&nrow,&ia,&ja,&done);
     20:   if (!done) SETERRQ(PETSC_ERR_SUP,"Cannot get rows for matrix");

     22:   PetscMalloc(4*nrow * sizeof(PetscInt),&mask);
     23:   perm = mask + nrow;
     24:   xls  = perm + nrow;

     26:   SPARSEPACKgenrcm(&nrow,ia,ja,perm,mask,xls);
     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: }