2: static char help[] = "Tests MatReorderForNonzeroDiagonal().\n\n";

  4: #include <petscmat.h>

  8: int main(int argc,char **argv)
  9: {
 10:   Mat            mat,B;
 12:   PetscInt       i,j;
 13:   PetscScalar    v;
 14:   IS             isrow,iscol;
 15:   PetscViewer    viewer;

 17:   PetscInitialize(&argc,&argv,(char*)0,help);


 20:   /* ------- Assemble matrix, --------- */

 22:   MatCreate(PETSC_COMM_WORLD,&mat);
 23:   MatSetSizes(mat,PETSC_DECIDE,PETSC_DECIDE,4,4);
 24:   MatSetFromOptions(mat);
 25:   MatSetUp(mat);

 27:   /* set anti-diagonal of matrix */
 28:   v    = 1.0;
 29:   i    = 0; j = 3;
 30:   MatSetValues(mat,1,&i,1,&j,&v,INSERT_VALUES);
 31:   v    = 2.0;
 32:   i    = 1; j = 2;
 33:   MatSetValues(mat,1,&i,1,&j,&v,INSERT_VALUES);
 34:   v    = 3.0;
 35:   i    = 2; j = 1;
 36:   MatSetValues(mat,1,&i,1,&j,&v,INSERT_VALUES);
 37:   v    = 4.0;
 38:   i    = 3; j = 0;
 39:   MatSetValues(mat,1,&i,1,&j,&v,INSERT_VALUES);

 41:   MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);
 42:   MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);

 44:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 45:   PetscViewerSetFormat(viewer,PETSC_VIEWER_ASCII_DENSE);
 46:   PetscViewerASCIIPrintf(viewer,"Original matrix\n");
 47:   MatView(mat,viewer);

 49:   MatGetOrdering(mat,MATORDERINGNATURAL,&isrow,&iscol);

 51:   MatPermute(mat,isrow,iscol,&B);
 52:   PetscViewerASCIIPrintf(viewer,"Original matrix permuted by identity\n");
 53:   MatView(B,viewer);
 54:   MatDestroy(&B);

 56:   MatReorderForNonzeroDiagonal(mat,1.e-8,isrow,iscol);
 57:   MatPermute(mat,isrow,iscol,&B);
 58:   PetscViewerASCIIPrintf(viewer,"Original matrix permuted by identity + NonzeroDiagonal()\n");
 59:   MatView(B,viewer);
 60:   PetscViewerASCIIPrintf(viewer,"Row permutation\n");
 61:   ISView(isrow,viewer);
 62:   PetscViewerASCIIPrintf(viewer,"Column permutation\n");
 63:   ISView(iscol,viewer);
 64:   MatDestroy(&B);

 66:   ISDestroy(&isrow);
 67:   ISDestroy(&iscol);

 69:   MatGetOrdering(mat,MATORDERINGND,&isrow,&iscol);
 70:   MatPermute(mat,isrow,iscol,&B);
 71:   PetscViewerASCIIPrintf(viewer,"Original matrix permuted by ND\n");
 72:   MatView(B,viewer);
 73:   MatDestroy(&B);
 74:   PetscViewerASCIIPrintf(viewer,"ND row permutation\n");
 75:   ISView(isrow,viewer);
 76:   PetscViewerASCIIPrintf(viewer,"ND column permutation\n");
 77:   ISView(iscol,viewer);

 79:   MatReorderForNonzeroDiagonal(mat,1.e-8,isrow,iscol);
 80:   MatPermute(mat,isrow,iscol,&B);
 81:   PetscViewerASCIIPrintf(viewer,"Original matrix permuted by ND + NonzeroDiagonal()\n");
 82:   MatView(B,viewer);
 83:   MatDestroy(&B);
 84:   PetscViewerASCIIPrintf(viewer,"ND + NonzeroDiagonal() row permutation\n");
 85:   ISView(isrow,viewer);
 86:   PetscViewerASCIIPrintf(viewer,"ND + NonzeroDiagonal() column permutation\n");
 87:   ISView(iscol,viewer);

 89:   ISDestroy(&isrow);
 90:   ISDestroy(&iscol);

 92:   MatGetOrdering(mat,MATORDERINGRCM,&isrow,&iscol);
 93:   MatPermute(mat,isrow,iscol,&B);
 94:   PetscViewerASCIIPrintf(viewer,"Original matrix permuted by RCM\n");
 95:   MatView(B,viewer);
 96:   MatDestroy(&B);
 97:   PetscViewerASCIIPrintf(viewer,"RCM row permutation\n");
 98:   ISView(isrow,viewer);
 99:   PetscViewerASCIIPrintf(viewer,"RCM column permutation\n");
100:   ISView(iscol,viewer);

102:   MatReorderForNonzeroDiagonal(mat,1.e-8,isrow,iscol);
103:   MatPermute(mat,isrow,iscol,&B);
104:   PetscViewerASCIIPrintf(viewer,"Original matrix permuted by RCM + NonzeroDiagonal()\n");
105:   MatView(B,viewer);
106:   MatDestroy(&B);
107:   PetscViewerASCIIPrintf(viewer,"RCM + NonzeroDiagonal() row permutation\n");
108:   ISView(isrow,viewer);
109:   PetscViewerASCIIPrintf(viewer,"RCM + NonzeroDiagonal() column permutation\n");
110:   ISView(iscol,viewer);

112:   MatLUFactor(mat,isrow,iscol,NULL);
113:   PetscViewerASCIIPrintf(viewer,"Factored matrix permuted by RCM + NonzeroDiagonal()\n");
114:   MatView(mat,viewer);

116:   /* Free data structures */
117:   ISDestroy(&isrow);
118:   ISDestroy(&iscol);
119:   MatDestroy(&mat);

121:   PetscFinalize();
122:   return 0;
123: }