예제 #1
0
파일: zmpiaijf.c 프로젝트: Kun-Qu/petsc
EXTERN_C_BEGIN

void PETSC_STDCALL matmpiaijgetseqaij_(Mat *A,Mat *Ad,Mat *Ao,PetscInt *ic,size_t *iic,PetscErrorCode *ierr)
{
  PetscInt *i;
  *ierr = MatMPIAIJGetSeqAIJ(*A,Ad,Ao,&i);if (*ierr) return;
  *iic  = PetscIntAddressToFortran(ic,i);
}
예제 #2
0
/*
   PCGAMGCreateGraph - create simple scaled scalar graph from matrix

 Input Parameter:
 . Amat - matrix
 Output Parameter:
 . a_Gmaat - eoutput scalar graph (symmetric?)
 */
PetscErrorCode PCGAMGCreateGraph(Mat Amat, Mat *a_Gmat)
{
  PetscErrorCode ierr;
  PetscInt       Istart,Iend,Ii,jj,kk,ncols,nloc,NN,MM,bs;
  MPI_Comm       comm;
  Mat            Gmat;
  MatType        mtype;

  PetscFunctionBegin;
  ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
  ierr = MatGetOwnershipRange(Amat, &Istart, &Iend);CHKERRQ(ierr);
  ierr = MatGetSize(Amat, &MM, &NN);CHKERRQ(ierr);
  ierr = MatGetBlockSize(Amat, &bs);CHKERRQ(ierr);
  nloc = (Iend-Istart)/bs;

#if defined PETSC_GAMG_USE_LOG
  ierr = PetscLogEventBegin(petsc_gamg_setup_events[GRAPH],0,0,0,0);CHKERRQ(ierr);
#endif

  if (bs > 1) {
    const PetscScalar *vals;
    const PetscInt    *idx;
    PetscInt          *d_nnz, *o_nnz,*w0,*w1,*w2;
    PetscBool         ismpiaij,isseqaij;

    /*
       Determine the preallocation needed for the scalar matrix derived from the vector matrix.
    */

    ierr = PetscObjectBaseTypeCompare((PetscObject)Amat,MATSEQAIJ,&isseqaij);CHKERRQ(ierr);
    ierr = PetscObjectBaseTypeCompare((PetscObject)Amat,MATMPIAIJ,&ismpiaij);CHKERRQ(ierr);
    ierr = PetscMalloc2(nloc, &d_nnz,isseqaij ? 0 : nloc, &o_nnz);CHKERRQ(ierr);

    if (isseqaij) {
      PetscInt       max_d_nnz;

      /*
          Determine exact preallocation count for (sequential) scalar matrix
      */
      ierr = MatSeqAIJGetMaxRowNonzeros(Amat,&max_d_nnz);CHKERRQ(ierr);
      max_d_nnz = PetscMin(nloc,bs*max_d_nnz);CHKERRQ(ierr);
      ierr = PetscMalloc3(max_d_nnz, &w0,max_d_nnz, &w1,max_d_nnz, &w2);CHKERRQ(ierr);
      for (Ii = 0, jj = 0; Ii < Iend; Ii += bs, jj++) {
        ierr = MatCollapseRows(Amat,Ii,bs,w0,w1,w2,&d_nnz[jj],NULL);CHKERRQ(ierr);
      }
      ierr = PetscFree3(w0,w1,w2);CHKERRQ(ierr);

    } else if (ismpiaij) {
      Mat            Daij,Oaij;
      const PetscInt *garray;
      PetscInt       max_d_nnz;

      ierr = MatMPIAIJGetSeqAIJ(Amat,&Daij,&Oaij,&garray);CHKERRQ(ierr);

      /*
          Determine exact preallocation count for diagonal block portion of scalar matrix
      */
      ierr = MatSeqAIJGetMaxRowNonzeros(Daij,&max_d_nnz);CHKERRQ(ierr);
      max_d_nnz = PetscMin(nloc,bs*max_d_nnz);CHKERRQ(ierr);
      ierr = PetscMalloc3(max_d_nnz, &w0,max_d_nnz, &w1,max_d_nnz, &w2);CHKERRQ(ierr);
      for (Ii = 0, jj = 0; Ii < Iend - Istart; Ii += bs, jj++) {
        ierr = MatCollapseRows(Daij,Ii,bs,w0,w1,w2,&d_nnz[jj],NULL);CHKERRQ(ierr);
      }
      ierr = PetscFree3(w0,w1,w2);CHKERRQ(ierr);

      /*
         Over estimate (usually grossly over), preallocation count for off-diagonal portion of scalar matrix
      */
      for (Ii = 0, jj = 0; Ii < Iend - Istart; Ii += bs, jj++) {
        o_nnz[jj] = 0;
        for (kk=0; kk<bs; kk++) { /* rows that get collapsed to a single row */
          ierr = MatGetRow(Oaij,Ii+kk,&ncols,0,0);CHKERRQ(ierr);
          o_nnz[jj] += ncols;
          ierr = MatRestoreRow(Oaij,Ii+kk,&ncols,0,0);CHKERRQ(ierr);
        }
        if (o_nnz[jj] > (NN/bs-nloc)) o_nnz[jj] = NN/bs-nloc;
      }

    } else SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Require AIJ matrix type");

    /* get scalar copy (norms) of matrix */
    ierr = MatGetType(Amat,&mtype);CHKERRQ(ierr);
    ierr = MatCreate(comm, &Gmat);CHKERRQ(ierr);
    ierr = MatSetSizes(Gmat,nloc,nloc,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
    ierr = MatSetBlockSizes(Gmat, 1, 1);CHKERRQ(ierr);
    ierr = MatSetType(Gmat, mtype);CHKERRQ(ierr);
    ierr = MatSeqAIJSetPreallocation(Gmat,0,d_nnz);CHKERRQ(ierr);
    ierr = MatMPIAIJSetPreallocation(Gmat,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
    ierr = PetscFree2(d_nnz,o_nnz);CHKERRQ(ierr);

    for (Ii = Istart; Ii < Iend; Ii++) {
      PetscInt dest_row = Ii/bs;
      ierr = MatGetRow(Amat,Ii,&ncols,&idx,&vals);CHKERRQ(ierr);
      for (jj=0; jj<ncols; jj++) {
        PetscInt    dest_col = idx[jj]/bs;
        PetscScalar sv       = PetscAbs(PetscRealPart(vals[jj]));
        ierr = MatSetValues(Gmat,1,&dest_row,1,&dest_col,&sv,ADD_VALUES);CHKERRQ(ierr);
      }
      ierr = MatRestoreRow(Amat,Ii,&ncols,&idx,&vals);CHKERRQ(ierr);
    }
    ierr = MatAssemblyBegin(Gmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
    ierr = MatAssemblyEnd(Gmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
  } else {
    /* just copy scalar matrix - abs() not taken here but scaled later */
    ierr = MatDuplicate(Amat, MAT_COPY_VALUES, &Gmat);CHKERRQ(ierr);
  }

#if defined PETSC_GAMG_USE_LOG
  ierr = PetscLogEventEnd(petsc_gamg_setup_events[GRAPH],0,0,0,0);CHKERRQ(ierr);
#endif

  *a_Gmat = Gmat;
  PetscFunctionReturn(0);
}
예제 #3
0
/*
      Mm_ratio - ration of grid lines between fine and coarse grids.
*/
int main(int argc,char **argv)
{
  PetscErrorCode ierr;
  AppCtx         user;
  PetscInt       Npx=PETSC_DECIDE,Npy=PETSC_DECIDE,Npz=PETSC_DECIDE;
  PetscMPIInt    size,rank;
  PetscInt       m,n,M,N,i,nrows;
  PetscScalar    one = 1.0;
  PetscReal      fill=2.0;
  Mat            A,A_tmp,P,C,C1,C2;
  PetscScalar    *array,none = -1.0,alpha;
  Vec            x,v1,v2,v3,v4;
  PetscReal      norm,norm_tmp,norm_tmp1,tol=100.*PETSC_MACHINE_EPSILON;
  PetscRandom    rdm;
  PetscBool      Test_MatMatMult=PETSC_TRUE,Test_MatPtAP=PETSC_TRUE,Test_3D=PETSC_TRUE,flg;
  const PetscInt *ia,*ja;

  ierr = PetscInitialize(&argc,&argv,NULL,help);if (ierr) return ierr;
  ierr = PetscOptionsGetReal(NULL,NULL,"-tol",&tol,NULL);CHKERRQ(ierr);

  user.ratio     = 2;
  user.coarse.mx = 20; user.coarse.my = 20; user.coarse.mz = 20;

  ierr = PetscOptionsGetInt(NULL,NULL,"-Mx",&user.coarse.mx,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-My",&user.coarse.my,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-Mz",&user.coarse.mz,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-ratio",&user.ratio,NULL);CHKERRQ(ierr);

  if (user.coarse.mz) Test_3D = PETSC_TRUE;

  user.fine.mx = user.ratio*(user.coarse.mx-1)+1;
  user.fine.my = user.ratio*(user.coarse.my-1)+1;
  user.fine.mz = user.ratio*(user.coarse.mz-1)+1;

  ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
  ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-Npx",&Npx,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-Npy",&Npy,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-Npz",&Npz,NULL);CHKERRQ(ierr);

  /* Set up distributed array for fine grid */
  if (!Test_3D) {
    ierr = DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,user.fine.mx,user.fine.my,Npx,Npy,1,1,NULL,NULL,&user.fine.da);CHKERRQ(ierr);
  } else {
    ierr = DMDACreate3d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,user.fine.mx,user.fine.my,user.fine.mz,Npx,Npy,Npz,1,1,NULL,NULL,NULL,&user.fine.da);CHKERRQ(ierr);
  }
  ierr = DMSetFromOptions(user.fine.da);CHKERRQ(ierr);
  ierr = DMSetUp(user.fine.da);CHKERRQ(ierr);

  /* Test DMCreateMatrix()                                         */
  /*------------------------------------------------------------*/
  ierr = DMSetMatType(user.fine.da,MATAIJ);CHKERRQ(ierr);
  ierr = DMCreateMatrix(user.fine.da,&A);CHKERRQ(ierr);
  ierr = DMSetMatType(user.fine.da,MATBAIJ);CHKERRQ(ierr);
  ierr = DMCreateMatrix(user.fine.da,&C);CHKERRQ(ierr);

  ierr = MatConvert(C,MATAIJ,MAT_INITIAL_MATRIX,&A_tmp);CHKERRQ(ierr); /* not work for mpisbaij matrix! */
  ierr = MatEqual(A,A_tmp,&flg);CHKERRQ(ierr);
  if (!flg) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_NOTSAMETYPE,"A != C");
  ierr = MatDestroy(&C);CHKERRQ(ierr);
  ierr = MatDestroy(&A_tmp);CHKERRQ(ierr);

  /*------------------------------------------------------------*/

  ierr = MatGetLocalSize(A,&m,&n);CHKERRQ(ierr);
  ierr = MatGetSize(A,&M,&N);CHKERRQ(ierr);
  /* if (!rank) printf("A %d, %d\n",M,N); */

  /* set val=one to A */
  if (size == 1) {
    ierr = MatGetRowIJ(A,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = MatSeqAIJGetArray(A,&array);CHKERRQ(ierr);
      for (i=0; i<ia[nrows]; i++) array[i] = one;
      ierr = MatSeqAIJRestoreArray(A,&array);CHKERRQ(ierr);
    }
    ierr = MatRestoreRowIJ(A,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
  } else {
    Mat AA,AB;
    ierr = MatMPIAIJGetSeqAIJ(A,&AA,&AB,NULL);CHKERRQ(ierr);
    ierr = MatGetRowIJ(AA,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = MatSeqAIJGetArray(AA,&array);CHKERRQ(ierr);
      for (i=0; i<ia[nrows]; i++) array[i] = one;
      ierr = MatSeqAIJRestoreArray(AA,&array);CHKERRQ(ierr);
    }
    ierr = MatRestoreRowIJ(AA,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
    ierr = MatGetRowIJ(AB,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = MatSeqAIJGetArray(AB,&array);CHKERRQ(ierr);
      for (i=0; i<ia[nrows]; i++) array[i] = one;
      ierr = MatSeqAIJRestoreArray(AB,&array);CHKERRQ(ierr);
    }
    ierr = MatRestoreRowIJ(AB,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
  }
  /* ierr = MatView(A, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); */

  /* Set up distributed array for coarse grid */
  if (!Test_3D) {
    ierr = DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,user.coarse.mx,user.coarse.my,Npx,Npy,1,1,NULL,NULL,&user.coarse.da);CHKERRQ(ierr);
  } else {
    ierr = DMDACreate3d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,user.coarse.mx,user.coarse.my,user.coarse.mz,Npx,Npy,Npz,
                        1,1,NULL,NULL,NULL,&user.coarse.da);CHKERRQ(ierr);
  }
  ierr = DMSetFromOptions(user.coarse.da);CHKERRQ(ierr);
  ierr = DMSetUp(user.coarse.da);CHKERRQ(ierr);

  /* Create interpolation between the fine and coarse grids */
  ierr = DMCreateInterpolation(user.coarse.da,user.fine.da,&P,NULL);CHKERRQ(ierr);
  ierr = MatGetLocalSize(P,&m,&n);CHKERRQ(ierr);
  ierr = MatGetSize(P,&M,&N);CHKERRQ(ierr);
  /* if (!rank) printf("P %d, %d\n",M,N); */

  /* Create vectors v1 and v2 that are compatible with A */
  ierr = VecCreate(PETSC_COMM_WORLD,&v1);CHKERRQ(ierr);
  ierr = MatGetLocalSize(A,&m,NULL);CHKERRQ(ierr);
  ierr = VecSetSizes(v1,m,PETSC_DECIDE);CHKERRQ(ierr);
  ierr = VecSetFromOptions(v1);CHKERRQ(ierr);
  ierr = VecDuplicate(v1,&v2);CHKERRQ(ierr);
  ierr = PetscRandomCreate(PETSC_COMM_WORLD,&rdm);CHKERRQ(ierr);
  ierr = PetscRandomSetFromOptions(rdm);CHKERRQ(ierr);

  /* Test MatMatMult(): C = A*P */
  /*----------------------------*/
  if (Test_MatMatMult) {
    ierr = MatDuplicate(A,MAT_COPY_VALUES,&A_tmp);CHKERRQ(ierr);
    ierr = MatMatMult(A_tmp,P,MAT_INITIAL_MATRIX,fill,&C);CHKERRQ(ierr);

    /* Test MAT_REUSE_MATRIX - reuse symbolic C */
    alpha=1.0;
    for (i=0; i<2; i++) {
      alpha -= 0.1;
      ierr   = MatScale(A_tmp,alpha);CHKERRQ(ierr);
      ierr   = MatMatMult(A_tmp,P,MAT_REUSE_MATRIX,fill,&C);CHKERRQ(ierr);
    }
    /* Free intermediate data structures created for reuse of C=Pt*A*P */
    ierr = MatFreeIntermediateDataStructures(C);CHKERRQ(ierr);

    /* Test MatDuplicate()        */
    /*----------------------------*/
    ierr = MatDuplicate(C,MAT_COPY_VALUES,&C1);CHKERRQ(ierr);
    ierr = MatDuplicate(C1,MAT_COPY_VALUES,&C2);CHKERRQ(ierr);
    ierr = MatDestroy(&C1);CHKERRQ(ierr);
    ierr = MatDestroy(&C2);CHKERRQ(ierr);

    /* Create vector x that is compatible with P */
    ierr = VecCreate(PETSC_COMM_WORLD,&x);CHKERRQ(ierr);
    ierr = MatGetLocalSize(P,NULL,&n);CHKERRQ(ierr);
    ierr = VecSetSizes(x,n,PETSC_DECIDE);CHKERRQ(ierr);
    ierr = VecSetFromOptions(x);CHKERRQ(ierr);

    norm = 0.0;
    for (i=0; i<10; i++) {
      ierr      = VecSetRandom(x,rdm);CHKERRQ(ierr);
      ierr      = MatMult(P,x,v1);CHKERRQ(ierr);
      ierr      = MatMult(A_tmp,v1,v2);CHKERRQ(ierr); /* v2 = A*P*x */
      ierr      = MatMult(C,x,v1);CHKERRQ(ierr);  /* v1 = C*x   */
      ierr      = VecAXPY(v1,none,v2);CHKERRQ(ierr);
      ierr      = VecNorm(v1,NORM_1,&norm_tmp);CHKERRQ(ierr);
      ierr      = VecNorm(v2,NORM_1,&norm_tmp1);CHKERRQ(ierr);
      norm_tmp /= norm_tmp1;
      if (norm_tmp > norm) norm = norm_tmp;
    }
    if (norm >= tol && !rank) {
      ierr = PetscPrintf(PETSC_COMM_SELF,"Error: MatMatMult(), |v1 - v2|/|v2|: %g\n",(double)norm);CHKERRQ(ierr);
    }

    ierr = VecDestroy(&x);CHKERRQ(ierr);
    ierr = MatDestroy(&C);CHKERRQ(ierr);
    ierr = MatDestroy(&A_tmp);CHKERRQ(ierr);
  }

  /* Test P^T * A * P - MatPtAP() */
  /*------------------------------*/
  if (Test_MatPtAP) {
    ierr = MatPtAP(A,P,MAT_INITIAL_MATRIX,fill,&C);CHKERRQ(ierr);
    ierr = MatGetLocalSize(C,&m,&n);CHKERRQ(ierr);

    /* Test MAT_REUSE_MATRIX - reuse symbolic C */
    alpha=1.0;
    for (i=0; i<1; i++) {
      alpha -= 0.1;
      ierr   = MatScale(A,alpha);CHKERRQ(ierr);
      ierr   = MatPtAP(A,P,MAT_REUSE_MATRIX,fill,&C);CHKERRQ(ierr);
    }

    /* Free intermediate data structures created for reuse of C=Pt*A*P */
    ierr = MatFreeIntermediateDataStructures(C);CHKERRQ(ierr);

    /* Test MatDuplicate()        */
    /*----------------------------*/
    ierr = MatDuplicate(C,MAT_COPY_VALUES,&C1);CHKERRQ(ierr);
    ierr = MatDuplicate(C1,MAT_COPY_VALUES,&C2);CHKERRQ(ierr);
    ierr = MatDestroy(&C1);CHKERRQ(ierr);
    ierr = MatDestroy(&C2);CHKERRQ(ierr);

    /* Create vector x that is compatible with P */
    ierr = VecCreate(PETSC_COMM_WORLD,&x);CHKERRQ(ierr);
    ierr = MatGetLocalSize(P,&m,&n);CHKERRQ(ierr);
    ierr = VecSetSizes(x,n,PETSC_DECIDE);CHKERRQ(ierr);
    ierr = VecSetFromOptions(x);CHKERRQ(ierr);

    ierr = VecCreate(PETSC_COMM_WORLD,&v3);CHKERRQ(ierr);
    ierr = VecSetSizes(v3,n,PETSC_DECIDE);CHKERRQ(ierr);
    ierr = VecSetFromOptions(v3);CHKERRQ(ierr);
    ierr = VecDuplicate(v3,&v4);CHKERRQ(ierr);

    norm = 0.0;
    for (i=0; i<10; i++) {
      ierr = VecSetRandom(x,rdm);CHKERRQ(ierr);
      ierr = MatMult(P,x,v1);CHKERRQ(ierr);
      ierr = MatMult(A,v1,v2);CHKERRQ(ierr);  /* v2 = A*P*x */

      ierr = MatMultTranspose(P,v2,v3);CHKERRQ(ierr); /* v3 = Pt*A*P*x */
      ierr = MatMult(C,x,v4);CHKERRQ(ierr);           /* v3 = C*x   */
      ierr = VecAXPY(v4,none,v3);CHKERRQ(ierr);
      ierr = VecNorm(v4,NORM_1,&norm_tmp);CHKERRQ(ierr);
      ierr = VecNorm(v3,NORM_1,&norm_tmp1);CHKERRQ(ierr);

      norm_tmp /= norm_tmp1;
      if (norm_tmp > norm) norm = norm_tmp;
    }
    if (norm >= tol && !rank) {
      ierr = PetscPrintf(PETSC_COMM_SELF,"Error: MatPtAP(), |v3 - v4|/|v3|: %g\n",(double)norm);CHKERRQ(ierr);
    }
    ierr = MatDestroy(&C);CHKERRQ(ierr);
    ierr = VecDestroy(&v3);CHKERRQ(ierr);
    ierr = VecDestroy(&v4);CHKERRQ(ierr);
    ierr = VecDestroy(&x);CHKERRQ(ierr);
  }

  /* Clean up */
  ierr = MatDestroy(&A);CHKERRQ(ierr);
  ierr = PetscRandomDestroy(&rdm);CHKERRQ(ierr);
  ierr = VecDestroy(&v1);CHKERRQ(ierr);
  ierr = VecDestroy(&v2);CHKERRQ(ierr);
  ierr = DMDestroy(&user.fine.da);CHKERRQ(ierr);
  ierr = DMDestroy(&user.coarse.da);CHKERRQ(ierr);
  ierr = MatDestroy(&P);CHKERRQ(ierr);
  ierr = PetscFinalize();
  return ierr;
}
예제 #4
0
/*
      Mm_ratio - ration of grid lines between fine and coarse grids.
*/
int main(int argc,char **argv)
{
  PetscErrorCode ierr;
  AppCtx         user;
  PetscMPIInt    size,rank;
  PetscInt       m,n,M,N,i,nrows;
  PetscScalar    one = 1.0;
  PetscReal      fill=2.0;
  Mat            A,P,R,C,PtAP;
  PetscScalar    *array;
  PetscRandom    rdm;
  PetscBool      Test_3D=PETSC_FALSE,flg;
  const PetscInt *ia,*ja;

  ierr = PetscInitialize(&argc,&argv,NULL,help);if (ierr) return ierr;
  ierr = MPI_Comm_size(PETSC_COMM_WORLD,&size);CHKERRQ(ierr);
  ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRQ(ierr);

  /* Get size of fine grids and coarse grids */
  user.ratio     = 2;
  user.coarse.mx = 4; user.coarse.my = 4; user.coarse.mz = 4;

  ierr = PetscOptionsGetInt(NULL,NULL,"-Mx",&user.coarse.mx,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-My",&user.coarse.my,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-Mz",&user.coarse.mz,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-ratio",&user.ratio,NULL);CHKERRQ(ierr);
  if (user.coarse.mz) Test_3D = PETSC_TRUE;

  user.fine.mx = user.ratio*(user.coarse.mx-1)+1;
  user.fine.my = user.ratio*(user.coarse.my-1)+1;
  user.fine.mz = user.ratio*(user.coarse.mz-1)+1;

  if (!rank) {
    if (!Test_3D) {
      ierr = PetscPrintf(PETSC_COMM_SELF,"coarse grids: %D %D; fine grids: %D %D\n",user.coarse.mx,user.coarse.my,user.fine.mx,user.fine.my);CHKERRQ(ierr);
    } else {
      ierr = PetscPrintf(PETSC_COMM_SELF,"coarse grids: %D %D %D; fine grids: %D %D %D\n",user.coarse.mx,user.coarse.my,user.coarse.mz,user.fine.mx,user.fine.my,user.fine.mz);CHKERRQ(ierr);
    }
  }

  /* Set up distributed array for fine grid */
  if (!Test_3D) {
    ierr = DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,user.fine.mx,user.fine.my,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,&user.fine.da);CHKERRQ(ierr);
  } else {
    ierr = DMDACreate3d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,user.fine.mx,user.fine.my,user.fine.mz,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,
                        1,1,NULL,NULL,NULL,&user.fine.da);CHKERRQ(ierr);
  }
  ierr = DMSetFromOptions(user.fine.da);CHKERRQ(ierr);
  ierr = DMSetUp(user.fine.da);CHKERRQ(ierr);

  /* Create and set A at fine grids */
  ierr = DMSetMatType(user.fine.da,MATAIJ);CHKERRQ(ierr);
  ierr = DMCreateMatrix(user.fine.da,&A);CHKERRQ(ierr);
  ierr = MatGetLocalSize(A,&m,&n);CHKERRQ(ierr);
  ierr = MatGetSize(A,&M,&N);CHKERRQ(ierr);

  /* set val=one to A (replace with random values!) */
  ierr = PetscRandomCreate(PETSC_COMM_WORLD,&rdm);CHKERRQ(ierr);
  ierr = PetscRandomSetFromOptions(rdm);CHKERRQ(ierr);
  if (size == 1) {
    ierr = MatGetRowIJ(A,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = MatSeqAIJGetArray(A,&array);CHKERRQ(ierr);
      for (i=0; i<ia[nrows]; i++) array[i] = one;
      ierr = MatSeqAIJRestoreArray(A,&array);CHKERRQ(ierr);
    }
    ierr = MatRestoreRowIJ(A,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
  } else {
    Mat AA,AB;
    ierr = MatMPIAIJGetSeqAIJ(A,&AA,&AB,NULL);CHKERRQ(ierr);
    ierr = MatGetRowIJ(AA,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = MatSeqAIJGetArray(AA,&array);CHKERRQ(ierr);
      for (i=0; i<ia[nrows]; i++) array[i] = one;
      ierr = MatSeqAIJRestoreArray(AA,&array);CHKERRQ(ierr);
    }
    ierr = MatRestoreRowIJ(AA,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
    ierr = MatGetRowIJ(AB,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
    if (flg) {
      ierr = MatSeqAIJGetArray(AB,&array);CHKERRQ(ierr);
      for (i=0; i<ia[nrows]; i++) array[i] = one;
      ierr = MatSeqAIJRestoreArray(AB,&array);CHKERRQ(ierr);
    }
    ierr = MatRestoreRowIJ(AB,0,PETSC_FALSE,PETSC_FALSE,&nrows,&ia,&ja,&flg);CHKERRQ(ierr);
  }
  /* Set up distributed array for coarse grid */
  if (!Test_3D) {
    ierr = DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,user.coarse.mx,user.coarse.my,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,&user.coarse.da);CHKERRQ(ierr);
  } else {
    ierr = DMDACreate3d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,user.coarse.mx,user.coarse.my,user.coarse.mz,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,NULL,&user.coarse.da);CHKERRQ(ierr);
  }
  ierr = DMSetFromOptions(user.coarse.da);CHKERRQ(ierr);
  ierr = DMSetUp(user.coarse.da);CHKERRQ(ierr);

  /* Create interpolation between the fine and coarse grids */
  ierr = DMCreateInterpolation(user.coarse.da,user.fine.da,&P,NULL);CHKERRQ(ierr);

  /* Get R = P^T */
  ierr = MatTranspose(P,MAT_INITIAL_MATRIX,&R);CHKERRQ(ierr);

  /* C = R*A*P */
  ierr = MatMatMatMult(R,A,P,MAT_INITIAL_MATRIX,fill,&C);CHKERRQ(ierr);
  ierr = MatMatMatMult(R,A,P,MAT_REUSE_MATRIX,fill,&C);CHKERRQ(ierr);

  /* Test C == PtAP */
  ierr = MatPtAP(A,P,MAT_INITIAL_MATRIX,fill,&PtAP);CHKERRQ(ierr);
  ierr = MatPtAP(A,P,MAT_REUSE_MATRIX,fill,&PtAP);CHKERRQ(ierr);
  ierr = MatEqual(C,PtAP,&flg);CHKERRQ(ierr);
  if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_PLIB,"Matrices are not equal");
  ierr = MatDestroy(&PtAP);CHKERRQ(ierr);

  /* Clean up */
  ierr = MatDestroy(&A);CHKERRQ(ierr);
  ierr = PetscRandomDestroy(&rdm);CHKERRQ(ierr);
  ierr = DMDestroy(&user.fine.da);CHKERRQ(ierr);
  ierr = DMDestroy(&user.coarse.da);CHKERRQ(ierr);
  ierr = MatDestroy(&P);CHKERRQ(ierr);
  ierr = MatDestroy(&R);CHKERRQ(ierr);
  ierr = MatDestroy(&C);CHKERRQ(ierr);
  ierr = PetscFinalize();
  return ierr;
}