Exemple #1
0
int main(int argc,char **argv)
{
  KSP            ksp;
  DM             da;
  PetscReal      norm;
  PetscErrorCode ierr;

  PetscInt    i,j,k,mx,my,mz,xm,ym,zm,xs,ys,zs;
  PetscScalar Hx,Hy,Hz;
  PetscScalar ***array;
  Vec         x,b,r;
  Mat         J;

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

  ierr = KSPCreate(PETSC_COMM_WORLD,&ksp);CHKERRQ(ierr);
  ierr = DMDACreate3d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,-12,-12,-12,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,1,1,0,0,0,&da);CHKERRQ(ierr);
  ierr = DMDASetInterpolationType(da, DMDA_Q0);CHKERRQ(ierr);

  ierr = KSPSetDM(ksp,da);CHKERRQ(ierr);

  ierr = KSPSetComputeRHS(ksp,ComputeRHS,NULL);CHKERRQ(ierr);
  ierr = KSPSetComputeOperators(ksp,ComputeMatrix,NULL);CHKERRQ(ierr);
  ierr = KSPSetFromOptions(ksp);CHKERRQ(ierr);
  ierr = KSPSolve(ksp,NULL,NULL);CHKERRQ(ierr);
  ierr = KSPGetSolution(ksp,&x);CHKERRQ(ierr);
  ierr = KSPGetRhs(ksp,&b);CHKERRQ(ierr);
  ierr = KSPGetOperators(ksp,NULL,&J);CHKERRQ(ierr);
  ierr = VecDuplicate(b,&r);CHKERRQ(ierr);

  ierr = MatMult(J,x,r);CHKERRQ(ierr);
  ierr = VecAXPY(r,-1.0,b);CHKERRQ(ierr);
  ierr = VecNorm(r,NORM_2,&norm);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Residual norm %g\n",(double)norm);CHKERRQ(ierr);

  ierr = DMDAGetInfo(da, 0, &mx, &my, &mz, 0,0,0,0,0,0,0,0,0);CHKERRQ(ierr);
  Hx   = 1.0 / (PetscReal)(mx);
  Hy   = 1.0 / (PetscReal)(my);
  Hz   = 1.0 / (PetscReal)(mz);
  ierr = DMDAGetCorners(da,&xs,&ys,&zs,&xm,&ym,&zm);CHKERRQ(ierr);
  ierr = DMDAVecGetArray(da, x, &array);CHKERRQ(ierr);

  for (k=zs; k<zs+zm; k++) {
    for (j=ys; j<ys+ym; j++) {
      for (i=xs; i<xs+xm; i++) {
        array[k][j][i] -=
          PetscCosScalar(2*PETSC_PI*(((PetscReal)i+0.5)*Hx))*
          PetscCosScalar(2*PETSC_PI*(((PetscReal)j+0.5)*Hy))*
          PetscCosScalar(2*PETSC_PI*(((PetscReal)k+0.5)*Hz));
      }
    }
  }
  ierr = DMDAVecRestoreArray(da, x, &array);CHKERRQ(ierr);
  ierr = VecAssemblyBegin(x);CHKERRQ(ierr);
  ierr = VecAssemblyEnd(x);CHKERRQ(ierr);

  ierr = VecNorm(x,NORM_INFINITY,&norm);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Error norm %g\n",(double)norm);CHKERRQ(ierr);
  ierr = VecNorm(x,NORM_1,&norm);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Error norm %g\n",(double)(norm/((PetscReal)(mx)*(PetscReal)(my)*(PetscReal)(mz))));CHKERRQ(ierr);
  ierr = VecNorm(x,NORM_2,&norm);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Error norm %g\n",(double)(norm/((PetscReal)(mx)*(PetscReal)(my)*(PetscReal)(mz))));CHKERRQ(ierr);

  ierr = VecDestroy(&r);CHKERRQ(ierr);
  ierr = KSPDestroy(&ksp);CHKERRQ(ierr);
  ierr = DMDestroy(&da);CHKERRQ(ierr);
  ierr = PetscFinalize();
  return 0;
}
Exemple #2
0
int main(int argc,char **argv)
{
  PetscErrorCode ierr;
  KSP            ksp;
  PC             pc;
  Vec            x,b;
  DM             da;
  Mat            A,Atrans;
  PetscInt       dof=1,M=8;
  PetscBool      flg,trans=PETSC_FALSE;

  ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
  ierr = PetscOptionsGetInt(NULL,NULL,"-dof",&dof,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(NULL,NULL,"-M",&M,NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetBool(NULL,NULL,"-trans",&trans,NULL);CHKERRQ(ierr);

  ierr = DMDACreate(PETSC_COMM_WORLD,&da);CHKERRQ(ierr);
  ierr = DMSetDimension(da,3);CHKERRQ(ierr);
  ierr = DMDASetBoundaryType(da,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE);CHKERRQ(ierr);
  ierr = DMDASetStencilType(da,DMDA_STENCIL_STAR);CHKERRQ(ierr);
  ierr = DMDASetSizes(da,M,M,M);CHKERRQ(ierr);
  ierr = DMDASetNumProcs(da,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE);CHKERRQ(ierr);
  ierr = DMDASetDof(da,dof);CHKERRQ(ierr);
  ierr = DMDASetStencilWidth(da,1);CHKERRQ(ierr);
  ierr = DMDASetOwnershipRanges(da,NULL,NULL,NULL);CHKERRQ(ierr);
  ierr = DMSetFromOptions(da);CHKERRQ(ierr);
  ierr = DMSetUp(da);CHKERRQ(ierr);

  ierr = DMCreateGlobalVector(da,&x);CHKERRQ(ierr);
  ierr = DMCreateGlobalVector(da,&b);CHKERRQ(ierr);
  ierr = ComputeRHS(da,b);CHKERRQ(ierr);
  ierr = DMSetMatType(da,MATBAIJ);CHKERRQ(ierr);
  ierr = DMSetFromOptions(da);CHKERRQ(ierr);
  ierr = DMCreateMatrix(da,&A);CHKERRQ(ierr);
  ierr = ComputeMatrix(da,A);CHKERRQ(ierr);

  /* A is non-symmetric. Make A = 0.5*(A + Atrans) symmetric for testing icc and cholesky */
  ierr = MatTranspose(A,MAT_INITIAL_MATRIX,&Atrans);CHKERRQ(ierr);
  ierr = MatAXPY(A,1.0,Atrans,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);
  ierr = MatScale(A,0.5);CHKERRQ(ierr);
  ierr = MatDestroy(&Atrans);CHKERRQ(ierr);

  /* Test sbaij matrix */
  flg  = PETSC_FALSE;
  ierr = PetscOptionsGetBool(NULL,NULL, "-test_sbaij1", &flg,NULL);CHKERRQ(ierr);
  if (flg) {
    Mat       sA;
    PetscBool issymm;
    ierr = MatIsTranspose(A,A,0.0,&issymm);CHKERRQ(ierr);
    if (issymm) {
      ierr = MatSetOption(A,MAT_SYMMETRIC,PETSC_TRUE);CHKERRQ(ierr);
    } else {ierr = PetscPrintf(PETSC_COMM_WORLD,"Warning: A is non-symmetric\n");CHKERRQ(ierr);}
    ierr = MatConvert(A,MATSBAIJ,MAT_INITIAL_MATRIX,&sA);CHKERRQ(ierr);
    ierr = MatDestroy(&A);CHKERRQ(ierr);
    A    = sA;
  }

  ierr = KSPCreate(PETSC_COMM_WORLD,&ksp);CHKERRQ(ierr);
  ierr = KSPSetFromOptions(ksp);CHKERRQ(ierr);
  ierr = KSPSetOperators(ksp,A,A);CHKERRQ(ierr);
  ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr);
  ierr = PCSetDM(pc,(DM)da);CHKERRQ(ierr);

  if (trans) {
    ierr = KSPSolveTranspose(ksp,b,x);CHKERRQ(ierr);
  } else {
    ierr = KSPSolve(ksp,b,x);CHKERRQ(ierr);
  }

  /* check final residual */
  flg  = PETSC_FALSE;
  ierr = PetscOptionsGetBool(NULL,NULL, "-check_final_residual", &flg,NULL);CHKERRQ(ierr);
  if (flg) {
    Vec       b1;
    PetscReal norm;
    ierr = KSPGetSolution(ksp,&x);CHKERRQ(ierr);
    ierr = VecDuplicate(b,&b1);CHKERRQ(ierr);
    ierr = MatMult(A,x,b1);CHKERRQ(ierr);
    ierr = VecAXPY(b1,-1.0,b);CHKERRQ(ierr);
    ierr = VecNorm(b1,NORM_2,&norm);CHKERRQ(ierr);
    ierr = PetscPrintf(PETSC_COMM_WORLD,"Final residual %g\n",norm);CHKERRQ(ierr);
    ierr = VecDestroy(&b1);CHKERRQ(ierr);
  }

  ierr = KSPDestroy(&ksp);CHKERRQ(ierr);
  ierr = VecDestroy(&x);CHKERRQ(ierr);
  ierr = VecDestroy(&b);CHKERRQ(ierr);
  ierr = MatDestroy(&A);CHKERRQ(ierr);
  ierr = DMDestroy(&da);CHKERRQ(ierr);
  ierr = PetscFinalize();
  return ierr;
}
Exemple #3
0
int main(int argc,char **argv)
{
  PetscErrorCode ierr;
  KSP            ksp;
  PC             pc;
  Vec            x,b;
  DA             da;
  Mat            A,Atrans;
  PetscInt       dof=1,M=-8;
  PetscTruth     flg,trans=PETSC_FALSE;

  PetscInitialize(&argc,&argv,(char *)0,help);
  ierr = PetscOptionsGetInt(PETSC_NULL,"-dof",&dof,PETSC_NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetInt(PETSC_NULL,"-M",&M,PETSC_NULL);CHKERRQ(ierr);
  ierr = PetscOptionsGetTruth(PETSC_NULL,"-trans",&trans,PETSC_NULL);CHKERRQ(ierr);

  ierr = DACreate(PETSC_COMM_WORLD,&da);CHKERRQ(ierr);
  ierr = DASetDim(da,3);CHKERRQ(ierr);
  ierr = DASetPeriodicity(da,DA_NONPERIODIC);CHKERRQ(ierr);
  ierr = DASetStencilType(da,DA_STENCIL_STAR);CHKERRQ(ierr);
  ierr = DASetSizes(da,M,M,M);CHKERRQ(ierr);
  ierr = DASetNumProcs(da,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE);CHKERRQ(ierr);
  ierr = DASetDof(da,dof);CHKERRQ(ierr);
  ierr = DASetStencilWidth(da,1);CHKERRQ(ierr);
  ierr = DASetVertexDivision(da,PETSC_NULL,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
  ierr = DASetFromOptions(da);CHKERRQ(ierr);

  ierr = DACreateGlobalVector(da,&x);CHKERRQ(ierr);
  ierr = DACreateGlobalVector(da,&b);CHKERRQ(ierr);
  ierr = ComputeRHS(da,b);CHKERRQ(ierr);
  ierr = DAGetMatrix(da,MATBAIJ,&A);CHKERRQ(ierr);
  ierr = ComputeMatrix(da,A);CHKERRQ(ierr);


  /* A is non-symmetric. Make A = 0.5*(A + Atrans) symmetric for testing icc and cholesky */
  ierr = MatTranspose(A,MAT_INITIAL_MATRIX,&Atrans);CHKERRQ(ierr);
  ierr = MatAXPY(A,1.0,Atrans,DIFFERENT_NONZERO_PATTERN);CHKERRQ(ierr);
  ierr = MatScale(A,0.5);CHKERRQ(ierr);
  ierr = MatDestroy(Atrans);CHKERRQ(ierr);

  /* Test sbaij matrix */
  flg  = PETSC_FALSE;
  ierr = PetscOptionsGetTruth(PETSC_NULL, "-test_sbaij1", &flg,PETSC_NULL);CHKERRQ(ierr);
  if (flg){
    Mat sA;
    ierr = MatConvert(A,MATSBAIJ,MAT_INITIAL_MATRIX,&sA);CHKERRQ(ierr);
    ierr = MatDestroy(A);CHKERRQ(ierr);
    A = sA;
  }

  ierr = KSPCreate(PETSC_COMM_WORLD,&ksp);CHKERRQ(ierr);
  ierr = KSPSetFromOptions(ksp);CHKERRQ(ierr);
  ierr = KSPSetOperators(ksp,A,A,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
  ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr);
  ierr = PCSetDA(pc,da);CHKERRQ(ierr);
 
  if (trans) {
    ierr = KSPSolveTranspose(ksp,b,x);CHKERRQ(ierr);
  } else {
    ierr = KSPSolve(ksp,b,x);CHKERRQ(ierr);
  }

  /* check final residual */
  flg  = PETSC_FALSE;
  ierr = PetscOptionsGetTruth(PETSC_NULL, "-check_final_residual", &flg,PETSC_NULL);CHKERRQ(ierr);
  if (flg){
    Vec            b1;
    PetscReal      norm;
    ierr = KSPGetSolution(ksp,&x);CHKERRQ(ierr);
    ierr = VecDuplicate(b,&b1);CHKERRQ(ierr);
    ierr = MatMult(A,x,b1);CHKERRQ(ierr);
    ierr = VecAXPY(b1,-1.0,b);CHKERRQ(ierr);
    ierr = VecNorm(b1,NORM_2,&norm);CHKERRQ(ierr);
    ierr = PetscPrintf(PETSC_COMM_WORLD,"Final residual %g\n",norm);CHKERRQ(ierr);
    ierr = VecDestroy(b1);CHKERRQ(ierr);
  }
   
  ierr = KSPDestroy(ksp);CHKERRQ(ierr);
  ierr = VecDestroy(x);CHKERRQ(ierr);
  ierr = VecDestroy(b);CHKERRQ(ierr);
  ierr = MatDestroy(A);CHKERRQ(ierr);
  ierr = DADestroy(da);CHKERRQ(ierr);
  ierr = PetscFinalize();CHKERRQ(ierr);
  return 0;
}
int main(int argc,char **argv)
{
  PetscErrorCode ierr;
  KSP            ksp;
  PC             pc;
  Vec            x,b;
  DM             da;
  Mat            A;
  PetscInt       dof=1;
  PetscBool      flg;
  PetscScalar    zero=0.0;

  PetscInitialize(&argc,&argv,(char*)0,help);
  ierr = PetscOptionsGetInt(NULL,"-dof",&dof,NULL);CHKERRQ(ierr);

  ierr = DMDACreate(PETSC_COMM_WORLD,&da);CHKERRQ(ierr);
  ierr = DMDASetDim(da,3);CHKERRQ(ierr);
  ierr = DMDASetBoundaryType(da,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE);CHKERRQ(ierr);
  ierr = DMDASetStencilType(da,DMDA_STENCIL_STAR);CHKERRQ(ierr);
  ierr = DMDASetSizes(da,3,3,3);CHKERRQ(ierr);
  ierr = DMDASetNumProcs(da,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE);CHKERRQ(ierr);
  ierr = DMDASetDof(da,dof);CHKERRQ(ierr);
  ierr = DMDASetStencilWidth(da,1);CHKERRQ(ierr);
  ierr = DMDASetOwnershipRanges(da,NULL,NULL,NULL);CHKERRQ(ierr);
  ierr = DMSetFromOptions(da);CHKERRQ(ierr);
  ierr = DMSetUp(da);CHKERRQ(ierr);

  ierr = DMCreateGlobalVector(da,&x);CHKERRQ(ierr);
  ierr = DMCreateGlobalVector(da,&b);CHKERRQ(ierr);
  ierr = DMSetMatType(da,MATAIJ);CHKERRQ(ierr);
  ierr = DMCreateMatrix(da,&A);CHKERRQ(ierr);
  ierr = VecSet(b,zero);CHKERRQ(ierr);

  /* Test sbaij matrix */
  flg  = PETSC_FALSE;
  ierr = PetscOptionsGetBool(NULL,"-test_sbaij",&flg,NULL);CHKERRQ(ierr);
  if (flg) {
    Mat sA;
    ierr = MatSetOption(A,MAT_SYMMETRIC,PETSC_TRUE);CHKERRQ(ierr);
    ierr = MatConvert(A,MATSBAIJ,MAT_INITIAL_MATRIX,&sA);CHKERRQ(ierr);
    ierr = MatDestroy(&A);CHKERRQ(ierr);
    A    = sA;
  }

  ierr = KSPCreate(PETSC_COMM_WORLD,&ksp);CHKERRQ(ierr);
  ierr = KSPSetFromOptions(ksp);CHKERRQ(ierr);
  ierr = KSPSetOperators(ksp,A,A,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
  ierr = KSPGetPC(ksp,&pc);CHKERRQ(ierr);
  ierr = PCSetDM(pc,(DM)da);CHKERRQ(ierr);

  ierr = KSPSolve(ksp,b,x);CHKERRQ(ierr);

  /* check final residual */
  flg  = PETSC_FALSE;
  ierr = PetscOptionsGetBool(NULL, "-check_final_residual", &flg,NULL);CHKERRQ(ierr);
  if (flg) {
    Vec       b1;
    PetscReal norm;
    ierr = KSPGetSolution(ksp,&x);CHKERRQ(ierr);
    ierr = VecDuplicate(b,&b1);CHKERRQ(ierr);
    ierr = MatMult(A,x,b1);CHKERRQ(ierr);
    ierr = VecAXPY(b1,-1.0,b);CHKERRQ(ierr);
    ierr = VecNorm(b1,NORM_2,&norm);CHKERRQ(ierr);
    ierr = PetscPrintf(PETSC_COMM_WORLD,"Final residual %g\n",norm);CHKERRQ(ierr);
    ierr = VecDestroy(&b1);CHKERRQ(ierr);
  }

  ierr = KSPDestroy(&ksp);CHKERRQ(ierr);
  ierr = VecDestroy(&x);CHKERRQ(ierr);
  ierr = VecDestroy(&b);CHKERRQ(ierr);
  ierr = MatDestroy(&A);CHKERRQ(ierr);
  ierr = DMDestroy(&da);CHKERRQ(ierr);
  ierr = PetscFinalize();
  return 0;
}
Exemple #5
0
int main(int argc,char **argv)
{
  KSP            ksp;
  DM             da;
  UserContext    user;
  PetscReal      norm;
  const char     *bcTypes[2] = {"dirichlet","neumann"};
  PetscErrorCode ierr;
  PetscInt       bc;

  PetscInt       i,j,k,mx,my,mz,xm,ym,zm,xs,ys,zs;
  PetscScalar    Hx,Hy,Hz;
  PetscScalar    ***array;
  Vec            x,b,r;
  Mat            J;

  PetscInitialize(&argc,&argv,(char *)0,help);
  
  ierr = KSPCreate(PETSC_COMM_WORLD,&ksp);CHKERRQ(ierr);
  ierr = DMDACreate3d(PETSC_COMM_WORLD,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,DMDA_BOUNDARY_NONE,DMDA_STENCIL_STAR,12,12,12,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,1,1,0,0,0,&da);CHKERRQ(ierr);  
  ierr = DMDASetInterpolationType(da, DMDA_Q0);CHKERRQ(ierr);  

  ierr = KSPSetDM(ksp,da);CHKERRQ(ierr);
  
  ierr = PetscOptionsBegin(PETSC_COMM_WORLD, "", "Options for the inhomogeneous Poisson equation", "DM");
  bc          = (PetscInt)NEUMANN;
  ierr        = PetscOptionsEList("-bc_type","Type of boundary condition","ex34.c",bcTypes,2,bcTypes[0],&bc,PETSC_NULL);CHKERRQ(ierr);
  user.bcType = (BCType)bc;
  ierr = PetscOptionsEnd();
  
  ierr = KSPSetComputeRHS(ksp,ComputeRHS,&user);CHKERRQ(ierr);
  ierr = KSPSetComputeOperators(ksp,ComputeMatrix,&user);CHKERRQ(ierr);
  ierr = KSPSetFromOptions(ksp);CHKERRQ(ierr);
  ierr = KSPSolve(ksp,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
  ierr = KSPGetSolution(ksp,&x);CHKERRQ(ierr);
  ierr = KSPGetRhs(ksp,&b);CHKERRQ(ierr);
  ierr = KSPGetOperators(ksp,PETSC_NULL,&J,PETSC_NULL);CHKERRQ(ierr);
  ierr = VecDuplicate(b,&r);CHKERRQ(ierr);

  ierr = MatMult(J,x,r);CHKERRQ(ierr);
  ierr = VecAXPY(r,-1.0,b);CHKERRQ(ierr);
  ierr = VecNorm(r,NORM_2,&norm);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Residual norm %G\n",norm);CHKERRQ(ierr); 
  
  ierr = DMDAGetInfo(da, 0, &mx, &my, &mz, 0,0,0,0,0,0,0,0,0);CHKERRQ(ierr);
  Hx   = 1.0 / (PetscReal)(mx);
  Hy   = 1.0 / (PetscReal)(my);
  Hz   = 1.0 / (PetscReal)(mz);
  ierr = DMDAGetCorners(da,&xs,&ys,&zs,&xm,&ym,&zm);CHKERRQ(ierr);
  ierr = DMDAVecGetArray(da, x, &array);CHKERRQ(ierr);

  for (k=zs; k<zs+zm; k++){
    for (j=ys; j<ys+ym; j++){
      for(i=xs; i<xs+xm; i++){
	array[k][j][i] -= 
	  PetscCosScalar(2*PETSC_PI*(((PetscReal)i+0.5)*Hx))*
	  PetscCosScalar(2*PETSC_PI*(((PetscReal)j+0.5)*Hy))*
	  PetscCosScalar(2*PETSC_PI*(((PetscReal)k+0.5)*Hz));
      }
    }
  }
  ierr = DMDAVecRestoreArray(da, x, &array);CHKERRQ(ierr);
  ierr = VecAssemblyBegin(x);CHKERRQ(ierr);
  ierr = VecAssemblyEnd(x);CHKERRQ(ierr);

  ierr = VecNorm(x,NORM_INFINITY,&norm);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Error norm %g\n",norm);CHKERRQ(ierr); 
  ierr = VecNorm(x,NORM_1,&norm);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Error norm %g\n",norm/((PetscReal)(mx)*(PetscReal)(my)*(PetscReal)(mz)));CHKERRQ(ierr); 
  ierr = VecNorm(x,NORM_2,&norm);CHKERRQ(ierr);
  ierr = PetscPrintf(PETSC_COMM_WORLD,"Error norm %g\n",norm/((PetscReal)(mx)*(PetscReal)(my)*(PetscReal)(mz)));CHKERRQ(ierr); 

  ierr = VecDestroy(&r);CHKERRQ(ierr);
  ierr = KSPDestroy(&ksp);CHKERRQ(ierr);
  ierr = DMDestroy(&da);CHKERRQ(ierr);
  ierr = PetscFinalize();
  return 0;
}