Thanks Matt. It works now. 

I have another problem. I am writing this program. 

 

 for (k=zs; k<zs+zm; k++) {

  for (j=ys; j<ys+ym; j++) {

  for (i=xs; i<xs+xm; i++) {

 if ( i!=(mx-1) || j!=my-1 || k!=mz-1)

{

bodyFx[0]=1;

bodyFx[1]=-0.3;

bodyFx[2]=-0.3;

bodyFx[3]=-0.3;

row[0]=k*mx*my+j*mx+i;

row[1]=k*mx*my+j*mx+i+1;

row[2]=k*mx*my+(j+1)*mx+i;

row[3]=(k+1)*mx*my+j*mx+i;

VecSetValues(fx_test,4,row,bodyFx,ADD_VALUES);

}

VecAssemblyBegin(fx_test);

VecAssemblyEnd(fx_test);

Output: Print fx_test

 Here fx_test is a global vector. This program gives correct output on 1 proc. but on 4 processors,

the program runs but the outputs are wrong.

I also tried

 for (k=zs; k<zs+zm; k++) {

  for (j=ys; j<ys+ym; j++) {

  for (i=xs; i<xs+xm; i++) {

 if ( i!=(mx-1) || j!=my-1 || k!=mz-1)

{

bodyFx[0]=1;

bodyFx[1]=-0.3;

bodyFx[2]=-0.3;

bodyFx[3]=-0.3;

 fx1_localptr[k][j][i+1]+=bodyFx[4];

 fx1_localptr[k][j+1][i]+=bodyFx[3];

 fx1_localptr[k+1][j][i]+=bodyFx[1];

 fx1_localptr[k][j][i]+=bodyFx[0];

}

Here, fx1_localptr is an array from a local vector that is communicated from the global vector fx_test.

In this case as well, I get similar errors. 

Thanks.

Khalid

Some final numbers of the vector with 8*8*6 grid, 4 proc,  

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

1.0000000000000009e-01

1.0000000000000009e-01

1.0000000000000009e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

0.0000000000000000e+00

4.0000000000000002e-01

1.0000000000000009e-01

1.0000000000000009e-01

1.0000000000000009e-01

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

1.0000000000000009e-01

1.0000000000000009e-01

1.0000000000000009e-01

-2.9999999999999999e-01

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

Some final numbers of the vector with 8*8*6 grid, 1 proc,  

0.0000000000000000e+00

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

0.0000000000000000e+00

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

0.0000000000000000e+00

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

-2.9999999999999999e-01

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

0.0000000000000000e+00

                               

---

From: Matthew Knepley <knepley@gmail.com>
To: khalid ashraf <khalid_eee@yahoo.com>; PETSc users list <petsc-users@mcs.anl.gov>
Sent: Monday, April 2, 2012 5:41 AM
Subject: Re: [petsc-users] transfer vector data diagonally on DA

On Mon, Apr 2, 2012 at 3:36 AM, khalid ashraf <khalid_eee@yahoo.com> wrote:

Hi Jed,

I am using petsc/3.1 and the include file "petscdmda.h" is not working. I am using the "petscda.h"

and DACreate3D. 

unew_localptr[][][] is from a global vector using VecGetArray

u_localptr[][][] is from a local vector communicated from a global vector.

I tried 

unew_localptr[k][j][i]=u_localptr[k-1][j-1][i-1]

but it gives Segmentation Violation error. 

I would guess (because you provide almost no information about what you are doing), that

this is a domain on the edge. If you truly mean to have a periodic domain, you must set that in the

creation call. Then the local vector will also ghost regions outside the domain boundary.

   Matt

 

I also tried unew_localptr[k][j][i]=u_localptr[k][j+1][i+1] which works but 

unew_localptr[k][j][i]=u_localptr[k+1][j+1][i+1] or unew_localptr[k][j][i]=u_localptr[k][j-1][i-1]

does not work. I am running the program on4 processors.

Thanks.

  ierr = DACreate3d(PETSC_COMM_WORLD,DA_YPERIODIC,DA_STENCIL_BOX,appctx.l,appctx.m,appctx.n,

                    PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,1,1,PETSC_NULL,PETSC_NULL,PETSC_NULL,

                    &appctx.da);CHKERRQ(ierr);

 for (k=zs; k<zs+zm; k++) {

  for (j=ys; j<ys+ym; j++) {

  for (i=xs; i<xs+xm; i++) {

  if(i!=0 || j!=0 || k!=0|| i!=mx-1 || j!=my-1 || k!=mz-1)

  unew_localptr[k][j][i]=u_localptr[k+1][j+1][i+1];

}}}

---

From: Jed Brown <jedbrown@mcs.anl.gov>
To: khalid ashraf <khalid_eee@yahoo.com>; PETSc users list <petsc-users@mcs.anl.gov>
Sent: Sunday, April 1, 2012 10:07 PM
Subject: Re: [petsc-users] transfer vector data diagonally on DA

On Sun, Apr 1, 2012 at 22:01, khalid ashraf <khalid_eee@yahoo.com> wrote:

I want to transfer vector data diagonally in the DA grid like 

 for (k=zs; k<zs+zm; k++) {

  for (j=ys; j<ys+ym; j++) {

  for (i=xs; i<xs+xm; i++) {

if(i!=mx-1 || j!=my-1 || k!=mz-1){

u_new[k+1][j+1][i+1]=u[k][j][i];}

}}}

Could you please suggest the best way to do it minimizing interprocessor assignments.

Both are on the same DMDA?

Communicate U to Ulocal (DMGlobalToLocalBegin/End) using a BOX stencil with width at least 1, get the global array u_new[][][] from UGlobalNew and the local arrays u[][][] from Ulocal, then assign u_new[k][j][i] = u[k-1][j-1][i-1].

--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener