[petsc-users] transfer vector data diagonally on DA

[Matthew Knepley]

On Mon, Apr 2, 2012 at 4:53 PM, khalid ashraf <khalid_eee at yahoo.com> wrote:

> Thanks Matt. It works now.
>
> I have another problem. I am writing this program.
>

1) Always test on 2 procs once

2) I have no idea what you actually want to do. However, it really simple
to just print out
    the indices you are using in row[] and the values in bodyFx[] and check
that VecSetValues()
    is working as you expect.

   Matt


>
>  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 at gmail.com>
> *To:* khalid ashraf <khalid_eee at yahoo.com>; PETSc users list <
> petsc-users at 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 at 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 at mcs.anl.gov>
> *To:* khalid ashraf <khalid_eee at yahoo.com>; PETSc users list <
> petsc-users at 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 at 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
>
>
>


-- 
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
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