[petsc-users] DMPlexCreateLocalVec Within a function

[Matthew Knepley]

On Sat, Apr 16, 2016 at 4:51 AM, Jed Brown <jed at jedbrown.org> wrote:

> Matthew Kury <mkury at berkeley.edu> writes:
>
> > Yes you are correct I am sorry about that. I meant DMGetLocalVector, and
> the ilk.
> >
> > here is a dummy function I am working on to try to figure out what is
> going wrong:
> >   /////////////////////////////////////////////
> >   //    Get the information to operate on
> >   // Make Local Versions
> >   Vec             XLoc;
> >   DM              Xdm;
> >   PetscSection    XSec;
> >   PetscReal *XPoints=NULL;
> >
> >   PetscErrorCode    ierr;
> >
> >
> >   ierr = DMGetLocalVector(msh.dm,&XLoc);chk;
>
> Here, you get XLoc from msh.dm.
>
> >   ierr = DMGetCoordinateDM(msh.dm,&Xdm);chk;
> >   ierr = DMGetCoordinatesLocal(msh.dm, &XLoc);chk;
> >   VecView(XLoc,pview);
> >
> >   ierr = DMDAVecGetArrayRead(Xdm,XLoc,&XPoints);chk;
>

Also here Xdm is supposed to be a DMDA. Is it?

  Matt


> >   ierr = DMDAVecRestoreArrayRead(Xdm,XLoc,&XPoints);chk;
> >
> >   ierr = DMRestoreLocalVector(Xdm,&XLoc);chk;
>
> Here, you return it to Xdm.
>
> > //////////// end of function
> >
> > the error I get that seems to appear after the 2nd call or so is:
> > 0]PETSC ERROR: --------------------- Error Message
> --------------------------------------------------------------
> > [0]PETSC ERROR: Invalid argument
> > [0]PETSC ERROR: Wrong type of object: Parameter # 2
> > [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html
> for trouble shooting.
> > [0]PETSC ERROR: Petsc Release Version 3.6.1, Jul, 22, 2015
> > [0]PETSC ERROR: ./net.out on a arch-darwin-c-debug named
> Matthews-MacBook-Pro-2.local by mkury Sat Apr 16 01:33:34 2016
> > [0]PETSC ERROR: Configure options --with-cc=gcc --with-cxx=g++
> --with-fc=gfortran --download-fblaslapack --download-mpich
> --download-petsc4py --download-triangle --download-chaco --download-metis
> --download-parmetis --download-ctetgen
> > [0]PETSC ERROR: #2294 DMDAVecGetArrayRead() line 299 in
> /usr/local/petsc-3.6.1/src/dm/impls/da/dagetarray.c
>
> This #2294 is nowhere near the top of your stack.  Please check error
> codes.  Running in a debugger would help you understand what is wrong.
>
> > [0]PETSC ERROR: #2295 Element_Investigation_TEST() line 248 in
> /Users/mkury/Documents/Code/petFEM/src/elementFunctions.c
> >
> >
> >
> >
> >
> >
> > thanks again,
> >
> > Matt
> > On Apr 16, 2016, at 1:21 AM, Jed Brown <jed at jedbrown.org> wrote:
> >
> >> Matthew Kury <mkury at berkeley.edu> writes:
> >>
> >>> Hello,
> >>>
> >>>     I have done some reading and I have not been able to find out what
> the proper way to create and use vectors within a function.
> >>>
> >>>     If I have a function that passes in dm and V then:
> >>> +++
> >>>             DMPlexGetLocalVec(dm, &VLocal) ;
> >>
> >> This function doesn't exist, and neither does DMPlexCreateLocalVec (from
> >> the subject of your email), but when I gaze into my crystal ball, it
> >> says you're probably spelling it DMGetLocalVector.  Please send the full
> >> error message.
> >>
> >>>             DMGlobalToLocalBegin(dm,V,INSERT_VALUES,VLocal);
> >>>             DMGlobalToLocalEnd(dm,V,INSERT_VALUES,VLocal) ;
> >>>
> >>>             VecGetArray(VLoc,VLocalArray);
> >>>
> >>>             “Stuff with VLocalArray”
> >>>
> >>>             VecRestoreArray(VLoc,VLocalArray);
> >>>
> >>>             DMLocalToGlobalBegin(dm,VLocal,ADD_VALUES,V);
> >>>             DMLocalToGlobalEnd(dm,VLocal,ADD_VALUES,V);
> >>>
> >>>             DMRestoreLocalVector(dm,&VLocal);
> >>> +++
> >>>
> >>>     The second time I call the function I get errors with the
> VecGetArray() function.  I would appreciate any advice as to what is going
> wrong.
> >>>
> >>> Thank you,
> >>>
> >>> Matthew
>



-- 
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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