[petsc-dev] SNESLineSearchApply_BT logic divergence

[Matthew Knepley]

On Sat, Jun 16, 2012 at 12:03 AM, Daniel Lowell <redratio1 at gmail.com> wrote:

> Hey Satish,
>
> So I'm having an issue with this function:
>
> *#define PetscObjectComposedDataGetReal <http://www.mcs.anl.gov/petsc/petsc-current/include/petsc-private/docs/manualpages/Sys/PetscObjectComposedDataGetReal.html#PetscObjectComposedDataGetReal>(obj,id,data,flag)                            \**((((obj)->realcomposedstate && ((obj)->realcomposedstate[id] == (obj)->state))?  \**(data = (obj)->realcomposeddata[id],flag = PETSC_TRUE <http://www.mcs.anl.gov/petsc/petsc-current/include/petsc-private/docs/manualpages/Sys/PETSC_TRUE.html#PETSC_TRUE>) : (flag = PETSC_FALSE <http://www.mcs.anl.gov/petsc/petsc-current/include/petsc-private/docs/manualpages/Sys/PETSC_FALSE.html#PETSC_FALSE>)),0)*
>
>
> Called from VecNorm which is called from SNESLineSearchApply_BT
>
> I have two examples running one is the vanilla ex14 using my GPU vector
> and matrix type.  The other example is a variant of ex14test where I am
> implementing GPU formfunction and formjacobian.
> ex14 vanilla runs through correctly, however ex14test diverges in the
> logic within VecNorm, specifically line 164:
>  /*
>    * Cached data?
>    */
>   if (type!=NORM_1_AND_2) {
>     ierr = PetscObjectComposedDataGetReal
> ((PetscObject)x,NormIds[type],*val,flg);CHKERRQ(ierr);
>     if (flg) PetscFunctionReturn(0);
>   }
>
> The ex14 detects there is a "real" part, however the ex14test does not and
> VecNorm returns.
>
> "val" in VecNorm is PetscReal gnorm = fnorm defined in
> SNESLineSearchApply_BT.
> For ex14:       val[0]=3.44e-317, val[1]: 0.580
> For ex14test: val[0]=3.44e-317, val[1]: 0.029
>
>
> This difference makes SNESLineSearchApply_BT branch into different
> execution paths.
>
> I'm not sure where the issue could have come from. Any ideas?
>

If you change values in a Vec, you must increment the internal state, since
we cache norms.
The internal functions for array getting do this automatically, so I am not
sure why this is
messing up. Did you bypass them?

   Matt


>
> --
> Daniel Lowell
>
>


-- 
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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