adding better support for petsc4py in core PETSc

[Barry Smith]

   Lisandro,

     Go ahead and add it.

    Barry

On May 30, 2008, at 10:55 AM, Lisandro Dalcin wrote:

> I want to ask all you for adding better support for petsc4py in core  
> PETSc.
>
> All what I need to to add to opaque pointers in the base PetscObject
> structure, like this
>
> void *pycontext
> PetscErrorcode  (*pydestroy)(void*)
>
> As you see, this will not make core PETSc depend on Python in any way.
> Additionally, the extra memory overhead is small, just to pointers..
>
> My intention is to put a Python dictionary in the pycontext pointer,
> and call pydestroy function pointer (I'll set if when needed) at the
> time PetscHeaderDestroy is called.
>
> Such a feature is currently being emulated with PetscContainer and
> PetscObjectCompose, but I would really like to cleanup this hackery
> and implement things the right way.
>
> I've started to migrate my SWIG-based wrappers to use Cython. This is
> preliminar and not yet ready for public consumption, but at firts I
> anticipate this approach if far easier to understand, extend, and
> maintain than the previous one. In the near future, making petsc4py
> interoperate with C/C++/Fortran user code will be possible and easy.
>
> For example, I saw the new Picard implementation in SNES. Such a
> feature could be implemented with a few lines of pure Python code, no
> point to have to write a full SNES type implementation (unless it is
> really needed). Just write in Python a custom nonlinear solver, and
> now run your C/C++/Fortran code with an special option in the command
> line, and PETSc picks-up and used the Python code implementing your
> solver.
>
>
> -- 
> Lisandro Dalcín
> ---------------
> Centro Internacional de Métodos Computacionales en Ingeniería (CIMEC)
> Instituto de Desarrollo Tecnológico para la Industria Química (INTEC)
> Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
> PTLC - Güemes 3450, (3000) Santa Fe, Argentina
> Tel/Fax: +54-(0)342-451.1594
>
>