[petsc-dev] changed ISCreateGeneral/NC/WithArray()

Lisandro Dalcin dalcinl at gmail.com
Sun Oct 3 17:45:01 CDT 2010


On 3 October 2010 14:57, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
>   I find the three routines ISCreateGeneral(), ISCreateGeneralNC() and ISCreateGeneralWithArray() to be confusing and code redundant.
>
>   Therefore in PETSc-dev I have introduced
>
> /*E
>    PetscCopyMode  - Determines how an array passed to certain functions is copied or retained
>
>   Level: beginner
>
> $   PETSC_COPY_VALUES - the array values are copied into new space, the user is free to reuse or delete the passed in array
> $   PETSC_OWN_POINTER - the array values are NOT copied, the object takes ownership of the array and will free it later, the user cannot change or
> $                       delete the array. The array MUST have been obtained with PetscMalloc(). Hence this mode cannot be used in Fortran.
> $   PETSC_USE_POINTER - the array values are NOT copied, the object uses the array but does NOT take ownership of the array. The user cannot use
>                        the array but the user must delete the array after the object is destroyed.
>
> E*/
> typedef enum { PETSC_COPY_VALUES, PETSC_OWN_POINTER, PETSC_USE_POINTER} PetscCopyMode;
> extern const char *PetscCopyModes[];
>
> and merged  ISCreateGeneral/NC/WithArray() into a single routine with an additional PetscCopyMode argument.
>
> I have also merged ISLocalToGlobalMappingCreate() and ISLocalToGlobalMappingCreateNC() into a single routine.
>
> There may be other places we can use this paradigm in the future, keep your eyes open,
>
>  Happy computing,
>
>    Barry
>

I would prefer to have:

ISCreateGeneralWithArray(comm,n,ptr,copy_mode,&is);

and then implement

ISCreateGeneral(comm,n,ptr,&is) {
return ISCreateGeneralWithArray(comm,n,ptr,PETSC_COPY_VALUES,&is);
}

What do you think?

-- 
Lisandro Dalcin
---------------
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