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

[Barry Smith]

On Oct 3, 2010, at 5:58 PM, Jed Brown wrote:

> Can anyone think of a better mnemonic, I find PETSC_OWN_VALUES to be ambiguous without reading the man page?

   It is PETSC_OWN_POINTER (so clearly it is ambiguous because you didn't read the man page :-).

   I agree with you about the mnemonic not being great, but couldn't come up with something short and not using CS-slang like deep copy versus shallow copy.... 

   It could be PETSC_OWN_VALUES and PETSC_USE_VALUES instead of pointer ? PETSC_TAKE_OWNERSHIP_OF_VALUES is too long.

   Barry


> 
> Jed
> 
> 
>> On Oct 3, 2010 7:57 PM, "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
>> 
>