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


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