[petsc-dev] MatWrapML_SHELL

[Barry Smith]

On May 9, 2012, at 8:25 PM, John Fettig wrote:

> In the function MatWrapML_SHELL, there is a return without creating the shell 
> matrix.  I have two questions about it:
> 
>   m = mlmat->outvec_leng; 
>   n = mlmat->invec_leng;
>   if (!m || !n){
>     newmat = PETSC_NULL;
>     PetscFunctionReturn(0);
>   }
> 
> 1) Should there be an error generated here?
> 
> 2) If not, why does the function return without generating the matrix?  This 
> can result in deadlock if some processes return in this clause and some do 
> not.  The ones that do not get caught in the MatCreateShell() call.
> 
> Regards,
> John
> 

   John,

    Is this a concern based on a code inspection, or do you have a particular 
case where it crashes? If you have a crashing case could you please send it to 
us?

    Thanks

   Barry