[petsc-dev] DMCreateMatrix_Shell

[Smith, Barry F.]

  Hmm, why is this check wrong (though it may be incomplete)? Is there an example where it triggers an error when it shouldn't?

   It is my understanding that the check is there to make sure if the user requested a particular matrix type then it won't return a different type that is unexpected for the user (the AIJ checks are just to handle MATAIJ vs MATSEQAIJ, MATMPIAIJ).

   Barry


> On Feb 8, 2019, at 5:29 AM, Stefano Zampini via petsc-dev <petsc-dev at mcs.anl.gov> wrote:
> 
> I don’t understand the need of these checks (tacky and incomplete…, as per the comment) 
> 
> https://bitbucket.org/petsc/petsc/src/75aeaa18afd73be7f3020f94b788241b9e0ba3d7/src/dm/impls/shell/dmshell.c#lines-197
> 
> Why are these checks needed? I’m inclined to remove these lines, but I would like some comments before doing it.