[petsc-users] --with-64-bit-indices=1

[Smith, Barry F.]

> On Nov 4, 2019, at 2:14 PM, Anthony Paul Haas via petsc-users <petsc-users at mcs.anl.gov> wrote:
> 
> Hello,
> 
> I ran into an issue while using Mumps from Petsc. I got the following error (see below please). Somebody suggested that I compile Petsc with --with-64-bit-indices=1. Will that suffice?

Currently PETSc and MUMPS do not work together with --with-64-bit-indices=1. 

> Also I compiled my own version of Petsc on Cray Onyx (HPCMP) but although I compiled --with-debugging=0,  Petsc was very very slow (compared to the version of Petsc available from the Cray admins). Do you have a list of flags that I should compile Petsc with for Cray supercomputers?

No idea why it would be particularly slower. No way to know what compiler options they used.

You also have a choice of different compilers on Cray, perhaps that makes a difference.

> 
> Thanks,
> 
> Anthony
> 
> INFOG(1)=-51. I saw in the mumps manual that:
> 
> An external ordering (Metis/ParMetis, SCOTCH/PT-SCOTCH, PORD), with 32-bit default
> integers, is invoked to processing a graph of size larger than 2^31-1. INFO(2) holds the size
> required to store the graph as a number of integer values;

   This is strange. Since PETSc cannot when using 32 bit indices produce such a large graph I cannot explain how this message was generated. Perhaps there was an integer overflow


> 
>