[petsc-users] MUMPS failure

[Barry Smith]

   In a pure Fortran code using -fdefault-integer-8 is probably fine. But MUMPS is a mixture of Fortran and C code and PETSc uses MUMPs C interface. The  -fdefault-integer-8 doesn't magically fix anything in the C parts of MUMPS.  I also don't know about MPI calls and if they would need editing.

   I am not saying it is impossible to get it to work but one needs are to insure the C portions also switch to 64 bit integers in a consistent way. This may be all doable bit is not simply using -fdefault-integer-8 on MUMPS.

  Barry


> On Mar 23, 2021, at 12:07 AM, Sanjay Govindjee <s_g at berkeley.edu> wrote:
> 
> Barry,
> I am curious about your statement "does not work generically".  If I compile with -fdefault-integer-8,
> I would assume that this produces objects/libraries that will use 64bit integers.  As long as I have not declared
> explicit kind=4 integers, what else could go wrong.
> -sanjay
> 
> PS: I am not advocating this as a great idea, but I am curious if there or other obscure compiler level things that could go wrong. 
> 
> 
> On 3/22/21 8:53 PM, Barry Smith wrote:
>> 
>> 
>>> On Mar 22, 2021, at 3:24 PM, Junchao Zhang <junchao.zhang at gmail.com <mailto:junchao.zhang at gmail.com>> wrote:
>>> 
>>> 
>>> 
>>> 
>>> On Mon, Mar 22, 2021 at 1:39 PM Barry Smith <bsmith at petsc.dev <mailto:bsmith at petsc.dev>> wrote:
>>> 
>>>    Version of PETSc and MUMPS? We fixed a bug in MUMPs a couple years ago that produced error messages as below. Please confirm you are using the latest PETSc and MUMPS. 
>>> 
>>>    You can run your production version with the option -malloc_debug ; this will slow it down a bit but if there is memory corruption it may detect it and indicate the problematic error. 
>>> 
>>>     One also has to be careful about the size of the problem passed to MUMPs since PETSc/MUMPs does not fully support using all 64 bit integers. Is it only crashing for problems near 2 billion entries in the sparse matrix?
>>>  "problems near 2 billion entries"?  I don't understand. Should not be an issue if building petsc with 64-bit indices.
>> 
>>   MUMPS does not have proper support for 64 bit indices. It relies on add-hoc Fortran compiler command line options to support to converting integer to 64 bit integers and does not work generically. Yes, Fortran lovers have been doing this for 30 years inside their applications but it does not really work in a library environment. But then a big feature of Fortran is "who needs libraries, we just write all the code we need" (except Eispack,Linpack,LAPACK :=-).
>> 
>>> 
>>> 
>>>      valgrind is the gold standard for detecting memory corruption. 
>>> 
>>> Barry
>>> 
>>> 
>>>> On Mar 22, 2021, at 12:56 PM, Chris Hewson <chris at resfrac.com <mailto:chris at resfrac.com>> wrote:
>>>> 
>>>> Hi All,
>>>> 
>>>> I have been having a problem with MUMPS randomly crashing in our program and causing the entire program to crash. I am compiling in -O2 optimization mode and using --download-mumps etc. to compile PETSc. If I rerun the program, 95%+ of the time I can't reproduce the error. It seems to be a similar issue to this thread:
>>>> 
>>>> https://lists.mcs.anl.gov/pipermail/petsc-users/2018-October/036372.html <https://lists.mcs.anl.gov/pipermail/petsc-users/2018-October/036372.html>
>>>> 
>>>> Similar to the resolution there I am going to try and increase icntl_14 and see if that resolves the issue. Any other thoughts on this?
>>>> 
>>>> Thanks,
>>>> 
>>>> Chris Hewson
>>>> Senior Reservoir Simulation Engineer
>>>> ResFrac
>>>> +1.587.575.9792
>>> 
>> 
> 

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