[Trilinos-Users] crash using Amesos_superludist

[Travis Austin]

Hi Eric,

>> One specific question I have is whether superLU_dist requires the 
>> global row numbers to be contiguous. I ask because I do not see this 
>> crash in problems where that is the case.
> I do believe that superLU_dist requires the row numbers to be 
> contiguous, though if the matrix is redistributed before the 
> factorization, the matrix values will be imported into a matrix with 
> contiguous, linear maps.  But this isn't really an issue since it seems 
> Amesos is exiting before even reaching this step.

We have diagnosed our issue to the fact that the row numbers are not contiguous
and it appears when digging into Superlu_dist that it needs that or else it can have
memory issues (stepping outside of array bounds).

When you say redistribute are you referring to a routine in Epetra_CrsGraph or
Epetra_CrsMatrix?  I see that Isorropia performs redistribution of Epetra_Matrices
and vectors but we would prefer to avoid that since we are in the last several weeks
of a code release and we would have to deal with any new issues coming from 
Isorropia.

The issue is that we have a column index like [7 8 9 11 12 13] but the global number
of columns is 6 so in superlu_dist it allocates an array of size 6 but tries to access its
12th entry.  

How can we easily change our Graph from [7 8 9 11 12 13] to [0 1 2 3 4 5]?  Any ideas?

> 
> Have you tried the SuperLU_Dist interface in Amesos2?\

Same as above.  We do not have the time now to look at Amesos2.  Possibly in the future.

> 
> `~Eric
> 
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