[tng-devel] MUMPS binding in tmath/sparse

[Sebastian Wolff <sw@xxxxxxxxxxxxxxxxxxxx>]

I made some changes to the interface class of sparse solvers and 
applied them to MUMPS.

It is now possible to

- solve A*x=b, where x,b are dense vectors AND matrices,
- solve transpose(A)*x=b.
- The factorizing method SparseSolver:Compute() distinguishes between 
symmetric and general sparse matrices.

Regarding optimizing the memory use of MUMPS I was checking the MUMPS 
documentation. The problem is, that the given data buffers of the input 
data (arrays for x,y,value) may be altered by MUMPS. For example, 
duplicate entries are merged (ok - we can ensure this before pushing 
data to MUMPS) and nonzero entries are created where MUMPS believes it 
is necesary (can not be ensured by us or do we want to scan MUMPS' 
source code with each release?).

I, therefore, discourage to use the data buffer of our sparse matrices 
as direct input for MUMPS and recommend to create a copy.

Regards,
SW