Re: [tng-devel] MUMPS binding in tmath/sparse

[Sebastian Wolff <sw@xxxxxxxxxxxxxxxxxxxx>]

Btw.

It would be interesting to compare the efficiency of SymSparseMatrix 
and TNGSparseArray,
particularly

- inserting values (maybe to test by converting both from SparseMatrix)
- products with vectors and matrices, scalars
- sums with other symmetric sparse matrices

That way, we can ensure that the better algorithms of both should be 
merged into
SymSparseMatrix.

Furthermore, I could imagine the appearance of a new data type:

SymTripletMatrix

which stores its values by separate arrays for 'value', 'i' and 'j'. It 
should follow the
design of tmath.SparseMatrix though.

Regards
SW

Zitat von 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