[Trilinos-Users] Sparse matrix and Anasazi Solvers,

[Mike Atambo]

Hi,
Im unable to get matrices,  ( say a sparse matrix with
885500 non zeros  out of  about  2822796900 )   to converge
with the block davison or the krylov solver,

I had a look at the condition number reported by the 'ILUT' preconditioner
and it seems to grow rather quickly for my  problems,  ( 9x9  with 39 non
zeros has  condition number= 10,   and at    25*25 and 100 non zeros the
condition number is at 250).

Im able to solve all these examples here using scipy.sparse.eigs  (it uses
ARPACK),  so there is probably something that im not doing right.

The block-davidson solver with 'ILUT' pre-conditioner   work for the small
systems above,   but  beyond  300*300 matrix size,  this is not longer
true.

At the moment im  following these steps.

1.  Create and initialize a matrix,
2.  Create an anasazi basic eigenproblem,
3.  Create a  solver (either block davidson or krylov-shur)
4.   Get solution,

Id like to find out whether there is a way to tell why the system  im
working on seems
to be  unable to converge.  Any help would be appreciated.

Mike


-- 
M. O. Atambo
mikeat4999 at gmail.com
matambo at ictp.it
Ext .139
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