[tng-users] TMATH - bug in symmetric sparse matrices!

[Sebastian Wolff <sw@xxxxxxxxxxxxxxxxxxxx>]

There is a serious bug in Eigen library regarding symmetric sparse 
matrices. Therefore I encourage not to use them .

Description:
Symmetric sparse matrices should contain only the lower triangular part 
of the matrix and behave as if the (non stored) uppertriangular part 
would exist. This happened to be the case. But Eigen always stored the 
full matrix regardless the specified memory layout. That means: 
Operators worked, but backends like MUMPS did not. I made some 
experiments with the code to trick around that, but as a result the 
class tmath.SymSparseMatrix should be considered as being broken. We 
have to wait for Eigen 3.0 which is supposed to be released within the 
next 12 months.

Best regards SW