The FEAST eigensolver stores the DoF of VELOCITY and ACCELERATION

[loumalouomega]

Regarding #138 , I discover that the DoF stored in the EIGENVECTORS_MATRIX are additionally to the DISPLACEMENT the temporal derivatives VELOCITY and ACCELERATION, but like these DoF are not considered in the system K-M w^2=0, which are solved with the time scheme, then they are going to be always zero, so storing them increases the database size for the eigenvectors 3 times.

Additionally this means need to know which is the order for the DoF in the EIGENVECTORS_MATRIX to be able to process this info.

[msandre]

Yes, as observed there is storage overhead with the current implementation. The reason for the current approach is to be general enough to accommodate different types of problems, structural or other.

[msandre]

Note that this is done in the eigensolver_strategy.hpp which should work independent of the application.

[msandre]

@lorenzogracia or @loumalouomega if for the structural mechanics app it makes sense, you can try defining AddDofs() in structural_mechanics_eigensolver.py to only add DISPLACEMENT. This should solve the storage problem while keeping the strategy general.

[loumalouomega]

Maybe the easiest way is, despite is technically a dynamic problem, consider it as a static problem, this way just the DISPLACEMENT DoF will be added.

[msandre]

I think dynamic is more meaningful since it relates to the dynamic problem and there is possibly also static buckling.

[loumalouomega]

Yes, is meaningful, but it is the easiest way to solve that problem, in a real dynamic problem the time derivatives are computed using a time scheme, in this case we just take the stiffness matrix and the mass matrix in order to compute the eigenfrequencies.

[msandre]

It's a minor change so I added the AddDofs() in 8798fd7ddb3d57f72e6a0996bc7f549522c260df .

[loumalouomega]

Thanks @msandre