On 01/02/2017 07:45 AM, [email protected] wrote:
I also don't know how the first method can be implemented. I read the above
models in the book By Neto, Peric and Owen “Computational method for
plasticity”. They have been computed the determinant of the stiffness matrix
during solving the linear system using the classical frontal method. In the
frontal method, the linear system is solved by Gauss elimination. Now I am
working on the last criterion, however, for my problems the first one will
work better.
Using a frontal solver (=direct solver) gives you access to the diagonal
elements of the L and U factors, and their product is the determinant. But
this of course only allows you to solve relatively small problems. I am
surprised that a book published in 2008 would still advocate for such an
algorithm. I don't think this information is easily available using iterative
solvers but as Denis pointed out, it is conceivable that one can get some
information from the local matrices. For example, if all local matrices are
positive definite, then so is the global matrix.
Best
W.
--
------------------------------------------------------------------------
Wolfgang Bangerth email: [email protected]
www: http://www.math.colostate.edu/~bangerth/
--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see
https://groups.google.com/d/forum/dealii?hl=en
---
You received this message because you are subscribed to the Google Groups "deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
For more options, visit https://groups.google.com/d/optout.
