Convergence question


I have a model with some contact surfaces. The problem is that 20% of the times I try to solve it, Calculix does not converge and maybe sometimes it will produce multiple result data sets. Is this something expected? Each time I feed the same .inp file in Calculix so probably it is something randomized in the solvers inside Calculix. Has anybody seen this also?

Thank you in advance!

Which version of CalculiX and which solver are you using ? Have you tried improving convergence for this model ?

I use Calculix 2.20 and I am using the default solver which is PastiX if I am correct.
By improving convergence you mean to change the covergence criteria?

It would be best to try with other solvers, this one is still relatively new.

This rarely helps. What I mean is changing the model in such a way that it converges better. For example, using displacement control instead of load control.

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I have seen this before on windows + Pastix.

By other hand Pastix Mixed precision internal variable seem to give some issues too.
Try Pardiso.


Hi, I’m interested in this topic…could you post the .inp file for this problem? many thanks.

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