Topic: Buckling Eigenvector

Hi everyone!

I was checking the OOFEM example about buckling (test->sm->linstab_beam2d.in). Regarding Eigen Value It works perfectly, however I am not sure about Eigenvector. For example, in output file all the displacements at the eigen vector 1 are null except the DOF 1 (x) which is forced to 3. I expected typical shape of buckling in a cantilever. Could anyone explain to me why are these values 0? I mean, why this is the shape of eigenvector 1? Note if you change the input file and you do not force any displacement, the eigenvalue no 1 does not change but the eigenvector is null in all DOF.
Thank you in advance.

Best Regards,

Javier Sánchez-Haro.