Writing tcl code to Python

[Sonice]

I tried to convert a 3d general example available in OpenSees website into python using OpenSeesPy. On analysis, Python version is giving following errors:
1) ArpackSolver::Error with _saupd info = -9
Starting vector is zero.
WARNING DirectIntegrationAnalysis::eigen() - EigenSOE failed in solve()
WANRING failed to do eigen analysis
Traceback (most recent call last):
File "F:/C_OpenSees/Python_transfereed_ExactCopy/General_RC_Section_Exact.py", line 217, in <module>
eigenValues = ops.eigen(numEigen)
opensees.OpenSeesError: See stderr output

2) Analysis has also failed (-3).

I used Model viewer from openseesPy, and also from matlab code provided by D. Vamvatsikos, and both models (from tcl and python) are same. I even compared each values from print (tcl) and printModel (Python), and both are same. What could be the reason for the error in python code?

Thanks and Regards,
Sanish Bhochhibhoya

[mhscott]

The models are *not* the same! You probably forgot mass or something that will make the eigenvalue solver fail.

[mhscott]

Or you don't have proper constraints to prevent rigid body motion.