I would like to report a problem that I am not sure if it is a bug. I would like to obtain the stiffness matrix of a truss in openseespy. I use printA and FullGeneral system after ops.analysis. However, if the truss is unstable, it returns this error and quit the python console. It works properly if truss is stable. Returned error is:
FATAL FullGenLinSOE::getX - vectX == 0
Would you please help me out how to achieve a stiffness matrix for a non-internal stable truss?
Thanks for your reply. I guess in the current state, OpenSees can not return the stiffness matrix before performing analysis. As a suggestion, it would be great to achieve the stiffness matrix before analysis. I am not sure if it is possible.