error in volume optimization

[DibyaR Prakash]

Hello Exciting user

I am a beginner just trying to learn this code. I have tried some examples successfully but I am getting following error for the volume optimization . Which is an example for Ag. by giving th commant

#"CHECKFIT-energy-vs-volue.py"

Enter lattice symmetry code [default 0] >>>> 3

Verification lattice symmetry code      >>>> 3

Traceback (most recent call last):

  File "./CHECKFIT-energy-vs-volume.py", line 98, in <module>

    fitr = numpy.polyfit(strain,energy,order_of_fit)

  File "/usr/lib64/python2.6/site-packages/numpy/lib/polynomial.py", line 466, in polyfit

    raise TypeError, "expected non-empty vector for x"

TypeError: expected non-empty vector for x

Please suggest me some solutions.

With regards 

Rai