LinAlgError("Eigenvalues did not converge")

[faraperu]

Dear sir, thanks for your awesome paper. i get the following error. what could be the problem. some times it works and some times it does not .

test_script_PSTme.py:168: RuntimeWarning: Degrees of freedom <= 0 for slice
eigvals, eigvecs = np.linalg.eigh(np.cov(ODhat.T))
C:\Users\Fred\Anaconda2\envs\PST\lib\site-packages\numpy\lib\function_base.py:2480: RuntimeWarning: divid
e by zero encountered in true_divide
c *= np.true_divide(1, fact)
C:\Users\Fred\Anaconda2\envs\PST\lib\site-packages\numpy\lib\function_base.py:2480: RuntimeWarning: inval
id value encountered in multiply
c *= np.true_divide(1, fact)
Traceback (most recent call last):
File "test_script_PSTme.py", line 168, in
eigvals, eigvecs = np.linalg.eigh(np.cov(ODhat.T))
File "<array_function internals>", line 6, in eigh
File "C:\Users\Fred\Anaconda2\envs\PST\lib\site-packages\numpy\linalg\linalg.py", line 1471, in eigh
w, vt = gufunc(a, signature=signature, extobj=extobj)
File "C:\Users\Fred\Anaconda2\envs\PST\lib\site-packages\numpy\linalg\linalg.py", line 94, in _raise_li
nalgerror_eigenvalues_nonconvergence
raise LinAlgError("Eigenvalues did not converge")
numpy.linalg.LinAlgError: Eigenvalues did not converge