Factor analysis;parameter estimation

How to use Pymc for factor analysis? I found the examples provided in the Pymc documentation, but after running the case code, I did not get the running results in the case.The estimated values of all elements in the load matrix will approach zero.Why is this? Is there a comparative significance between the factor model parameters estimated through the constraints imposed in the case and the parameters estimated using principal component methods/maximum likelihood methods.
Factor analysis — PyMC example gallery