Thank you for your reply.
I recieved the following warning
C:\Users\GTS\anaconda3\envs\pymc_env\Lib\site-packages\pymc\sampling\mcmc.py:243: UserWarning: Use of external NUTS sampler is still experimental
warnings.warn("Use of external NUTS sampler is still experimental", UserWarning)
Does the warning means that the sampler is not efficient or accurate?