title: Markov Chain Monte Carlo (python, numpy)
body: <p>I am doing some research in physics, for which I need to analyze some data using a Markov Chain Monte Carlo (MCMC).  I tried to just write one myself but I keep coming across bugs when python/numpy rounds a very very small number down to zero.  Specifially when I need to do something like <code>numpy.exp(-1000)</code>.  That expression itself is part of a larger math equation so I can't just take the log of it.  </p>
  
  <p>I know that there are MCMC modules available for python and I have taken a look at some of them but am having trouble understanding the documentation for them to apply them.  Can anyone recommend one?  What I have is a column of data that I plug into a probability distribution. This distribution also has two other variables which I will be conducting random walks on and recording each step in the markov chain.  I will then need to make a histogram of each of those two variables based off the markov chain. I apologize if this question is too vague.  Any ideas or suggestions are much appreciated, thanks!</p>