You can find closed-form expressions for SOME likelihood functions. This is the case for logistic regression. Anyway, the takeaway that I think you were downvo

You can find closed-form expressions for SOME likelihood functions. This is the case for logistic regression. Anyway, the takeaway that I think you were downvoted for omitting is that if you can bypass the serialization, startup, and shutdown steps associated with the traditional Hadoop iterative process you'll get a huge speedup.