I have a situation where scipy.optimize.minimize returns the initial starting value as the answer without really iterating, and returns "successful" status, using default method. It works fine if I specify Nelder-Mead, but my question is "why does minimize return successful when it isn's, and what can I do (if anything) to flag this behavior? The question is also here http://stackoverflow.com/q/36110998 and if someone can also leave an answer there as well, that would be great! but not necessary. One particular - I'm using calls to Skyfield, which may or may not have something to do with it. (http://rhodesmill.org/skyfield/) FULL OUTPUT using DEFAULT METHOD: status: 0 success: True njev: 1 nfev: 3 hess_inv: array([[1]]) fun: 1694.98753895812 x: array([ 10000.]) message: 'Optimization terminated successfully.' jac: array([ 0.]) nit: 0 FULL OUTPUT using Nelder-Mead METHOD: status: 0 nfev: 63 success: True fun: 3.2179306044608054 x: array([ 13053.81011963]) message: 'Optimization terminated successfully.' nit: 28