Hello, I am not sure whether this is a place to write about it (but I did not manage to file a ticket to truc so here it is). I found a little bug in scipy.optimize.slsqp.py(line 265): for i in range(len(bounds)): if bounds[i][0] > bounds[i][1]: raise ValueError('SLSQP Error: lb > ub in bounds[' + str(i) + '] ' + str(bounds[4])) ------ but should be: for i in range(len(bounds)): if bounds[i][0] > bounds[i][1]: raise ValueError('SLSQP Error: lb > ub in bounds[' + str(i) + '] ' + str(bounds[i])) -- Oleksandr Huziy