Thanks for the catch in the docstring. I've fixed that on the version of slsqp.py attached to the ticket. I'm not positive this is the correct minimum, but it definitely is trending towards this result when that error in encountered. This appears to be a case where SLSQP just can't quite zero in on the minimum. I know its a kludge, but lowering the requested accuracy to 1.0E-5yields a converged solution, within 3 or 4 decimal places of what appears to be the true minimum. Does this appear to be yielding proper results? from numpy import * from scipy.optimize.slsqp import fmin_slsqp N = 10 M = 5 ff = lambda x: (abs(x-M) ** 1.5).sum() x0 = cos(arange(N)) print "Initial guess", x0 c = lambda x: asfarray([2* x[0] **4-32, x[1]**2+x[2]**2 - 8]) h1 = lambda x: 1e1*(x[-1]-1)**4 h2 = lambda x: (x[-2]-1.5)**4 #TODO: pass bounds to fmin_slsqp when all other will work ok bounds = [(-6,6)]*10 bounds[3] = (5.5, 6) #bounds[4] = (6, 4.5) diffInt = 1e-8 # Unconstrained print "Unconstrainted" x = fmin_slsqp( ff, x0, epsilon = diffInt, bounds=bounds, iprint=1, acc= 1.0E-12) print x print "\n" # Inequality constraints print "Inequality constraints" x = fmin_slsqp( ff, x0, epsilon = diffInt, iprint=1, acc=1.0E-12, f_ieqcons = c, bounds=bounds ) print x print "\n" h1 = lambda x: 1e1*(x[-1]-1)**4 h2 = lambda x: (x[-2]-1.5)**4 # Inequality and Equality constraints print "Inequality and Equality constraints" x = fmin_slsqp( ff, x0, epsilon = diffInt, iprint=1, acc=1.0E-12, f_eqcons=lambda x: asfarray([h1(x), h2(x)]), f_ieqcons = c, bounds=bounds ) print "Solution vector", x print "Equality constraint values:",h1(x), h2(x) print "Inequality constraint values:", c(x) print "\n" # Inequality and Equality constraints - lower requested accuracy print "Inequality and Equality constraints - lower requested accuracy" x = fmin_slsqp( ff, x0, epsilon = diffInt, iprint=1, acc=1.0E-5, f_eqcons=lambda x: asfarray([h1(x), h2(x)]), f_ieqcons = c, bounds=bounds ) print "Solution vector", x print "Equality constraint values:",h1(x), h2(x) print "Inequality constraint values:", c(x) -- - Rob Falck