I'm trying to use scipy.optimize.minimize. I've tried multiple "multivariate" methods that don't seem to actually take multivariate data and derivatives. Can someone tell me how I can make the multivariate part of the solver actually work? Here's an example: My main function the following (typical length for N is 3): input guess is a x0=np.array([1,2,3]) the optimization function returns: def calc_f3d(...): f3d = np.ones((np.max([3,N]),1) .... do some assignments to f3d[row,0] .... return np.linalg.norm(f3d) # numpy.array that's 3x1 The jacobian returns a Nx3 matrix: def jacob3d(...): df = np.ones((np.max([3,N]),3)) ... do some assignments to df[row,col] return df # note numpy.array that's 3x3 The optimize call is: OptimizeResult = optimize.minimize( fun=tdcalc.calc_f3d, x0=ract, jac=tdcalc.jacob3d, method='BFGS', args=(operdata,), tol=1.0e-8, options={'maxiter': 40000, 'xtol':1e-8}) <--- ops change based on whether using Newton-CG or BFGS When I use BFGS, I get: Traceback (most recent call last): File "./tdoa_calc.py", line 664, in <module> options={'maxiter': 40000, 'gtol':1e-8}) File "/usr/lib64/python2.7/site-packages/scipy/optimize/_minimize.py", line 348, in minimize return _minimize_bfgs(fun, x0, args, jac, callback, **options) File "/usr/lib64/python2.7/site-packages/scipy/optimize/optimize.py", line 779, in _minimize_bfgs old_fval, old_old_fval) File "/usr/lib64/python2.7/site-packages/scipy/optimize/linesearch.py", line 95, in line_search_wolfe1 c1=c1, c2=c2, amax=amax, amin=amin, xtol=xtol) File "/usr/lib64/python2.7/site-packages/scipy/optimize/linesearch.py", line 147, in scalar_search_wolfe1 alpha1 = min(1.0, 1.01*2*(phi0 - old_phi0)/derphi0) ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all() When I use Newton-CG, I get: Traceback (most recent call last): File "./tdoa_calc.py", line 655, in <module> options={'maxiter': 40000, 'xtol':1e-8}) File "/usr/lib64/python2.7/site-packages/scipy/optimize/_minimize.py", line 351, in minimize **options) File "/usr/lib64/python2.7/site-packages/scipy/optimize/optimize.py", line 1320, in _minimize_newtoncg eta = numpy.min([0.5, numpy.sqrt(maggrad)]) File "/usr/lib64/python2.7/site-packages/numpy/core/fromnumeric.py", line 1982, in amin out=out, keepdims=keepdims) File "/usr/lib64/python2.7/site-packages/numpy/core/_methods.py", line 14, in _amin out=out, keepdims=keepdims) ValueError: setting an array element with a sequence.