ValueError: setting an array element with a sequence. scipy minimize [closed]

Question

""" ___ """
from scipy.optimize import minimize
import numpy as np


LENGTH = 100

def process(x):
    return x * 2 + 5

def draw(process, length):
    """ """
    y = np.random.normal(0, 10, length)
    data = [process(y_) for y_ in y]
    rnd = np.random.normal(3, 1, len(data))
    return y, rnd + data


def maximum_likelyhood(y, X):
    objective = lambda b: np.transpose(X) * (y - X * b)
    x0 = np.zeros(100)
    res =  minimize(objective, x0=x0)
    return res.x

y, X = draw(process, LENGTH)
print maximum_likelyhood(y, X)

produces a

ValueError: setting an array element with a sequence.

There is several similar problems, they all point out that x0 is not a 1D array, but here it is a 1D array. (or not? in case please explain why and how to make it 1D)

user1767344 · Accepted Answer · 2012-11-08 00:10:24Z

5

The error occurs because the objective function is a vector function (takes in a vector, returns a vector) but according to scipy.optimize.minimize documentation it only takes scalar function (takes a vector returns a scalar.)

answered Nov 8, 2012 at 0:10

user1767344

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1 Comment

Covich Over a year ago

Have a look on the scipy.optimize.root function, not the scipy.optimize.minimize one

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