how to plot scipy optimize result

Question

I have python scipy optimize with function f(x) = sin(x) and I want to plot the result. how can I do that? I am already have try with this code. but I get this error: TypeError: only length-1 arrays can be converted to Python scalars

here it is my code :

'''Import Python math library'''
import math
import matplotlib.pyplot as plt
'''try and except ImportError handler will be printing message if you haven't install required python library'''
try:
    import scipy.optimize as opt
    import scipy
    from scipy.optimize import minimize
except ImportError:
    print "You must install Python scipy first before running this program"

try:
    import numpy as np
except ImportError:
    print "You must install Python numpy first before running this program"

'''function f(x) = sin(x)'''
def f(x):
    print x
    #return -x**(2)
    return math.sin(x)

'''
check here for fmin_l_bgfs_b docs : https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.fmin_l_bfgs_b.html#scipy.optimize.fmin_l_bfgs_b
and what params need to used.

or you can take a look at here : https://docs.scipy.org/doc/scipy/reference/optimize.html for other method and algorithm
'''
initial_guess = 1.0

minbound = -9
maxbound = 9

max_bounds_area = (minbound,maxbound)
max_x = opt.fmin_l_bfgs_b(lambda x: -f(x), initial_guess, bounds=[(max_bounds_area)],approx_grad=True)

# I want to plot the result. I try this but I get TypeError: only length-1 arrays can be converted to Python scalars
t = np.arange(minbound, maxbound, initial_guess)
s = f(t)
plt.plot(t, s)
plt.show()

eyllanesc · Accepted Answer · 2017-04-05 00:50:18Z

3

The math library can not operate on numpy arrays, you must use the functions implemented in numpy.

Must be change

return math.sin(x)

to

return np.sin(x)

answered Apr 5, 2017 at 0:50

eyllanesc

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4 Comments

Yuda Prawira Over a year ago

Thanks, it works. But how can I make it with smooth curve?

eyllanesc Over a year ago

Has smaller to initial_guess, is the step that is used to plot. ie initial_guess=0.1

Yuda Prawira Over a year ago

thanks it work with t = np.arange(minbound, maxbound, 0.1). really thanks I appreciate it.

Yuda Prawira Over a year ago

I need to wait it for 5 minutes to accept this as correct answer.

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