Issue computing Hessian with Foward mode

[Gustavo Chaparro]

Hey! I am beginner using python from scientific computation and I am just discovering the capabilities of Algopy (such a great work btw).

So far I am having some issues when computing the Hessian of a scalar function with the forward mode, thi is my code so far:

import numpy as np
import algopy
from algopy import UTPM

g12, g21, g13, g31, g23,g32
g=np.array([1337.69,-235.61,1456.94,998.39,-935.27,680.02])
g12,g21,g13,g31,g23,g32=g
A=np.array([[0,g12,g13],[g21,0,g23],[g31,g32,0]])
#α12,13,32
α=0.2
T=313.15

def NRTL(X0,T):
    x1,x2=X0
    X=np.array([x1,x2,1-x1-x2])
    τ=A/T
    G=np.exp(-α*τ)
    P1=np.sum(X*τ.T*G.T,1)/np.sum(X*G.T,1)
    P2=X*G/np.sum(X*G.T,1)
    P3=τ-P1
    lnγ=np.sum(P3*P2,1)+P1
    Gex=np.sum(X*lnγ)
    return Gex

X=np.array([0.3,0.4])
#algopy
x = UTPM.init_hessian(X)
y = NRTL(x,T)
algopy_jacobian = UTPM.extract_hessian(2,y)

I keep getting the following error: 

TypeError: 'float' object cannot be interpreted as an integer

I also tried with some of the examples on the documentation (https://pythonhosted.org/algopy/examples/ampl_minimization_problem.html,

 https://pythonhosted.org/algopy/examples/hessian_of_potential_function.html) and I got the same error. 

When I use the reverse mode everything is working properly.

do you any suggestions?

Thanks in advance!

Gustavo.

[Sebastian Walter]

I can't reproduce the issue. After replacing the greek unicode symbosl to ASCII tau, gamma and alpha, the code seems to work fine.

What version of Algopy and Python do you use?

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[Gustavo Chaparro]

Thanks for replying!

Python: 3.6.3

Numpy version:  1.13.3

Scipy: 0.19.1

Algopy: 0.5.3

I tried changing greek letters and still the same :/

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