Keep Running into "TypeError: 'numpy.float64' object is not callable"

Question

I keep getting the error

TypeError: 'numpy.float64' object is not callable"

I thought I have been careful to not repeat variables within functions etc., but this error keeps popping up whenever I try to execute

scipy.integrate.odeint(doublepend,fnaught,t,args=(L,9.81,M))

I'm not sure what's going on. See below for the rest of the code.

import scipy as scipy
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import math as mt
import numpy as np

def singlepend(thetarray,time,Length,gravity,mass):
    import numpy as np

    theta,delatheta=y
    dtheta=np.zeros_like(y)
    #theta solved
    dtheta[0]=deltatheta
    dtheta[1]=(g/L)*np.sin(theta)
    return dy

def doublepend(y,tim,Langles,g,Mangles):

    import numpy as np

    thetanaught,deltatheta,phinaught,deltaphi=y
    mtheta,mphi=Mangles
    print mtheta
    Ltheta,Lphi=Langles
    dy=np.zeros_like(y)
    #theta solved
    dy[0]=deltatheta
    dy[1]=-mphi*np.sin(thetanaught-phinaught)*((deltatheta**2)*np.cos(thetanaught-phinaught)+(deltaphi**2)*Lphi/Lphi)/(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos(thetanaught-phinaught)))\
    +mphi*g*np.sin(phinaught)*np.cos(thetanaught-phinaught)/(Ltheta*(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos(thetanaught-phinaught))))\
    -(mtheta+mphi)*g*np.sin(thetanaught)/(Ltheta*(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos(thetanaught-phinaught))))
    #phi solved
    dy[2]=deltaphi
    dy[3]=mphi*(deltaphi**2)*np.sin(thetanaught-phinaught)/(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos(thetanaught-phinaught)))\
    +(mtheta+mphi)*g*np.sin(thetanaught)*np.cos(thetanaught-phinaught)/(Lphi*(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos(thetanaught-phinaught))))\
    (mtheta+mphi)*Ltheta*(deltatheta**2)*np.sin(thetanaught-phinaught)/(Lphi*(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos*(thetanaught-phinaught))))\
    -(mtheta+mphi)*g*np.sin(phinaught)/(Lphi*(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos(thetanaught-phinaught))))

    return dy



#initial conditions
m1=1
m2=1
L1=1
L2=1

M=(m1,m2)
L=(L1,L2)
phi1naught=np.array(np.pi/2)
phi2naught=np.array(np.pi/2)
phi1dotnaught=np.array(0)
phi2dotnaught=np.array(0)

fnaught=(phi1naught,phi1dotnaught,phi2naught,phi2dotnaught)


t=np.linspace(0,20,100001)

f=scipy.integrate.odeint(doublepend,fnaught,t,args=(L,9.81,M))

I realize that I do not need to import numpy multiple times. I am designing those functions to become a small library of functions to be used later as examples.

Answer 1

We need to see some of the stack, but even with that it may be hard to identify which variable is giving problems.

The error means that some code is trying to do something like x(args), i.e. use x as a function. But contrary to expectations x is a number, not a function.

The solution is to identify what variable is causing the problem, and trace that back to your code.

Offhand the inputs to odeint look fine:

odeint(doublepend,fnaught,t,args=(L,9.81,M))

Of these only the first, doublepend has to be a function. It appears to be that, but I'd couple check just before the odeint call.

fnaught is the initial condition. You appear to create a tuple of values. I'd make an array, but I think odeint will do that automatically.

t is an array

args gets a tuple of numbers. Those get passed to your doublepend.

Does doublepend(fnaught, 0, L, 9.81, M) run? What does it return?

The other answer thinks the problem lies in that doublepend function. A stack trace would make that clear, as would the above test calc.

---

In [13]: doublepend(fnaught, 0, L, 9.81, M)
1
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-13-f8aa70c3f962> in <module>()
----> 1 doublepend(fnaught, 0, L, 9.81, M)

<ipython-input-10-3c95347f392b> in doublepend(y, tim, Langles, g, Mangles)
     13     #phi solved
     14     dy[2]=deltaphi
---> 15     dy[3]=mphi*(deltaphi**2)*np.sin(thetanaught-phinaught)/(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos(thetanaught-phinaught)))    +(mtheta+mphi)*g*np.sin(thetanaught)*np.cos(thetanaught-phinaught)/(Lphi*(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos(thetanaught-phinaught))))    (mtheta+mphi)*Ltheta*(deltatheta**2)*np.sin(thetanaught-phinaught)/(Lphi*(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos*(thetanaught-phinaught))))    -(mtheta+mphi)*g*np.sin(phinaught)/(Lphi*(mtheta+mphi*(1-np.cos(thetanaught-phinaught)*np.cos(thetanaught-phinaught))))
     16 
     17     return dy

TypeError: 'numpy.float64' object is not callable

OK - the error is somewhere in that long and ugly dy[3] expression. Break it up, and figure out where you are using () for something that is a number rather than function.

This looks suspicious

np.cos(thetanaught-phinaught))))   (mtheta+mphi)

np.cos() evaluates to a number, and the next (methata...)looks like an function call. It runs if I delete the last 2 lines of dy[3]. Something is missing at that line continuation`.