TypeError: unsupported operand type(s) for ^: 'numpy.float64' and 'numpy.float64'

Question

I just started programming in Python and am very new to Numpy packages... I'm still trying to get a hang of it. I am trying to slove a function with the euler method.

Here is my code:

Z=4
B=8
U=1
C=4

a,b=(0.0,10.0)
n=2000
x0=-1.0
t=linspace (a,b,n)
#-----------------------------------------------------------------------------
def euler (f,x0,t):
    n=len (t)
    x=np.array(n*[x0,])
    for i in xrange (n-1):
        float (x[i] + ( t[i+1] - t[i] ) * f( x[i], t[i] ))
    return x



#---------------------------------------------------------------------------------          
if __name__=="__main__":


    def f(x,t): 
        return float((Z)*[-(1/6)*B*C*x^3+0.5*U*t^2])


    #numerical solutions
    x_euler=euler(f,x0,t)


    #figure
    plt.plot (t,x_euler, "b")
    xlabel (t)
    ylabel (x)
    legend ("Euler")

    show()

I do not get along with the similar solutions for such problems. Here is my Traceback:

Traceback (most recent call last):
  File "C:\Python27\testeuler.py", line 45, in <module>
    x_euler=euler(f,x0,t)
  File "C:\Python27\testeuler.py", line 31, in euler
    float (x[i] + ( t[i+1] - t[i] ) * f( x[i], t[i] ))
  File "C:\Python27\testeuler.py", line 41, in f
    return float((Z)*[-(1/6)*B*C*x^3+0.5*U*t^2])
TypeError: unsupported operand type(s) for ^: 'numpy.float64' and 'numpy.float64'

Anyone know what could be wrong or have any suggestions?

Solution

The caret operator (^) is not exponentiation. It is bitwise XOR, which only makes sense for integers. You want ** instead.