Error in using Sympy in newton Raphson

[Swadhin Satapathy]

I got the following error: 

  File "C:\Users\Admin\.spyder-py3\temp.py", line 22, in <module>

    a = newton(p, p_prime,-10, 0)

  File "C:\Users\Admin\.spyder-py3\temp.py", line 15, in newton

    delta = p(x)/p_prime(x)

TypeError: 'Add' object is not callable

 While running the following code: 

import numpy as np

import matplotlib.pyplot as plt

import sympy as sym

acc = 1E-10

x = sym.Symbol('x')

def p(x): #define the function

    return 924*x**6 - 2772*x**5 + 3150*x**4 - 1680*x**3 + 420*x**2 - 42*x + 1

p_prime = sym.diff(p(x))

print(p_prime)

def newton(p,p_prime, acc, start_val):

    x= start_val

    delta = p(x)/p_prime(x)

    while abs(delta) > acc:

        delta = p(x)/p_prime(x)

        print(abs(delta))

        x =x- delta;

    return round(x, acc);

a = newton(p, p_prime,-10, 0)

[David Bailey]

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Try adding this line immediately before your line 15:

    print("p=",p,"  p_prime=",p_prime)

If you do that, you will see that p is a function - so it is OK to call it as in p(x),

however p_prime is an expression (an Add object, since it consists of a number of terms added/subtracted together), so it isn't OK to call it as in p_prime(x).

Hence your error message!

TypeError: 'Add' object is not callable

That error message is super obscure, it would be good to see it upgraded.

Cheers,

David

[Swadhin Satapathy]

Thanks, David, I realized that and solved it. Thanks for the heads-up.