How to calculate integral value?

[Tli_You]

I am getting an IndexError, and not sure why? My goal is to calculate the Following integral.
the mathematical expression in attached file

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%reset -f import numpy as np from scipy import io, integrate, linalg, signal from scipy.sparse.linalg import cg, eigs import sympy as sp import math from math import * from sympy import  * # Define symbols z = sp.symbols('z') lh = 10. L = 1. h = L / lh p = 10. V = ((1. / 2.) + (z / h))**p Ec = 380. vc = 0.23 Em = 70. vm = 0.23 # Effective properties of the CNTRC Ez = Em + (Ec - Em) * V fz=z; fz1=diff(fz,z); Q11=Ez; Q55=Ez/(2*(1+vm)); B11=sp.integrate(Q11*z,(z,-h/2,h/2));

Error:
TypeError: 'Float' object cannot be interpreted as an integer

your help is appreciated

[Larz60+]

Please elaborate, at least, please:

• What is the error (please post entire error traceback massage using bbcode error tags).
  
• Show the mathematical expression, in the text.
  

[Pedroski55]

Long time since I did any maths!

Don't know how to put maths symbols here, so I will use S as the integral symbol.

I seem to remember you can just take the Q out, calculate the result and multiply the result by Q, but I'm not so sure of that.

The definite integral Sxdx between the limits a and b, using Python power symbol ** is very simple:

(b**2) / 2 - (a**2) / 2

For example:

a = 0, b=2, Q=3

S 3xdx = 3((2**2) / 2) =6

You don't need any modules for any given Q, z

[Tli_You]

Dear Pedroski5, thanks for the replying.
Could you please explain in more with a python example

[Pedroski55]

Like I said, my maths is a bit rusty, but something like this should do it:

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# Python uses x**n to mean x to the power of n # the Definite Integral of x**ndx between a and b is defined as： # (b**(n+1)) / (n+1) - (a**(n+1)) / (n+1) # Let S represent the integration symbol # result = S Qzdz   # a function to calculate the Definite Integral def calculateDefInt(Q, a, b, n):     res = Q * ((b**(n+1)) / (n+1)) - ((a**(n+1)) / (n+1))     return res   # first collect the values as a list # append the values as a float type value values = [] for v in 'Qabn':     value = input(f'Enter a value for {v} ... ')     values.append(float(value))   DefInt = calculateDefInt(*values)

If

Output:
values = [3.0, 0.0, 2.0, 1.0]

then

Output:
calculateDefInt(*values) = 6.0

[Tli_You]

Hi
[SOLVED]

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from scipy.integrate import trapz import numpy as np import sympy as sp from sympy import  * from sympy import symbols # Define symbols z = symbols('z') Ec=380;Em=70;L=1.; lh =10. p=10. h=L/lh V = ((1. / 2.) + (z / h))**p Ez=(Ec-Em)*V+Em Q11=Ez; zz = np.linspace(-h/2, h/2, 600) # Substitute zz into the symbolic expression Q11 B11_vals = [(z*Q11).subs(z, val) for val in zz] # Perform numerical integration B11 = np.trapz(B11_vals, zz) print(f'B11={B11:4.6f}')