NameError: global name 'x' is not defined

[Geared]

Hello I'm new to python (been using it all of 2 weeks) and I'm trying to write a program that compares the result of an equation using two different starting numbers that the user chooses. It also lets the user choose how many time it preforms the function and the amplitude of the function [a * x * (1 - x)]. here is the code. I'm using Vista 64 bit and Python v2.62.

def compare():
    for i in range(num_iterations):
            A = A * a * (1 - A)
        B = B * a * (1 - B)
    print A, B
    def main():
        a = input ("Enter the amplitude: ")
        num_interations = input ("Enter the number of interations: ")
        A = input ("Enter the starting value for the A series: ")
        B = input ("Enter the starting value for the A series: ")
    compare()

I keep getting the error:

Traceback (most recent call last):
File "<pyshell#46>", line 1, in <module>
compare()
File "<pyshell#45>", line 2, in compare
for i in range(num_iterations):
NameError: global name 'num_iterations' is not defined

Any help would be appreciated. Thanks!

[bvdet]

Please use code tags when posting code.

It's a matter of scope. You can learn about Python scope rules here. Add arguments to function compare, and pass the input from the user to the function. Your function definition main() is indented incorrectly.

def compare(n, a, A, B):
    for i in range(n):
        A *= a * (1 - A)
        B *= a * (1 - B)
    print A, B
 
def main():
    a = input ("Enter the amplitude: ")
    num_interations = input("Enter the number of interations: ")
    A = input("Enter the starting value for the A series: ")
    B = input("Enter the starting value for the B series: ")
    compare(num_interations, a, A, B)
 
if __name__ == '__main__':
    main()

[Geared]

Thanks for the help. That fixed it.