what is the problem with this?

starting_num = SOME_NUMBER
while True:
    for i in xrange(starting_num, len(array)):
        # do code
    starting_num = 0

it does exactly what you want.

however, i think there are better ways to do things especially if the solution seems "hacky".

if you gave an idea of what you wanted to do, maybe there is a better way

You do not need the x=i and i=x+i inside your loop.

for i in range(0, 50):
    print(i)

would work just fine and would output 0,1,2,3...47,48,49. i is being set according to the range(0,50). If you want i to start at 1 simply change the range to range(1,50). Your code also added 1 to each i value so in order to account for this in the range you would need to do range(1,51) which would print 1,2,3...48,49,50.

Further Reading

I would recommend reading these to better understand how for loops work and also more info about ranges:

Range()

For Loops

Just change the function

def create_m_(y, m, theta, mc, theta_mc)

to:

def create_m_(y, m, theta, mc=initial_value, theta_mc=initial_value)

When you call this function for the first time without specifying the value of mc or theta-mc, they will default to the initial value.

The for index in range(len(list)) loop executes the loop body with index first set to 0, then 1, then 2, etc. up to len(list) - 1. The previous value of index is ignored and overwritten. If you want index to start at iteration + 1, use the 2-argument form of range:

for index in range(iteration + 1, len(list)):

Straightforward way is following:

def funct_1(x):
    y = x + 1
    return y


def funct_2(y):
    z = y + 1
    return z


def main(x):
    y = funct_1(x)
    z = funct_2(y)
    return z


state = 40
for i in range(10):
    state = main(state)