Multiplying a float Number to a Function in Python and getting can't multiply sequence by non-int of type 'float'

Question

I have the following code written in python 2.7. Here I've defined two function, a cosine function and an exponential function and I need to multiply these functions to a float Value, but I am getting this error. I assume we can't multiply a float value to a function in list() format... I would be grateful if someone tell me how can I do this. Thanks in advance. Here is my code :

import numpy as np
import math
import cmath

delta  = 2.0*math.pi*1.46*((1.0/1530)-(1.0/1550))

#defining main func
def apFunc(x):
    return np.exp(-4*math.log(2)*((x-(5/2))/5)**2)*(1+math.cos((2*math.pi/0.001)*x))
Domain = list(np.arange(0,5,0.001))
APF    = map(apFunc,Domain)

#defining modulation function 
def modFunc(x):
    return (1+math.cos((2*math.pi/0.001)*x))
d      = list(np.arange(0,5,0.001))
mod    = map(modFunc,d)

#making sig and kaa functions
sgima  = (2*math.pi/1530)*APF
sig    = sigma + delta
kaa    = (math.pi/l1530)*mod
gamma  = math.sqrt(sig**2 + kaa**2)

Answer 1

Sticking to NumPy (and specifically avoiding math/cmath altogether) would just solve the issues you are observing, by completely avoiding non-broadcast-friendly containers / operations:

import numpy as np


delta = 2.0 * np.pi * 1.46 * ((1.0 / 1530) - (1.0 / 1550))


def apFunc(x):
    return np.exp(-4 * np.log(2) * ((x - (5 / 2)) / 5) ** 2) * (
        1 + np.cos((2 * np.pi / 0.001) * x)
    )


def modFunc(x):
    return 1 + np.cos((2 * np.pi / 0.001) * x)


d = np.linspace(0.0, 5.0, 5000)
APF = apFunc(d)
mod = modFunc(d)

# making sig and kaa functions
sigma = (2 * np.pi / 1530) * APF
sig = sigma + delta
kaa = (np.pi / 1530) * mod
gamma = np.sqrt(sig ** 2 + kaa ** 2)

(I also fixed some typos here and there, and cleaned/reordered a little bit, although it is not yet fully PEP8-compliant)

Note that I have replaced the use of np.arange() with an equivalent call to np.linspace(), since as-per its documentation: "When using a non-integer step, such as 0.1, the results will often not be consistent. It is better to use numpy.linspace for these cases."

Answer 2

whoo, lots in there.

Friendly tip- providing the stack trace makes it easier to help you, as would reducing the code to just the important parts.

For your actual problem -

mod is map(modFunc,d)

map returns a list so mod = [..., ...] then kaa = (pi) * mod

or (pi) * [..., ...]

Which doesn't make much sense. You probably want a map there as well?