The dot and Cross product from numpy are not returning the expected values

Question

I'm trying to code a function that will rotate a vector around an axis by an angle. Though I am running into some problems.I will show the trouble-shooting code I wrote.

import numpy as np

def unit_vector(vec):
    vec = np.array(vec, float)
    unit_vec = []
    for i in range(len(vec)):
        unit_vec.append(vec[i]/np.linalg.norm(vec))
    return np.array(unit_vec, float)


def rotation(vector,axis, angle):
    vector = np.array(vector, float)
    axis = np.array(vector, float)
    first  = vector * np.cos(angle)
    second = np.cross(vector, unit_vector(axis))
    third = unit_vector(axis)
    fourth = np.dot(vector, unit_vector(axis))
    fifth = 1 - np.cos(angle)
    print("first : {0} \nSecond : {1} \nThird : {2}\nFourth : {3}\nFifth : {4}\n ".format(list(first), list(second), list(third),fourth, fifth))

rotation([0,1,0],[0,0,1],np.pi/2)

Here is the output of my program :

first : [0.0, 6.123233995736766e-17, 0.0]
Second : [0.0, 0.0, 0.0]
Third : [0.0, 1.0, 0.0]
Fourth : 1.0
Fifth : 0.9999999999999999

I was wondering why the second and fourth values are [0,0,0] and 1 respectively. They should only output these values if the vector and the axis are both facing in the same direction (which they are not). Even when I print these variables outside of the function they output correctly. What is causing the program to get the second and fourth variables wrong?

Answer 1

In the second line of the rotation procedure. axis has been set to np.array(vector,float) and not np.array( axis, float.