https://numpy.org/devdocs/reference/generated/numpy.array.html

https://courspython.com/fonctions-mathematiques-numpy.html

flatten : 
import numpy as np
a = np.array([[1,2], [3,4]])
a.flatten()
array([1, 2, 3, 4])
a.flatten('F')
array([1, 3, 2, 4])
https://numpy.org/devdocs/reference/generated/numpy.ndarray.flatten.html