I am wondering if it is possible to compute the greatest common divisor for more than 2 arrays using numpy.gcd(). Using the following arrays for x, y, z:
import numpy as np
x = np.array([[4,6,28],[2,5,6]])
y = np.array([[2,1,7],[7,23,6]])
z = np.array([[3,0,4],[7,4,3]])
Here the gcd code taking the 3 arrays:
result = np.gcd(x,y,z)
Which leads to:
array([[2, 1, 7],
[1, 1, 6]])
result[0,2]
7
Instead of 7 shouldn't this be 1? Given the numbers 28, 7, 4, the following returns 1.
numpy.gcd.reduce([28, 7, 4])
So my question is if I am making a mistake at some point, or is numpy.gcd not capable of taking as input 3 arrays and simply computing the gcd over the first two arrays it receives as input?
From https://numpy.org/doc/stable/reference/generated/numpy.gcd.html
The function signature is this:
def numpy.gcd(x1, x2, /, out=None, *, ...):
If you call gcd with three arguments, you are basically doing z = gcd(x, y). Therefore you need to come up with your own function. It could be something like
def my_gcd(x, y, z):
return np.gcd(np.gcd(x, y), z)
which would return
[[1 1 1]
[1 1 3]]