Understanding argmax

Question

Let say I have the matrix

import numpy as np    
A = np.matrix([[1,2,3,33],[4,5,6,66],[7,8,9,99]])

I am trying to understand the function a

Answer 1

In my first steps in python i have tested this function. And the result with this example clarified me how works argmax.

Example:

# Generating 2D array for input 
array = np.arange(20).reshape(4, 5) 
array[1][2] = 25

print("The input array: \n", array) 

# without axis
print("\nThe max element: ", np.argmax(array))
# with axis
print("\nThe indices of max element: ", np.argmax(array, axis=0)) 
print("\nThe indices of max element: ", np.argmax(array, axis=1)) 

Result Example:

The input array: 
[[ 0  1  2  3  4]
[ 5  6 25  8  9]
[10 11 12 13 14]
[15 16 17 18 19]]

The max element:  7

The indices of max element:  [3 3 1 3 3]

The indices of max element:  [4 2 4 4]

In that result we can see 3 results.

1. The highest element in all array is in position 7.
2. The highest element in every column is in the last row which index is 3, except on third column where the highest value is in row number two which index is 1.
3. The highest element in every row is in the last column which index is 4, except on second row where the highest value is in third columen which index is 2.

Reference: https://www.crazygeeks.org/numpy-argmax-in-python/

I hope that it helps.