No argmax returns the position of the largest value. max returns the largest value.
import numpy as np
A = np.matrix([[1,2,3,33],[4,5,6,66],[7,8,9,99]])
np.argmax(A) # 11, which is the position of 99
np.argmax(A[:,:]) # 11, which is the position of 99
np.argmax(A[:1]) # 3, which is the position of 33
np.argmax(A[:,2]) # 2, which is the position of 9
np.argmax(A[1:,2]) # 1, which is the position of 9