numpy.vander() function | Python

numpy.vander() function is used to generate a Vandermonde matrix.

Syntax : numpy.vander(arr, N = None, increasing = False) Parameters : arr : [ array_like] 1-D input array. N : [int, optional] Number of columns in the output. If N is not specified, a square array is returned (N = len(x)). increasing : [bool, optional] Order of the powers of the columns. If True, the powers increase from left to right, if False (the default) they are reversed. Return : [ndarray] dVandermonde matrix. If increasing is False, the first column is x^(N-1), the second x^(N-2) and so forth. If increasing is True, the columns are x^0, x^1, ..., x^(N-1).

Code #1 : Output :

[[ 1 1 1 1 1]
 [ 16 8 4 2 1]
 [ 81 27 9 3 1]
 [256 64 16 4 1]
 [625 125 25 5 1]]

  Code #2 : Output :

[[ 1 1 1]
 [ 4 2 1]
 [ 9 3 1]
 [16 4 1]
 [25 5 1]]

  Code #3 : Output :

[[ 1 1 1 1 1]
 [ 1 2 4 8 16]
 [ 1 3 9 27 81]
 [ 1 4 16 64 256]
 [ 1 5 25 125 625]]