[FIXED] Python creating multiple array from a basis array

Issue

Given an array [x1 x2 x3 ... xn] containing n elements, it is desired to produce such following array containing K rows:

[[x1   x2   x3   ... xn],
 [x1^2 x2^2 x3^2 ... xn^2],
 [x1^3 x2^3 x3^3 ... xn^3],
 ...,
 [x1^K x2^K x3^K ... xn^K]].

How to get this efficiently ?

Solution

A variation on the power.outer using the ** operator and broadcasting:

In [223]: np.arange(1,5)**np.arange(1,4)[:,None]                                
Out[223]: 
array([[ 1,  2,  3,  4],
       [ 1,  4,  9, 16],
       [ 1,  8, 27, 64]])

Answered By - hpaulj