I am converting some MATLAB code in to python and have the encountered the error "ValueError Traceback (most recent call last) in 1 for ig in range(nbas): ----> 2 psi[:,ig] = np.polyval(np.array(pp[ig,:ig]),nodes)

ValueError: could not broadcast input array from shape (56,1) into shape (56) " I cannot find the issue with following code:

import numpy as np
import scipy.special as scl

##basis parameters (nbas<ngrid+1)
nbas = 54 #Basis set size in one dimension
ngrid = 56 #quadrature size

#Hermite matrix
def hermipol(n):
    p = np.zeros((n+1,n+1))
    p[0][0] = 1
    if n == 0:
        p = np.array([[1,0],[2,0]], dtype = float)
    if n > 0:
        p[1][range(0,2)] = np.array([2,0])
        if n >=1:
            for k in range(2,n+1):
                p[k][range(n)] = 2*p[k-1][range(0,n)]
                p[k][range(2,n+1)] += -2*(k-1)*p[k-2][range(0,n-1)]
    for i in range(0,n+1):
        p[i,:] /= np.sqrt(np.sqrt(np.pi)*2**(i)*scl.factorial(i))

#Generation Gauss-Hermite Quadrature nodes and weights
def ghquad(n):
[nodes,weights]  = ghquad(ngrid)

pp = hermipol(ngrid)

#Evaluation and store psi_i()(x,y)_k)
nodes = np.array([nodes]).T
weights = np.array([weights]).T
psi = np.zeros((ngrid,nbas))

for ig in range(nbas):
    psi[:,ig] = np.polyval(np.array(pp[ig,:ig]),nodes)

Any guidance would be greatly appreciated.



This post is better suited for Stackoverflow I think. Anyway you can simply solve your problem by changing psi[:,ig]to psi[:,ig:ig+1]. Then the left-hand side is truly a nx1 matrix, not just a vector of size n.

Or you can remove the line nodes = np.array([nodes]).T which is useless here, and causes Numpy to transform the array "nodes" (size n), into a 1xn array. Then the original psi[:,ig] works.

This kind of shape issue should easily be debugged by hand though !

  • $\begingroup$ Solved, thanks for the response! when I post questions in the future I will use the over. $\endgroup$
    – New2Python
    Nov 25 '20 at 18:02

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