python code to compute spherical harmonics

sh.py

import numpy as np

sh = np.zeros(9)
sh[0] = 1 / np.sqrt(4 * np.pi)
sh[1:4] = 2 * np.pi / 3 * np.sqrt(3 / (4 * np.pi))
sh[4] = np.pi / 8 * np.sqrt(5 / (4 * np.pi))
sh[5:8] = 3 * np.pi / 4 * np.sqrt(5 / (12 * np.pi))
sh[8] = 3 * np.pi / 8 * np.sqrt(5 / (12 * np.pi))

def calc_sh_light(x, y, z):
  res = np.zeros(9)
  res[0] = sh[0];
  res[1] = sh[1] * z;
  res[2] = sh[2] * y;
  res[3] = sh[3] * x;
  res[4] = sh[4] * (2 * z * z - x * x - y * y);
  res[5] = sh[5] * y * z;
  res[6] = sh[6] * x * z;
  res[7] = sh[7] * x * y;
  res[8] = sh[8] * (x * x - y * y);
  return res