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- # -*- coding: utf-8 -*-
- """
- Created on Wed Nov 10 23:33:33 2021
- @author: arefk
- """
- from __future__ import print_function # print('me') instead of print 'me'
- from __future__ import division # 1/2 == 0.5, not 0
- # - import common modules
- import numpy as np # the Python array package
- def mutualInfo(Im1,Im2):
- t1_slice = Im1
- t2_slice = Im2
- hist_2d, x_edges, y_edges = np.histogram2d(t1_slice.ravel(),t2_slice.ravel(),bins=20)
- hist_2d_log = np.zeros(hist_2d.shape)
- non_zeros = hist_2d != 0
- hist_2d_log[non_zeros] = np.log(hist_2d[non_zeros])
-
- pxy = hist_2d / float(np.sum(hist_2d))
- px = np.sum(pxy, axis=1) # marginal for x over y
- py = np.sum(pxy, axis=0) # marginal for y over x
- px_py = px[:, None] * py[None, :] # Broadcast to multiply marginals
- # Now we can do the calculation using the pxy, px_py 2D arrays
- nzs = pxy > 0 # Only non-zero pxy values contribute to the sum
- MI = np.sum(pxy[nzs] * np.log(pxy[nzs] / px_py[nzs]))
-
- return MI
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