add another grey example

multi_grey.py

@@ -0,0 +1,30 @@
+# -*- coding: utf-8 -*-
+"""
+Created on Tue Mar 24 10:51:10 2020
+
+@author: Tom
+"""
+
+import pytrax as pt
+import numpy as np
+import matplotlib.pyplot as plt
+plt.close('all')
+
+if __name__ == '__main__':
+ im = np.ones([1000, 1000])
+ # Number of time steps and walkers
+ num_t = 10000
+ num_w = 800
+ stride = 1
+ grey_vals = np.logspace(-1, 1, 10)
+ tau = []
+ for grey_val in grey_vals:
+ grey = im.copy()
+ grey = grey.astype(float)
+ grey[grey == 1.0] = grey_val
+ rw = pt.RandomWalk(grey, seed=False)
+ rw.run(num_t, num_w, same_start=False, stride=stride, num_proc=1)
+ rw.plot_msd()
+ tau.append(rw.data['axis_0_tau'])
+ plt.figure()
+ plt.loglog(grey_vals, tau)