old_contents: #! /usr/bin/env python
  #
  # This routine can diff images from its neighbors.  For a series i=1,N
  # this can loop over i=2,N to produce N-1 difference images
  #
  #   B_i = A_i - A_i-1 
  #
  
  from __future__ import print_function
  
  import glob
  import sys
  import shutil
  import os
  from astropy.io import fits
  import numpy as np
  
  
  if len(sys.argv) == 3:
      f1 = sys.argv[1]
      f2 = sys.argv[2]
      print("Using %s %s" % (f1,f2))
  
  hdu1 = fits.open(f1)
  hdu2 = fits.open(f2)
  
  h2 = hdu2[0].header
  
  d1 = hdu1[0].data.astype(np.float32)
  d2 = hdu2[0].data.astype(np.float32)
  
  print(f1,d1.min(),d1.max())
  print(f2,d2.min(),d2.max())
  
  diff = d2 - d1
  
  max1 = d1.max()
  std1 = diff.std()
  fidelity = max1 / std1
  
  
  
  print("MEAN/STD/FID:",diff.mean(), std1, fidelity)
  fits.writeto('diff.fits',diff,h2,overwrite=True)
  #
  #fid  = np.abs(d2) / np.max(np.abs(diff),std1/1.4)
  #fits.writeto('fidelity.fits',fid,h2,overwrite=True)
  
  try:
      import matplotlib.pyplot as plt
      plt.figure(1)
      plt.hist(diff.ravel())
      plt.show()
  except:
      print("Failing to plot")
  
  
new_contents: #! /usr/bin/env python
  #
  # This routine can diff images from its neighbors.  For a series i=1,N
  # this can loop over i=2,N to produce N-1 difference images
  #
  #   B_i = A_i - A_i-1 
  #
  
  from __future__ import print_function
  
  import glob
  import sys
  import shutil
  import os
  from astropy.io import fits
  import numpy as np
  
  
  if len(sys.argv) == 3:
      f1 = sys.argv[1]
      f2 = sys.argv[2]
      print("Using %s %s" % (f1,f2))
  
  hdu1 = fits.open(f1)
  hdu2 = fits.open(f2)
  
  h2 = hdu2[0].header
  
  d1 = hdu1[0].data.astype(np.float32)
  d2 = hdu2[0].data.astype(np.float32)
  
  print(f1,d1.min(),d1.max())
  print(f2,d2.min(),d2.max())
  
  diff = d2 - d1
  
  max1 = d1.max()
  std1 = diff.std()
  fidelity = max1 / std1
  
  
  
  print("MEAN/STD/FID:",diff.mean(), std1, fidelity)
  
  if False:
      fits.writeto('diff.fits',diff,h2,overwrite=True)
  #
  #fid  = np.abs(d2) / np.max(np.abs(diff),std1/1.4)
  #fits.writeto('fidelity.fits',fid,h2,overwrite=True)
  
  try:
      import matplotlib.pyplot as plt
      plt.figure(1)
      plt.hist(diff.ravel())
      plt.show()
  except:
      print("Failing to plot")
  
  
subject: disable diff file writing for demo mode (RP3 got too hot)