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layerview.py 6.07 KB
71d5696d   David Mayerich   First commit afte...
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  # create a function that displays the output when run this way:
  #	python layerview.py ouput.dat
  
  import sys
  import os
  from time import time
  import subprocess
  import struct
  import numpy as np
  import matplotlib
  import math
  import matplotlib.pyplot as plt
  
  from mpl_toolkits.axes_grid1 import ImageGrid
  
  def intensity(E):
      Econj = np.conj(E)
      I = np.sum(E*Econj, axis=-1)
      return np.real(I)
  
  #evaluate a solved homogeneous substrate
  # Returns a complex NxMx3 array representing the cross section of the field at Y=0
  def evaluate(Depths, k, d, n0, sz, Pt, Pr, X, Y, Z):
      Depths = np.array(Depths)
      sz = np.array(sz)
      Pt = np.array(Pt)
      Pr = np.array(Pr)
      s = np.array(d) * n0
      #allocate space for layer indices
      LI = np.zeros(Z.shape, dtype=np.int)
              
      #find the layer index for each sample point
      L = len(Depths)
      LI[Z < Depths[0]] = 0
      for l in range(L-1):
          idx = np.logical_and(Z > Depths[l], Z <= Depths[l+1])
          LI[idx] = l
          LI[Z > Depths[-1]] = L - 1
      
      #calculate the appropriate phase shift for the wave transmitted through the layer
      Ph_t = np.exp(1j * k * sz[LI] * (Z - Depths[LI]))
      
      #calculate the appropriate phase shift for the wave reflected off of the layer boundary
      LIp = LI + 1
      LIp[LIp >= L] = 0
      Ph_r = np.exp(-1j * k * sz[LI] * (Z - Depths[LIp]))
      Ph_r[LI >= L-1] = 0
      
      #calculate the phase shift based on the X and Y positions
      Ph_xy = np.exp(1j * k * (s[0] * X + s[1] * Y))
      
      #apply the phase shifts
      Et = Pt[:, LI] * Ph_t[:, :]
      Er = Pr[:, LI] * Ph_r[:, :]
      
      #add everything together coherently
      E = (Et + Er) * Ph_xy[:, :]
      
      #return the electric field
      return np.moveaxis(E, 0, -1)
          
  class planewave:
      def __int__(self):
          self.LAYERS = 0                          #Number of layers.                          int
          self.depths = []                         #z positions of layers. [1, 5, ..., 10]     double
          self.k0 = 0.0                              #wavenumber at free space.                  double
          self.d = []                              #direction of propogation. [0.5, 0]         double
          self.n0 = 0.0+0.0j                           #the refractive index of the first layer.   complex<double>
          self.sz = []                             #z-component of propagation for each layer. complex<double>
          self.Pt = [[] for i in range(3)]         #transmission                               complex<double>
          self.Pr = [[],[],[]]                     #refraction                                 complex<double>
          
  # display a binary file produced using the coupled wave C code
  def layer(strc):    
      f = open(strc, "rb")
  
      # create an empty plane wave structure
      L = planewave()
      L.depths = []
      L.d = []
      L.sz = []
      L.Pt = [[],[],[]]
      L.Pr = [[],[],[]]
  
      # open the input file for reading
      file_bytes = os.path.getsize(strc)
  
      # calculate the number of layers in the sample
      L.LAYERS = int((file_bytes/8-5)/15)
  
      # load the raw layer data into the plane wave structure
      data_raw = struct.unpack('d' * (15*L.LAYERS+5), f.read((15*L.LAYERS+5)* 8))
      data = np.asarray(data_raw)    
      L.k0 = data[0]
      L.d.append(data[1])
      L.d.append(data[2])
      L.n0 = complex(data[3], data[4])
  
      # load each layer's plane waves from the binary file
      for i in range(L.LAYERS):
          L.depths.append(data[5+15*i])
          L.sz.append(complex(data[6+15*i], data[7+15*i]))
          L.Pt[0].append(complex(data[8+15*i], data[9+15*i]))
          L.Pt[1].append(complex(data[15*i+10], data[15*i+11]))
          L.Pt[2].append(complex(data[15*i+12], data[15*i+13]))
          L.Pr[0].append(complex(data[15*i+14], data[15*i+15]))
          L.Pr[1].append(complex(data[15*i+16], data[15*i+17]))
          L.Pr[2].append(complex(data[15*i+18], data[15*i+19]))
  
      N = 512															# simulation resolution NxM
      M = 1024
      #DAVID: Don't hard-code the dimensions - you'll have to calculate them based on the sample information in the file
      D = [-110, 110, 0, 60]											# dimensions of the simulation
      x = np.linspace(D[2], D[3], N)									# set the sample points for the simulation
      z = np.linspace(D[0], D[1], M)
      [X, Z] = np.meshgrid(x, z)										# create a mesh grid to evaluate layers
      Y = np.zeros(X.shape)
  
      # evaluate the field across all layers
      E = evaluate(L.depths, L.k0, L.d, L.n0, L.sz, L.Pt, L.Pr, X, Y, Z)
      Er = np.real(E)
      I = intensity(E)
  
      plt.set_cmap("afmhot")											# set the color map
      plt.subplot(1, 4, 1)
      plt.imshow(Er[:, :, 0], extent=(D[3], D[2], D[1], D[0]))
      #plt.colorbar()
      plt.title("Ex")
  
      plt.subplot(1, 4, 2)
      plt.imshow(Er[:, :, 1], extent=(D[3], D[2], D[1], D[0]))
      #plt.colorbar()
      plt.title("Ey")
  
      plt.subplot(1, 4, 3)
      plt.imshow(Er[:, :, 2], extent=(D[3], D[2], D[1], D[0]))
      #plt.colorbar()
      plt.title("Ez")
  
      plt.subplot(1, 4, 4)
      plt.imshow(I, extent=(D[3], D[2], D[1], D[0]))
      plt.colorbar()
      plt.title("I")
      
      #fig = plt.figure(1, (5, 10))
      #plt.set_cmap("afmhot")
      #matplotlib.rcParams.update({'font.size': 10})
      #grid = ImageGrid(fig, rect = 211, nrows_ncols = (1, 3), axes_pad = 0.2, label_mode = "1", cbar_mode = "single", cbar_size = "18%")
      #Title = ["Ex", "Ey", "Ez"]
      #for i in range(3):
          # grid[i].axis('off')
      #    im = grid[i].imshow(Er[..., i], extent=(D[3], D[2], D[1], D[0]), interpolation="nearest")
      #    grid[i].set_title(Title[i])
      #grid.cbar_axes[0].colorbar(im)
      #plt.title("E")
      #plt.subplot(212)
      #plt.imshow(I, extent=(D[3], D[2], D[1], D[0]))
      #plt.title("I")
      #plt.colorbar()
      plt.show()
  
  # function displays usage text to the console
  def usage():
  	print("Usage:")
  	print("     layerview input.dat")
  
  if __name__ == '__main__':
      start = time()
      if len(sys.argv) < 2:				# if there are no command line arguments
      	usage()							# display the usage text
      	exit()							# exit
      else:
      	layer(sys.argv[1])				# otherwise display the given data file
  
      end = time()
      print("The elapsed time is " + str(end - start) + " s. ")