Source Code for Module theia.optics.thinlens

  1  '''Defines the ThinLens class for theia.''' 
  2   
  3  # Provides: 
  4  #   class ThinLens 
  5  #       __init__ 
  6  #       lines 
  7   
  8  import numpy as np 
  9  from ..helpers import settings 
 10  from ..helpers.units import mm, cm, deg, pi 
 11  from ..helpers.geometry import rectToSph 
 12  from .optic import Optic 
 13   
 14 -class ThinLens(Optic): 
 15      ''' 
 16   
 17      ThinLens class. 
 18   
 19      This class represents thin lenses, which are specified only by their focal 
 20      lengths, diameter, position and orientation. Only the initializer and the 
 21      printing distinguishes thin lenses (in implementation) from other lenses. 
 22   
 23      Actions: 
 24          * T on HR: 0 
 25          * R on HR: + 1 
 26          * T on AR: 0 
 27          * R on AR: + 1 
 28   
 29      *=== Additional attributes with respect to the Optic class ===* 
 30   
 31      Focal: focal length of the lens  as given in initializer. [float] 
 32   
 33      *=== Name ===* 
 34   
 35      ThinLens 
 36   
 37      **Note**: the curvature of any surface is positive for a concave surface 
 38      (coating inside the sphere). 
 39      Thus kurv*HRNorm/|kurv| always points to the center 
 40      of the sphere of the surface, as is the convention for the lineSurfInter of 
 41      geometry module. Same for AR. 
 42   
 43      *******     HRK > 0 and ARK > 0     *******           HRK > 0 and ARK < 0 
 44       *****                               ********         and |ARK| > |HRK| 
 45       H***A                               H*********A 
 46       *****                               ******** 
 47      *******                             ******* 
 48   
 49   
 50      ''' 
 51   
 52      Name = "ThinLens" 
 53   
 54 -    def __init__(self, Focal = 10.e-2, KeepI = False, Theta = pi/2., Phi = 0., 
 55                  Diameter = 5.e-2, R = .1, T = .9, 
 56                  X = 0., Y = 0., Z = 0., Ref = None): 
 57          '''ThinLens initializer. 
 58   
 59          Parameters are the attributes. 
 60   
 61          Returns a ThinLens. 
 62   
 63          ''' 
 64          # actions 
 65          TonHR = 0 
 66          RonHR = 1 
 67          TonAR = 0 
 68          RonAR = 1 
 69   
 70          # initialize focal and check data 
 71          self.Focal = float(Focal) 
 72          Theta = float(Theta) 
 73          Phi = float(Phi) 
 74          Diameter = float(Diameter) 
 75          R = float(R) 
 76          T = float(T) 
 77          Wedge = 0. 
 78          Alpha = 0. 
 79   
 80          #prepare for mother initializer 
 81          HRNorm = np.array([np.sin(Theta)*np.cos(Phi), 
 82                          np.sin(Theta) * np.sin(Phi), 
 83                          np.cos(Theta)], dtype = np.float64) 
 84          Center = np.array([X, Y, Z], dtype = np.float64) 
 85          N = 1.4548 
 86   
 87          # thin lens approximation of lensmaker's equation 
 88          HRK = - 0.5/(self.Focal*(N - 1.)) 
 89          ARK = HRK 
 90          ARNorm = - HRNorm 
 91   
 92          # calculate  ARCenter, ARNorm  and HRCenter with focal 
 93          if self.Focal >= 0.: 
 94              Thickness = settings.zero 
 95          else: 
 96              try:    #arcsin might fail, if it does then the semi angle is pi/2 
 97                  theta = np.arcsin(Diameter * HRK/2.)   # half angle 
 98              except FloatingPointError: 
 99                  theta = pi/2. 
100              Thickness = 2.*settings.zero + 2.*(1.-np.cos(theta))/HRK 
101          HRCenter = Center + Thickness*HRNorm/2. 
102          ARCenter = Center - Thickness*HRNorm/2. 
103   
104          # initialize with lens mother initializer 
105          super(ThinLens, self).__init__(ARCenter = ARCenter, ARNorm = ARNorm, 
106                  N = N, 
107                  HRK = HRK, ARK = ARK, 
108                  ARr = R, ARt = T, HRr = R, HRt = T, KeepI = KeepI, 
109                  HRCenter = HRCenter, HRNorm = HRNorm, Thickness = Thickness, 
110                  Diameter = Diameter, Wedge = Wedge, Alpha = Alpha, 
111                  TonHR = TonHR, RonHR = RonHR, TonAR = TonAR, RonAR = RonAR, 
112                  Ref = Ref) 
113   
114          #warns on geometry 
115          if settings.warning: 
116              self.geoCheck("thinlens") 
117   
118 -    def lines(self): 
119          '''Returns the list of lines necessary to print the object. 
120          ''' 
121          sph = rectToSph(self.HRNorm) 
122          return ["ThinLens: %s {" % str(self.Ref), 
123          "Diameter: %scm" % str(self.Dia/cm), 
124          "Focal: %smm" % str(self.Focal/mm), 
125          "Center: %s" % str(self.HRCenter), 
126          "Norm: (%s, %s)deg" % (str(sph[0]/deg), str(sph[1]/deg)), 
127          "HRKurv, ARKurv: %s, %s" % (str(self.HRK), str(self.ARK)), 
128          "R, T: %s, %s" % (str(self.HRr),str(self.HRt)), 
129          "}"] 
130