Source Code for Module lib.structure.angles

 1  ############################################################################### 
 2  #                                                                             # 
 3  # Copyright (C) 2003-2014 Edward d'Auvergne                                   # 
 4  #                                                                             # 
 5  # This file is part of the program relax (http://www.nmr-relax.com).          # 
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 7  # This program is free software: you can redistribute it and/or modify        # 
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15  # GNU General Public License for more details.                                # 
16  #                                                                             # 
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18  # along with this program.  If not, see <http://www.gnu.org/licenses/>.       # 
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20  ############################################################################### 
21   
22  # Python module imports. 
23  from math import pi 
24  from numpy import arccos, float64, zeros 
25   
26   
27 -def angles_regular(inc=None): 
28      """Determine the spherical angles for a regular sphere point distribution. 
29   
30      @keyword inc:   The number of increments in the distribution. 
31      @type inc:      int 
32      @return:        The phi angle array and the theta angle array. 
33      @rtype:         array of float, array of float 
34      """ 
35   
36      # Generate the increment values of u. 
37      u = zeros(inc, float64) 
38      val = 1.0 / float(inc) 
39      for i in range(inc): 
40          u[i] = float(i) * val 
41   
42      # Generate the increment values of v. 
43      v = zeros(inc/2+1, float64) 
44      val = 1.0 / float(inc/2) 
45      for i in range(int(inc/2+1)): 
46          v[i] = float(i) * val 
47   
48      # Generate the distribution of spherical angles theta. 
49      theta = 2.0 * pi * u 
50   
51      # Generate the distribution of spherical angles phi (from bottom to top). 
52      phi = zeros(len(v), float64) 
53      for i in range(len(v)): 
54          phi[len(v)-1-i] = pi * v[i] 
55   
56      # Return the angle arrays. 
57      return phi, theta 
58   
59   
60 -def angles_uniform(inc=None): 
61      """Determine the spherical angles for a uniform sphere point distribution. 
62   
63      @keyword inc:   The number of increments in the distribution. 
64      @type inc:      int 
65      @return:        The phi angle array and the theta angle array. 
66      @rtype:         array of float, array of float 
67      """ 
68   
69      # Generate the increment values of u. 
70      u = zeros(inc, float64) 
71      val = 1.0 / float(inc) 
72      for i in range(inc): 
73          u[i] = float(i) * val 
74   
75      # Generate the increment values of v. 
76      v = zeros(inc/2+2, float64) 
77      val = 1.0 / float(inc/2) 
78      for i in range(1, int(inc/2)+1): 
79          v[i] = float(i-1) * val + val/2.0 
80      v[-1] = 1.0 
81   
82      # Generate the distribution of spherical angles theta. 
83      theta = 2.0 * pi * u 
84   
85      # Generate the distribution of spherical angles phi. 
86      phi = arccos(2.0 * v - 1.0) 
87   
88      # Return the angle arrays. 
89      return phi, theta 
90