Source Code for Module lib.structure.angles

 1  ############################################################################### 
 2  #                                                                             # 
 3  # Copyright (C) 2003-2010,2012-2014 Edward d'Auvergne                         # 
 4  # Copyright (C) 2008 Sebastien Morin                                          # 
 5  #                                                                             # 
 6  # This file is part of the program relax (http://www.nmr-relax.com).          # 
 7  #                                                                             # 
 8  # This program is free software: you can redistribute it and/or modify        # 
 9  # it under the terms of the GNU General Public License as published by        # 
10  # the Free Software Foundation, either version 3 of the License, or           # 
11  # (at your option) any later version.                                         # 
12  #                                                                             # 
13  # This program is distributed in the hope that it will be useful,             # 
14  # but WITHOUT ANY WARRANTY; without even the implied warranty of              # 
15  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               # 
16  # GNU General Public License for more details.                                # 
17  #                                                                             # 
18  # You should have received a copy of the GNU General Public License           # 
19  # along with this program.  If not, see <http://www.gnu.org/licenses/>.       # 
20  #                                                                             # 
21  ############################################################################### 
22   
23  # Python module imports. 
24  from math import pi 
25  from numpy import arccos, float64, zeros 
26   
27   
28 -def angles_regular(inc=None): 
29      """Determine the spherical angles for a regular sphere point distribution. 
30   
31      @keyword inc:   The number of increments in the distribution. 
32      @type inc:      int 
33      @return:        The phi angle array and the theta angle array. 
34      @rtype:         array of float, array of float 
35      """ 
36   
37      # Generate the increment values of u. 
38      u = zeros(inc, float64) 
39      val = 1.0 / float(inc) 
40      for i in range(inc): 
41          u[i] = float(i) * val 
42   
43      # Generate the increment values of v. 
44      v = zeros(int(inc/2.0+1.0), float64) 
45      val = 1.0 / float(inc/2.0) 
46      for i in range(int(inc/2.0+1.0)): 
47          v[i] = float(i) * val 
48   
49      # Generate the distribution of spherical angles theta. 
50      theta = 2.0 * pi * u 
51   
52      # Generate the distribution of spherical angles phi (from bottom to top). 
53      phi = zeros(len(v), float64) 
54      for i in range(len(v)): 
55          phi[len(v)-1-i] = pi * v[i] 
56   
57      # Return the angle arrays. 
58      return phi, theta 
59   
60   
61 -def angles_uniform(inc=None): 
62      """Determine the spherical angles for a uniform sphere point distribution. 
63   
64      @keyword inc:   The number of increments in the distribution. 
65      @type inc:      int 
66      @return:        The phi angle array and the theta angle array. 
67      @rtype:         array of float, array of float 
68      """ 
69   
70      # Generate the increment values of u. 
71      u = zeros(inc, float64) 
72      val = 1.0 / float(inc) 
73      for i in range(inc): 
74          u[i] = float(i) * val 
75   
76      # Generate the increment values of v. 
77      v = zeros(int(inc/2.0+2.0), float64) 
78      val = 1.0 / float(inc/2.0) 
79      for i in range(1, int(inc/2.0)+1): 
80          v[i] = float(i-1) * val + val/2.0 
81      v[-1] = 1.0 
82   
83      # Generate the distribution of spherical angles theta. 
84      theta = 2.0 * pi * u 
85   
86      # Generate the distribution of spherical angles phi. 
87      phi = arccos(2.0 * v - 1.0) 
88   
89      # Return the angle arrays. 
90      return phi, theta 
91