Source Code for Module maths_fns.potential

 1  ############################################################################### 
 2  #                                                                             # 
 3  # Copyright (C) 2009 Edward d'Auvergne                                        # 
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 5  # This file is part of the program relax.                                     # 
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21  ############################################################################### 
22   
23  # Module docstring. 
24  """Functions for calculating various optimisation potentials.""" 
25   
26   
27 -def quad_pot(values, pot, lower, upper): 
28      """Calculate the flat-bottom quadratic energy potential. 
29   
30      The formula used is:: 
31   
32                              / (x - x+)^2    if x > x+, 
33                              |                          
34          V_pQuad(x;x+,x-) = <  (x - x-)^2    if x < x-, 
35                              |                          
36                              \ 0             otherwise. 
37   
38      Where x+ and x- are the absolute bounds. 
39   
40   
41      @param values:  An array of values of x. 
42      @type values:   numpy float array 
43      @param pot:     The array to place the potential values (V_pQuad) into.  This should have the 
44                      same dimensions as the values array. 
45      @type pot:      numpy float array 
46      @param lower:   The array of lower bounds.  This should have the same dimensions as the values 
47                      array. 
48      @type lower:    numpy float array 
49      @param upper:   The array of upper bounds.  This should have the same dimensions as the values 
50                      array. 
51      @type upper:    numpy float array 
52      """ 
53   
54      # Loop over the x values. 
55      for i in xrange(len(values)): 
56          # First condition. 
57          if values[i] > upper[i]: 
58              pot[i] = (values[i] - upper[i])**2 
59   
60          # Second contition. 
61          elif values[i] < lower[i]: 
62              pot[i] = (values[i] - lower[i])**2 
63   
64          # Otherwise clear the array element. 
65          else: 
66              pot[i] = 0.0 
67