Source Code for Module pipe_control.fix

 1  ############################################################################### 
 2  #                                                                             # 
 3  # Copyright (C) 2003-2004,2007-2008 Edward d'Auvergne                         # 
 4  #                                                                             # 
 5  # This file is part of the program relax (http://www.nmr-relax.com).          # 
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20  ############################################################################### 
21   
22  # Module docstring. 
23  """Module for holding certain model components fixed during optimisation.""" 
24   
25  # relax module imports. 
26  from lib.errors import RelaxError, RelaxNoSequenceError, RelaxNoTensorError 
27  from pipe_control.mol_res_spin import exists_mol_res_spin_data, spin_loop 
28  from pipe_control.pipes import check_pipe 
29   
30   
31 -def fix(element, fixed): 
32      """Fix or allow certain model components values to vary during optimisation. 
33   
34      @param element:     The model component to fix or unfix.  If set to 'diff', then the diffusion 
35                          parameters can be toggled.  If set to 'all_spins', then all spins can be 
36                          toggled.  If set to 'all', then all model components are toggled. 
37      @type element:      str. 
38      """ 
39   
40      # Test if the current data pipe exists. 
41      check_pipe() 
42   
43      # Diffusion tensor. 
44      if element == 'diff' or element == 'all': 
45          # Test if the diffusion tensor data is loaded. 
46          if not hasattr(cdp, 'diff_tensor'): 
47              raise RelaxNoTensorError('diffusion') 
48   
49          # Set the fixed flag. 
50          cdp.diff_tensor.set_fixed(fixed) 
51   
52      # All spins. 
53      if element == 'all_spins' or element == 'all': 
54          # Test if sequence data exists. 
55          if not exists_mol_res_spin_data(): 
56              raise RelaxNoSequenceError 
57   
58          # Loop over the sequence and set the fixed flag. 
59          for spin in spin_loop(): 
60              # Skip deselected spins. 
61              if not spin.select: 
62                  continue 
63   
64              # Set the flag. 
65              spin.fixed = fixed 
66   
67   
68      # Unknown. 
69      if element not in ['diff', 'all_spins', 'all']: 
70          raise RelaxError("The 'element' argument " + repr(element) + " is unknown.") 
71