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Short helpfile for action UWALLS
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The input trajectory can be in any of the following formats: 

                 CATOMS - all the angles between the bonds that radiate out from 
                          these central atom are computed. For more information on how to 
                          specify lists of atoms see \ref Group 
                  GROUP - a list of angls between pairs of bonds connecting one of 
                          the atoms specified using the CATOM command and two of the 
                          atoms specified here are computed. For more information on how to 
                          specify lists of atoms see \ref Group 

The following arguments are compulsory: 

                   DATA - the values you want to restrain 
                     AT - the radius of the sphere 
                  KAPPA - the force constant for the wall. The k_i in the expression 
                          for a wall. 
                 OFFSET - ( default=0.0 ) the offset for the start of the wall. The 
                          o_i in the expression for a wall. 
                    EXP - ( default=2.0 ) the powers for the walls. The e_i in the 
                          expression for a wall. 
                    EPS - ( default=1.0 ) the values for s_i in the expression for a 
                          wall 
                 SWITCH - the switching function specifies that only those bonds that 
                          have a length that is less than a certain threshold are 
                          considered 

