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constraint.cpp

//$Header: /home/ben/Mapper/c++/RCS/constraint.cpp,v 6.3 2002/06/14 22:28:47 ben Exp $
// Copyright Benedict Adamson 2002.
// This file is part of Mapper.

// Mapper is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.

// Mapper is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Mapper; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

#include <cassert>

#include "constraint.h"
#include "vector2.h"



constraint::constraint(
   const double u
   )
   :
   uncertainty_( u )
{
   {//postconditions:
      assert( this->uncertainty() == u );
      assert( this->points().empty() );
   };
}



constraint::~constraint(void)
{
}



void constraint::uncertainty(
   const double u
   )
{
   {//preconditions:
      assert( 0.0 <= u );
   };
   this->uncertainty_ = u;
   {//postconditions:
      assert( this->uncertainty() == u );
   };
}



double constraint::energy(
   const double tol
   ) const
{
   //tol is a dimensionless calculation tolerance.
   //A dimensionless measure of the potential energy of the constraint.
   //Larger values indicate the constraint is less well satisfied.
   //Conventionally, 0 is defined as the minimum possible energy,
   //And energy <= 1 indicates that the constraint is satisifed
   //to within the uncertainty of the constraint.
   {//precondition:
      assert( 0 < tol && tol < 1 );
      //assert( this->points()[i] ) for all i
   };
   const unsigned n = this->points().size();
   vector< vector2 > p(n), dedp(n);
   for( unsigned i = 0; i < n; i++ ){
      assert( this->points()[i] );
      p[i] = *(this->points()[i]);
   };
   double e;
   this->energy( tol, p, e, dedp );
   return e;
}
   

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