row_constraint.cc

#include<scil/global.h>
#include<scil/row_constraint.h>
#include<scil/var_obj.h>
#include<scil/row.h>
#include<cstdlib>
#include<vector>
#include<algorithm>

using namespace SCIL;

row_constraint::row_constraint(row& r, cons_sense s)
{
  NZ.reserve(r.size());

  std::list<row_entry>::const_iterator it;
  for( it = r.begin(); it!=r.end(); it++ ){
    NZ.push_back( pair(it->Var, it->coeff) );
  }

  set_sense(s);
  set_rhs(rhs());
}


double row_constraint::rhs()
{
  if( NZ[0].v==nil ) return -NZ[0].c;
  return 0;
}


double row_constraint::coeff(var_obj* v)
{
  vector<pair>::iterator lb;

  // search first pair in NZ with variable greater or equal to v
  lb = std::lower_bound< vector<pair>::iterator >(NZ.begin(), NZ.end(), pair(var(v),0), compareByVar);

  // if there's such a pair and the variables agree with v, return associated coeff
  if((lb != NZ.end()) && (lb->v == var(v)))
    return lb->c;

  // else all pair have variable strict less than v or there is no pair with variable v
  // non-existence <--> pair with coefficient zero
  return 0;
}

void row_constraint::non_zero_entries(row& r)
{
  for( int i=0; i<(int)NZ.size(); i++ ){
    if( NZ[i].v!=nil ) r+= row_entry( NZ[i].v, NZ[i].c );
  }
}

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