hitfit::Pair_Table Class Reference

A lookup table to speed up constraint evaluation using Fourvec_Constrainer. More...

#include <Pair_Table.h>

Public Member Functions
const Objpair &	get_pair (std::vector< Objpair >::size_type pairno) const
	Get one of the pairs from the table, index starts from 0. More...
int	npairs () const
	Return the number of pairs in the table. More...
	Pair_Table (const std::vector< Constraint > &cv, const Fourvec_Event &ev)
	Constructor, give it the event and the list of constraints. More...

Private Attributes
std::vector< Objpair >	_pairs

Detailed Description

A lookup table to speed up constraint evaluation using Fourvec_Constrainer.

We have a set of constraints, which reference labels, like

We also have a Fourvec_Event, which has a set of objects, each of which has a label. A label may correspond to multiple objects.

We'll be evaluating the mass constraints by considering each pair of objects and and finding its contribution to each constraint. We get pairs because the constraints are quadratic in the objects.

We build a Pair_Table by calling the constructor, giving it the event, and the set of constraints. We can then get back from it a list of Objpair's each representing a pair of objects that are used in some constraint. The Objpair will be able to tell us in which constraints the pair is used and on which side of the equation.

Definition at line 99 of file Pair_Table.h.

Constructor & Destructor Documentation

hitfit::Pair_Table::Pair_Table	(	const std::vector< Constraint > &	cv,
		const Fourvec_Event &	ev
	)

Constructor, give it the event and the list of constraints.

Parameters

cv	The list of constraints for the problem.
ev	The event.

Definition at line 48 of file Pair_Table.cc.

References _pairs, hitfit::Objpair::has_constraint(), mps_fire::i, gen::k, hitfit::FE_Obj::label, hitfit::Fourvec_Event::nobjs_all(), hitfit::Fourvec_Event::obj(), AlCaHLTBitMon_ParallelJobs::p, and heppy_batch::val.

{
  // The number of objects in the event, including any neutrino.
  int nobjs = ev.nobjs_all();

  // Number of constraints.
  int nc = cv.size();

  // Loop over pairs of objects.
  for (int i=0; i < nobjs-1; i++)
    for (int j=i+1; j < nobjs; j++) {
      // Make an Objpair instance out of it.
      Objpair p (i, j, nc);

      // Loop over constraints.
      bool wanted = false;
      for (int k=0; k < nc; k++) {
        int val = cv[k].has_labels (ev.obj (i).label, ev.obj (j).label);
        if (val) {
          // This pair is used by this constraint.  Record it.
          p.has_constraint (k, val);
          wanted = true;
        }
      }

      // Was this pair used by any constraint?
      if (wanted)
        _pairs.push_back (p);
    }
}

Member Function Documentation

const Objpair & hitfit::Pair_Table::get_pair

(

std::vector< Objpair >::size_type

pairno

)

const

Get one of the pairs from the table, index starts from 0.

Parameters

pairno

The index of the pair, index starts from 0.

Definition at line 100 of file Pair_Table.cc.

References _pairs.

Referenced by hitfit::operator<<().

{
  assert (pairno < _pairs.size());
  return _pairs[pairno];
}

int hitfit::Pair_Table::npairs

(

)

const

Return the number of pairs in the table.

Definition at line 88 of file Pair_Table.cc.

References _pairs.

Referenced by hitfit::operator<<().

{
  return _pairs.size();
}

Member Data Documentation

std::vector<Objpair> hitfit::Pair_Table::_pairs

private

The list of pairs.

Definition at line 137 of file Pair_Table.h.

Referenced by get_pair(), npairs(), and Pair_Table().