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// -*- C++ -*-
//
// MaxCmp.h is a part of ThePEG - Toolkit for HEP Event Generation
// Copyright (C) 1999-2011 Leif Lonnblad
//
// ThePEG is licenced under version 2 of the GPL, see COPYING for details.
// Please respect the MCnet academic guidelines, see GUIDELINES for details.
//
#ifndef THEPEG_MaxCmp_H
#define THEPEG_MaxCmp_H
//
// This is the declaration of the MaxCmp class.
//
#include <functional>
namespace ThePEG {
/**
* MaxCmp is a helper class to be used in a loop where one would like
* to keep track of the largest value so far of a certain
* expression. The class simply checks if the given value to the
* operator() is the largest so far (in which case true is returned,
* and the value is saved together with the optional index
* argument. The Cmp template argument is by default greater<T>, but
* can be set to any comparison class to change the meaning of
* maximum: MaxCmp<double, int, less<double> > will keep track of the
* smallest value.
*/
template <typename T = double, typename Indx = int, typename Cmp = std::greater<T> >
class MaxCmp {
public:
/**
* The default constructor.
*/
MaxCmp() : init(false), max(T()), indx(Indx()) {}
/**
* Constructor specifying an initial maximum value, \a t.
*/
MaxCmp(const T & t, Indx in = Indx()) : init(true), max(t), indx(in) {}
public:
/**
* If \a t is the largest value seen so far return true. Otherwise
* return false. \a i is an optional index for the value \a t.
*/
bool operator()(const T & t, Indx i = Indx())
{
if ( !init || cmp(t, max) ) {
max = t;
init = true;
indx = i;
return true;
}
return false;
}
/**
* Return the largest value so far.
*/
operator const T & () const { return value(); }
/**
* Return the largest value so far.
*/
const T & value() const { return max; }
/**
* Return the index of the largest object seen so far.
*/
Indx index() const {
return indx;
}
private:
/**
* True if a first value has been given;
*/
bool init;
/**
* The largest value seen so far.
*/
T max;
/**
* The index for the largest value seen so far.
*/
Indx indx;
/**
* The comparison object to be used.
*/
Cmp cmp;
};
/**
* Special calss for Minimum comparisons.
*/
template <typename T, typename Indx = int>
class MinCmp: public MaxCmp<T, Indx, less<T> > {
public:
/**
* Constructors are not inherited.
*/
MinCmp() {}
/**
* Constructors are not inherited.
*/
MinCmp(const T & t, Indx in = Indx()) : MaxCmp<T, Indx, less<T> >(t, in) {}
};
}
#endif /* THEPEG_MaxCmp_H */
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