paradiseo/eo/src/utils/eoHowMany.h
2001-12-03 06:59:17 +00:00

129 lines
3.6 KiB
C++

// -*- mode: c++; c-indent-level: 4; c++-member-init-indent: 8; comment-column: 35; -*-
//-----------------------------------------------------------------------------
// eoHowMany_h.h
// Base class for choosing a number of guys to apply something from a popsize
// (c) Marc Schoenauer, 2000
/*
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Contact: todos@geneura.ugr.es, http://geneura.ugr.es
*/
//-----------------------------------------------------------------------------
#ifndef eoHowMany_h
#define eoHowMany_h
/**
* to be used in selection / replacement procedures to indicate whether
* the argument (rate, a double) shoudl be treated as a rate (number=rate*popSize)
* or as an absolute integer (number=rate regardless of popsize).
* the default value shoudl ALWAYS be true (eo_as_a_rate).
*
* this construct is mandatory because in some cases you might not know the
* population size that will enter the replacement. For instance, you
* cannot simply have a pre-computed (double) rate of 1/popSize
* if you want 1 guy
*
* Example use: in <a href="class_eogeneralbreeder.html">eoGeneralBreeder.h</a>
* Example reading from parser: in
* <a href="make_algo_scalar_h-source.html">do/make_algo_scalar.h line 141</a>
*/
class eoHowMany : public eoPersistent
{
public:
/** Original Ctor from direct rate + bool */
eoHowMany(double _rate = 0.0, bool _interpret_as_rate = true):
rate(0), combien(0)
{
if (_interpret_as_rate)
{
rate = _rate;
}
else
{
if (_rate<0)
throw std::logic_error("Negative number in eoHowMany!");
combien = (unsigned int)_rate;
if (combien != _rate)
cout << "Warning: Number was rounded in eoHowMany";
}
}
/// Virtual dtor. They are needed in virtual class hierarchies.
virtual ~eoHowMany() {}
unsigned int operator()(unsigned int _size)
{
if (combien == 0)
{
return (unsigned int) (rate * _size);
}
return combien;
}
virtual void printOn(ostream& _os) const
{
if (combien == 0)
_os << 100*rate << "% " << std::ends;
else
_os << combien << " " << std::ends;
return;
}
virtual void readFrom(istream& _is)
{
string value;
_is >> value;
readFrom(value);
return;
}
void readFrom(std::string _value)
{
// check for %
bool interpret_as_rate = false; // == no %
size_t pos = _value.find('%');
if (pos < _value.size()) // found a %
{
interpret_as_rate = true;
_value.resize(pos); // get rid of %
}
std::istrstream is(_value.c_str());
is >> rate;
// now store
if (interpret_as_rate)
{
combien = 0;
rate /= 100.0;
}
else
combien = unsigned(rate); // and rate will not be used
// minimal check
if ( (combien <= 0) && (rate <= 0.0) )
throw runtime_error("Invalid parameters read in eoHowMany::readFrom");
}
private :
double rate;
unsigned combien;
};
#endif