Lattice Builder Manual Software Package for Constructing Rank-1 Lattices

- Main Page
- Related Pages
- Modules
- Namespaces
- Classes
- Files
- Examples

All Classes Namespaces Files Functions Variables Typedefs Enumerations Friends Modules Pages
tutorial/WeightedFigureOfMeritSignals.cc

This example shows how to use signals in order to interrupt the computation of a weighted figure of merit when its value has become too large.

// Copyright (c) 2012 David Munger, Pierre L'Ecuyer, Université de Montréal.
//
// This file is part of Lattice Builder.
//
// Lattice Builder 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 3 of the License, or
// (at your option) any later version.
//
// Lattice Builder 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 Lattice Builder. If not, see <http://www.gnu.org/licenses/>.
#include "latbuilder/WeightedFigureOfMerit.h"
#include "latcommon/ProductWeights.h"
#include "latcommon/CoordinateSets.h"
#include "latbuilder/ProjDepMerit/Spectral.h"
#include "latcommon/NormaBestLat.h"
#include "latbuilder/Accumulator.h"
#include "latbuilder/Storage.h"
#include "latbuilder/Functor/binary.h"
#include "latbuilder/LatSeq/Korobov.h"
#include "latbuilder/GenSeq/CoprimeIntegers.h"
#include "latbuilder/TextStream.h"
#include <iostream>
#include <limits>
using namespace LatBuilder;
using TextStream::operator<<;
template <typename T, typename... ARGS>
std::unique_ptr<T> unique(ARGS&&... args)
{ return std::unique_ptr<T>(new T(std::forward<ARGS>(args)...)); }
class Observer {
public:
typedef LatBuilder::LatDef<LatType::ORDINARY> LatDef;
Observer() { reset(); }
// initializes the best observed merit value to infinity
void reset() { m_bestMerit = std::numeric_limits<Real>::infinity(); }
// returns the best observed lattice
const LatDef& bestLat() { return m_bestLat; }
// returns the best observed merit value
const Real bestMerit() { return m_bestMerit; }
// notifies the observer that the merit value of a new candidate lattice has
// been observed; updates the best observed candidate lattice if necessary
void observe(const LatDef& lat, Real merit)
{
std::cout << lat << "\t:\t" << merit;
if (merit < m_bestMerit) {
std::cout << " <-- best";
m_bestMerit = merit;
m_bestLat = lat;
}
std::cout << std::endl;
}
bool onProgress(Real merit) const
{ return merit < m_bestMerit; }
void onAbort(const LatDef& lat) const
{ std::cout << "rejected " << lat << std::endl; }
private:
LatDef m_bestLat;
Real m_bestMerit;
};
template <LatType L, Compress C>
void test(const Storage<L, C>& storage, Dimension dimension)
{
auto weights = unique<LatCommon::ProductWeights>();
weights->setDefaultWeight(0.7);
typedef ProjDepMerit::Spectral<LatCommon::NormaBestLat> ProjDep;
WeightedFigureOfMerit<ProjDep, Functor::Max> figure(2, std::move(weights));
std::cout << "figure of merit: " << figure << std::endl;
// sequence of lattice definitions
typedef GenSeq::CoprimeIntegers<decltype(figure)::suggestedCompression()> Coprime;
auto latSeq = LatSeq::korobov(
storage.sizeParam(),
Coprime(storage.sizeParam().numPoints()),
dimension
);
LatCommon::CoordinateSets::FromRanges allProjections(
1, latSeq.latDimension(), // range for dimension
0, latSeq.latDimension() - 1 // range for coordinate index
);
std::cout << "projections: " << allProjections << std::endl;
auto initialMerit = storage.createMeritValue(0.0);
auto eval = figure.evaluator(storage);
Observer obs;
eval.onProgress().connect(boost::bind(&Observer::onProgress, &obs, _1));
eval.onAbort().connect(boost::bind(&Observer::onAbort, &obs, _1));
for (const auto& lat : latSeq) {
// compute merit value of lattice for all projections
auto merit = eval(lat, allProjections, initialMerit);
// notify the observer
obs.observe(lat, merit);
}
std::cout << "BEST LATTICE: " << obs.bestLat() << " with merit value " << obs.bestMerit() << std::endl;
}
int main()
{
Dimension dim = 3;
test(Storage<LatType::ORDINARY, Compress::SYMMETRIC>(19), dim);
return 0;
}