GaussianGenerator.h

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#pragma once
 
#include <random>
 
#include "autopas/utils/ArrayUtils.h"
#include "autopas/utils/ParticleTypeTrait.h"
#include "autopas/utils/inBox.h"
 
namespace autopasTools::generators::GaussianGenerator {
constexpr size_t _maxAttempts = 100;
 
template <class Container>
void fillWithParticles(Container &container, const std::array<double, 3> &boxMin, const std::array<double, 3> &boxMax,
                       size_t numParticles,
                       const typename autopas::utils::ParticleTypeTrait<Container>::value &defaultParticle =
                           typename autopas::utils::ParticleTypeTrait<Container>::value(),
                       const std::array<double, 3> &distributionMean = {5., 5., 5.},
                       const std::array<double, 3> &distributionStdDev = {2., 2., 2.}) {
  std::default_random_engine generator(42);
  std::array<std::normal_distribution<double>, 3> distributions = {
      std::normal_distribution<double>{distributionMean[0], distributionStdDev[0]},
      std::normal_distribution<double>{distributionMean[1], distributionStdDev[1]},
      std::normal_distribution<double>{distributionMean[2], distributionStdDev[2]}};
 
  for (unsigned long i = defaultParticle.getID(); i < defaultParticle.getID() + numParticles; ++i) {
    std::array<double, 3> position = {distributions[0](generator), distributions[1](generator),
                                      distributions[2](generator)};
    // verifies that position is valid
    for (size_t attempts = 1; attempts <= _maxAttempts and (not autopas::utils::inBox(position, boxMin, boxMax));
         ++attempts) {
      if (attempts == _maxAttempts) {
        std::ostringstream errormessage;
        errormessage << "GaussianGenerator::fillWithParticles(): Could not find a valid position for particle " << i
                     << "after" << _maxAttempts << "attempts. Check if your parameters make sense:" << std::endl
                     << "BoxMin       = " << autopas::utils::ArrayUtils::to_string(boxMin) << std::endl
                     << "BoxMax       = " << autopas::utils::ArrayUtils::to_string(boxMax) << std::endl
                     << "Gauss mean   = " << autopas::utils::ArrayUtils::to_string(distributionMean) << std::endl
                     << "Gauss stdDev = " << autopas::utils::ArrayUtils::to_string(distributionStdDev) << std::endl;
        throw std::runtime_error(errormessage.str());
      }
      position = {distributions[0](generator), distributions[1](generator), distributions[2](generator)};
    };
    auto p = defaultParticle;
    p.setR(position);
    p.setID(i);
    container.addParticle(p);
  }
}
}  // namespace autopasTools::generators::GaussianGenerator