Sampler.h

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/* ----------------------------------------------------------------------------
 
 * GTSAM Copyright 2010, Georgia Tech Research Corporation,
 * Atlanta, Georgia 30332-0415
 * All Rights Reserved
 * Authors: Frank Dellaert, et al. (see THANKS for the full author list)
 
 * See LICENSE for the license information
 
 * -------------------------------------------------------------------------- */

 
#pragma once
 
#include <gtsam/base/Manifold.h>
#include <gtsam/linear/NoiseModel.h>
 
#include <random>
 
namespace gtsam {

class GTSAM_EXPORT Sampler {
 protected:
  noiseModel::Diagonal::shared_ptr model_;

  mutable std::mt19937_64 generator_;

  mutable std::mt19937_64* externalGenerator_ = nullptr;
 
 public:
  typedef std::shared_ptr<Sampler> shared_ptr;


  explicit Sampler(const noiseModel::Diagonal::shared_ptr& model,
                   uint_fast64_t seed = 42u);

  explicit Sampler(const noiseModel::Diagonal::shared_ptr& model,
                   std::mt19937_64& rng);

  explicit Sampler(const Vector& sigmas, uint_fast64_t seed = 42u);

  explicit Sampler(const Vector& sigmas, std::mt19937_64& rng);

 
  size_t dim() const { return model_->dim(); }
 
  Vector sigmas() const { return model_->sigmas(); }
 
  const noiseModel::Diagonal::shared_ptr& model() const { return model_; }


  Vector sample() const;

  template <typename T>
  T perturb(const T& value) const {
    return traits<T>::Retract(value, sample());
  }

  static Vector sampleDiagonal(const Vector& sigmas, std::mt19937_64* rng);
 
 protected:
  Vector sampleDiagonal(const Vector& sigmas) const;
};
 
}  // namespace gtsam