tomoproblem.h

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/* This file is part of the Tomographer project, which is distributed under the
 * terms of the MIT license.
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2015 ETH Zurich, Institute for Theoretical Physics, Philippe Faist
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef TOMOPROBLEM_H
#define TOMOPROBLEM_H

namespace Tomographer {


template<typename MatrQ_, typename LLHValueType_ = double, bool UseCLoopInstead = false>
struct IndepMeasTomoProblem
{
  typedef MatrQ_ MatrQ;
  typedef LLHValueType_ LLHValueType;

  const MatrQ matq;

  const int dim;
  const int dim2;
  const int Ndof;

  LLHValueType NMeasAmplifyFactor;

  typename MatrQ::VectorParamListType Exn;
  typename MatrQ::FreqListType Nx;

  typename MatrQ::MatrixType rho_MLE;

  typename MatrQ::MatrixType T_MLE;
  typename MatrQ::VectorParamType x_MLE;

  IndepMeasTomoProblem(MatrQ matq_)
    : matq(matq_),
      dim(matq_.dim()),
      dim2(dim*dim),
      Ndof(dim2 - 1),
      NMeasAmplifyFactor(1),
      rho_MLE(matq.initMatrixType()),
      T_MLE(matq.initMatrixType()),
      x_MLE(matq.initVectorParamType())
  {
    // NOTE: Exn & N are left uninitialized, because we don't yet know how many POVM
    // effects there will be. (That will probably be read from a MAT file or such...)
    assert(MatrQ::FixedDim == Eigen::Dynamic || MatrQ::FixedDim == (int)matq.dim());
  }

  inline LLHValueType calc_llh(const typename MatrQ::VectorParamType & x) const;
};



namespace tomo_internal
{
  template<typename MatrQ, typename LLHValueType, bool UseCLoopInstead>
  struct LLH_Calculator
  {
    static inline LLHValueType calc_llh(const IndepMeasTomoProblem<MatrQ,LLHValueType,UseCLoopInstead> *data,
                                        const typename MatrQ::VectorParamType & x)
    {
      return -2 * data->NMeasAmplifyFactor * (
          data->Nx.template cast<LLHValueType>() * (data->Exn * x).array().log()
          ).sum();
    }
  };

  //
  // Specialization of helper for implementing the C for loop instead.
  //
  // no doxygen doc needed.
  //
  template<typename MatrQ, typename LLHValueType>
  struct LLH_Calculator<MatrQ, LLHValueType, true>
  {
    static inline LLHValueType calc_llh(const IndepMeasTomoProblem<MatrQ,LLHValueType,true> *data,
                                        const typename MatrQ::VectorParamType & x)
    {
      std::size_t k;
      typename MatrQ::RealScalar val = 0;
      for (k = 0; k < (std::size_t)data->Exn.rows(); ++k) {
        const typename MatrQ::RealScalar thisval = (data->Exn.row(k) * x);
        //std::cout << "k = "<<k<<"; thisval = "<<thisval << "\n";
        val += data->Nx[k] * std::log(thisval);
      }
      //std::cout << "val = " << val << "\n\n";
      return -2 * data->NMeasAmplifyFactor * val;
    }
  };
}


template<typename MatrQ, typename LLHValueType, bool UseCLoopInstead>
inline LLHValueType IndepMeasTomoProblem<MatrQ, LLHValueType, UseCLoopInstead>::calc_llh(
    const typename MatrQ::VectorParamType & x
    ) const
{
  return tomo_internal::LLH_Calculator<MatrQ, LLHValueType, UseCLoopInstead>::calc_llh(this, x);
}





} // namespace Tomographer



#endif