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#ifndef COSMOINTERFACE_MEASUREMENTS_STANDARDMEASURER_H
#define COSMOINTERFACE_MEASUREMENTS_STANDARDMEASURER_H

/* This file is part of CosmoLattice, available at www.cosmolattice.net .
   Copyright Daniel G. Figueroa, Adrien Florio, Francisco Torrenti and Wessel Valkenburg.
   Released under the MIT license, see LICENSE.md. */

// File info: Main contributor(s): Daniel G. Figueroa, Adrien Florio, Francisco Torrenti,  Year: 2020

#include "CosmoInterface/measurements/measurementsIO/measurementssaver.h"
#include "TempLat/lattice/algebra/operators/power.h"
#include "TempLat/lattice/measuringtools/averager.h"

namespace TempLat
{
  class MeansMeasurer
  {
  public:
    // Put public methods here. These should change very little over time.
    MeansMeasurer() = delete;

    // @label:meansmeasurer_measure
    template <typename S, typename Q, typename T> static void measure(MeasurementsSaver<T> &ms, S fld, Q mom, T t)
    {
      auto phi = average(fld);
      auto phi2 = average(pow<2>(fld));
      auto pi = average(mom);
      auto pi2 = average(pow<2>(mom));

      ms.addAverage(t);
      ms.addAverage(phi);
      ms.addAverage(pi);
      ms.addAverage(phi2);
      ms.addAverage(pi2);

      auto rmsPhi2 = phi2 - pow<2>(phi);
      auto rmsPi2 = pi2 - pow<2>(pi);

      // Sometimes, machine precision leads to imaginary rms.
      // We check for this explicitly and set it to zero when it happens
      ms.addAverage(rmsPhi2 > 0 ? sqrt(rmsPhi2) : 0); // rms(phi)
      ms.addAverage(rmsPi2 > 0 ? sqrt(rmsPi2) : 0);   // rms(pi)
    }
    // @endlabel

    // Header for average files of scalar fields (scalar singlets, complex scalars, and SU(2) doublets)
    static std::vector<std::string> header()
    {
      return {"t", "<phi>", "<pi>", "<phi^2>", "<pi^2>", "rms(phi)", "rms(pi)"};
    }

    // Header for average files of gauge fields (U(1) and SU(2) sectors)
    static std::vector<std::string> headerEB()
    {
      return {"t", "<|E|>", "<|B|>", "<|E|^2>", "<|B|^2>", "rms(|E|)", "rms(|B|)"};
    }
  };
} // namespace TempLat

#endif