File hubbleconstraint.h

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#ifndef COSMOINTERFACE_HELPERS_HUBBLELAWS_H
#define COSMOINTERFACE_HELPERS_HUBBLELAWS_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 "TempLat/lattice/algebra/operators/operators.h"
#include "CosmoInterface/definitions/energies.h"
#include "TempLat/util/templatvector.h"

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

    // This function computes the degree of conservation of the 1st Friedmann equation (H^2 \propto \rho).
    template <class Model> static auto get(Model &model)
    {
      auto rho = Energies::rho(model);

      auto LHS = pow<2>(model.aDotI);                                                              // left hand side
      auto RHS = pow(model.aI, 2 * model.alpha + 2) / 3. * pow<2>(model.fStar / Model::MPl) * rho; // right hand side

      // Returns a vector, whose 0 component is the relative degree of conservation.
      return make_templatvector((LHS - RHS) / (LHS + RHS), LHS, RHS);
    }
  };
} // namespace TempLat

#endif