dcdm_wdm_species.h

#pragma once
#include <memory>
#include <string_view>
#include <vector>
 
#include "background.h"
#include "composite_species.h"
#include "dcdm.h"
#include "species/shooting_target.h"
#include "species/species_build_context.h"
#include "wdm_decay_product.h"
 
class BackgroundModule;
 
class DCDM_WDM_Species : public CompositeSpecies {
 public:
  static constexpr std::string_view kTypeName = "dcdm_wdm";
 
  // Uses the generic CompositeSpecies::PerturbLayout (one owning sub-layout per
  // child in children_ order) — required by the TallyStressEnergy/DelegateTally
  // hot path (#358). Typed views below.
  enum ChildIndex { kDcdm = 0, kWdm = 1 };
  static const DCDMSpecies::PerturbLayout& dcdm_layout(const BaseSpecies::PerturbLayout& my) {
    return static_cast<const DCDMSpecies::PerturbLayout&>(
        *static_cast<const CompositeSpecies::PerturbLayout&>(my).child_layouts[kDcdm]);
  }
  static const NCDMBaseSpecies::PerturbLayout& wdm_layout(const BaseSpecies::PerturbLayout& my) {
    return static_cast<const NCDMBaseSpecies::PerturbLayout&>(
        *static_cast<const CompositeSpecies::PerturbLayout&>(my).child_layouts[kWdm]);
  }
 
  DCDM_WDM_Species(std::unique_ptr<WdmDecayProductSpecies> wdm,
                   const background* pba,
                   const BackgroundModule* bgm,
                   double omega0_combined,
                   double Omega_ini_dcdm);
 
  static std::vector<Named> CreateAll(const SpeciesBuildContext& ctx);
 
  void SetBackgroundModule(const BackgroundModule* bgm) override;
 
  // Injection wiring (see class doc)
  void ComputeBackground(double a, const double* pvecback_B, double* pvecback) override;
  void BackgroundDerivs(double tau, const double* y, double* dy, const double* pvecback) override;
 
  void WriteBackgroundColumnTitles(BackgroundColumnWriter& w) const override;
  void WriteBackgroundData(const double* pvecback, BackgroundColumnWriter& w) const override;
 
  double GetOmega0() const override;
 
  // ── Shooter hooks ──────────────────────────────────────────────────────────
  std::vector<ShootingTarget> GetShootingTargets() const override;
  void ComputeShootingGuess(const SpeciesBuildContext& ctx,
                            std::vector<double>& guess,
                            std::vector<double>& dxdy) const override;
  double ComputeShootingResidual(const ShootingResidualContext& ctx,
                                 const ShootingTarget& target) const override;
 
  // ── Perturbations ──────────────────────────────────────────────────────────
  // Registration, derivs (children + AddCouplingDerivs), ICs, stress-energy and
  // switch copies use the generic CompositeSpecies child loops. FillSources is
  // overridden to also write the parent's transfer sources (DCDMSpecies itself
  // has none — mirrors DCDM_DR).
  void FillSources(const BaseSpecies::PerturbLayout& layout,
                   const double* y,
                   const double* dy,
                   PerturbSourceContext& ctx) const override;
  void WriteOutputColumns(
      PerturbColumnWriter& writer,
      const PerturbationsModule& mod,
      file_format fmt,
      TransferColumnSection section = TransferColumnSection::all) const override;
 
  DCDMSpecies& dcdm() {
    return *dcdm_;
  }
  const DCDMSpecies& dcdm() const {
    return *dcdm_;
  }
  WdmDecayProductSpecies& wdm() {
    return *wdm_;
  }
  const WdmDecayProductSpecies& wdm() const {
    return *wdm_;
  }
 
 protected:
  void AddCouplingDerivs(double tau,
                         const double* y,
                         double* dy,
                         const perturb_parameters_and_workspace& ppaw) const override;
 
 private:
  DCDMSpecies* dcdm_           = nullptr;  // non-owning pointers into children_
  WdmDecayProductSpecies* wdm_ = nullptr;
  const background* pba_;
  const BackgroundModule* bgm_ = nullptr;
 
  ShootingTarget shooting_target_{};
  bool needs_shooting_ = false;
 
  // Scratch for BackgroundDerivs (background integration is single-threaded).
  mutable std::vector<double> scratch_J_, scratch_dJ_;
};