#include <dynamicfluidfinder.h>

Finder for dynamic fluidizations.

Loops through all particles and checks if they reach the energy density threshold. This happens at the end of every time step for all hadrons that participated in a fluidizable process. For string fragmentation products, fluidization happens only after the fraction of formation time of the particle, controlled by Formation_Time_Fraction.

Definition at line 32 of file dynamicfluidfinder.h.

Inheritance diagram for smash::DynamicFluidizationFinder:

Public Member Functions
	DynamicFluidizationFinder (const RectangularLattice< EnergyMomentumTensor > &lattice, const std::map< int32_t, double > &background, const InitialConditionParameters &ic_params)
	Construct finder for fluidization action. More...

ActionList	find_actions_in_cell (const ParticleList &search_list, double dt, double gcell_vol, const std::vector< FourVector > &beam_momentum) const override
	Find particles to fluidize, depending on the energy density around them. More...

ActionList	find_actions_with_neighbors (const ParticleList &, const ParticleList &, const double, const std::vector< FourVector > &) const override
	Ignore the neighbor search for fluidization. More...

ActionList	find_actions_with_surrounding_particles (const ParticleList &, const Particles &, double, const std::vector< FourVector > &) const override
	Ignore the surrounding searches for fluidization. More...

ActionList	find_final_actions (const Particles &, bool) const override
	No final actions after fluidizing. More...

bool	above_threshold (const ParticleData &pdata) const
	Determine if fluidization condition is satisfied. More...

bool	is_process_fluidizable (const ProcessType &type) const
	Checks if a given process type is in fluidizable_processes_. More...

Public Member Functions inherited from smash::ActionFinderInterface
virtual	~ActionFinderInterface ()=default

Private Attributes
const RectangularLattice< EnergyMomentumTensor > &	energy_density_lattice_
	Lattice where energy momentum tensor is computed. More...

const std::map< int32_t, double > &	background_
	Background energy density at positions of particles, using the id as key. More...

const double	energy_density_threshold_ = NAN
	Minimum energy density surrounding the particle to fluidize it. More...

const double	min_time_ = NAN
	Minimum time (in lab frame) in fm to allow fluidization. More...

const double	max_time_ = NAN
	Maximum time (in lab frame) in fm to allow fluidization. More...

const double	formation_time_fraction_ = NAN
	Fraction of formation time after which a particles can fluidize. More...

const int	fluid_cells_ = std::numeric_limits<int>::quiet_NaN()
	Number of cells to interpolate the energy density. More...

const FluidizableProcessesBitSet	fluidizable_processes_
	Processes that create a fluidizable particle. More...

Constructor & Destructor Documentation

◆ DynamicFluidizationFinder()

smash::DynamicFluidizationFinder::DynamicFluidizationFinder	(	const RectangularLattice< EnergyMomentumTensor > &	lattice,
		const std::map< int32_t, double > &	background,
		const InitialConditionParameters &	ic_params
	)

inline

Construct finder for fluidization action.

Parameters

[in]	lattice	Lattice used for the energy density interpolation
[in]	background	Background map between particle indices and the corresponding background energy density
[in]	ic_params	Parameters for dynamic fluidization

Note: energy_density_lattice and energy_density_background are both "in" parameters because the class stores references, but the values are non constant.

Definition at line 45 of file dynamicfluidfinder.h.

       : energy_density_lattice_{lattice},
         background_{background},
         energy_density_threshold_{ic_params.energy_density_threshold.value()},
         min_time_{ic_params.min_time.value()},
         max_time_{ic_params.max_time.value()},
         formation_time_fraction_{ic_params.formation_time_fraction.value()},
         fluid_cells_{ic_params.num_fluid_cells.value()},
         fluidizable_processes_{ic_params.fluidizable_processes.value()} {};

Member Function Documentation

◆ find_actions_in_cell()

ActionList smash::DynamicFluidizationFinder::find_actions_in_cell	(	const ParticleList &	search_list,
		double	dt,
		double	gcell_vol,
		const std::vector< FourVector > &	beam_momentum
	)		const

overridevirtual

Find particles to fluidize, depending on the energy density around them.

Parameters

[in]	search_list	List of candidate particles to fluidize.
[in]	dt	Time step duration in fm.
[in]	gcell_vol	Volume of the grid cell in fm³,
[in]	beam_momentum	Unused.

Returns: List of fluidization actions that will happen at the corresponding formation time.

Implements smash::ActionFinderInterface.

Definition at line 18 of file dynamicfluidfinder.cc.

                                                                        {
   ActionList actions;
  
   for (const ParticleData &p : search_list) {
     const double t0 = p.position().x0();
     const double t_end = t0 + dt;
     if (t_end < min_time_ || t0 > max_time_) {
       break;
     }
     const double fluidization_time =
         t0 + formation_time_fraction_ * (p.formation_time() - t0);
     if (fluidization_time < t_end) {
       if (is_process_fluidizable(p.get_history().process_type)) {
         if (above_threshold(p)) {
           double time_until = (1 - p.xsec_scaling_factor() <= really_small)
                                   ? 0
                                   : fluidization_time - t0;
           actions.emplace_back(
               std::make_unique<FluidizationAction>(p, p, time_until));
         }
       }
     }
   }  // search_list loop
   return actions;
 }

◆ find_actions_with_neighbors()

ActionList smash::DynamicFluidizationFinder::find_actions_with_neighbors	(	const ParticleList &	,
		const ParticleList &	,
		const double	,
		const std::vector< FourVector > &
	)		const

inlineoverridevirtual

Ignore the neighbor search for fluidization.

Implements smash::ActionFinderInterface.

Definition at line 72 of file dynamicfluidfinder.h.

                                                     {
     return {};
   }

◆ find_actions_with_surrounding_particles()

ActionList smash::DynamicFluidizationFinder::find_actions_with_surrounding_particles	(	const ParticleList &	,
		const Particles &	,
		double	,
		const std::vector< FourVector > &
	)		const

inlineoverridevirtual

Ignore the surrounding searches for fluidization.

Implements smash::ActionFinderInterface.

Definition at line 79 of file dynamicfluidfinder.h.

                                                     {
     return {};
   }

◆ find_final_actions()

ActionList smash::DynamicFluidizationFinder::find_final_actions	(	const Particles &	,
		bool
	)		const

inlineoverridevirtual

No final actions after fluidizing.

Implements smash::ActionFinderInterface.

Definition at line 86 of file dynamicfluidfinder.h.

                                                                         {
     return {};
   }

◆ above_threshold()

bool smash::DynamicFluidizationFinder::above_threshold ( const ParticleData & pdata ) const

Determine if fluidization condition is satisfied.

Parameters

[in] pdata Particle to be checked for fluidization.

Returns: Whether energy density around pdata is high enough.

Definition at line 47 of file dynamicfluidfinder.cc.

                                      {
   EnergyMomentumTensor Tmunu;
   // value_at returns false if pdata is out of bounds
   const bool inside =
       energy_density_lattice_.value_at(pdata.position().threevec(), Tmunu);
   if (inside) {
     // If the particle is not in the map, the background evaluates to 0
     const double background =
         background_.count(pdata.id()) ? background_.at(pdata.id()) : 0;
     const double e_den_particles =
         Tmunu.boosted(Tmunu.landau_frame_4velocity())[0];
     if (e_den_particles + background >= energy_density_threshold_) {
       logg[LFluidization].debug()
           << "Fluidize " << pdata.id() << " with " << e_den_particles << "+"
           << background << " GeV/fm^3 at " << pdata.position().x0()
           << " fm, formed at " << pdata.formation_time() << " fm";
       return true;
     }
   }
   return false;
 }

◆ is_process_fluidizable()

bool smash::DynamicFluidizationFinder::is_process_fluidizable ( const ProcessType & type ) const

Checks if a given process type is in fluidizable_processes_.

In particular, initially sampled hadrons are not fluidizable and have ProcessType::None, which falls in the default case for the switch.

Returns: whether the process is fluidizable

Definition at line 70 of file dynamicfluidfinder.cc.

                                    {
   if (is_string_soft_process(type)) {
     return fluidizable_processes_
         [IncludedFluidizableProcesses::From_SoftString];
   }
   switch (type) {
     case ProcessType::Elastic:
       return fluidizable_processes_[IncludedFluidizableProcesses::From_Elastic];
       break;
     case ProcessType::Decay:
       return fluidizable_processes_[IncludedFluidizableProcesses::From_Decay];
       break;
     case ProcessType::TwoToOne:
     case ProcessType::TwoToTwo:
     case ProcessType::TwoToThree:
     case ProcessType::TwoToFour:
     case ProcessType::TwoToFive:
     case ProcessType::MultiParticleThreeMesonsToOne:
     case ProcessType::MultiParticleThreeToTwo:
     case ProcessType::MultiParticleFourToTwo:
     case ProcessType::MultiParticleFiveToTwo:
       return fluidizable_processes_
           [IncludedFluidizableProcesses::From_Inelastic];
       break;
     case ProcessType::StringHard:
       return fluidizable_processes_
           [IncludedFluidizableProcesses::From_HardString];
       break;
     default:
       return false;
   }
   return false;
 }

Member Data Documentation

◆ energy_density_lattice_

const RectangularLattice<EnergyMomentumTensor>& smash::DynamicFluidizationFinder::energy_density_lattice_

private

Lattice where energy momentum tensor is computed.

Note: It must be a reference so that it can be updated outside the class, without creating a new Finder object.

Definition at line 114 of file dynamicfluidfinder.h.

◆ background_

const std::map<int32_t, double>& smash::DynamicFluidizationFinder::background_

private

Background energy density at positions of particles, using the id as key.

Note: It is a reference so that it can be updated outside the class, e.g. by an external manager using SMASH as a library.

Definition at line 121 of file dynamicfluidfinder.h.

◆ energy_density_threshold_

const double smash::DynamicFluidizationFinder::energy_density_threshold_ = NAN

private

Minimum energy density surrounding the particle to fluidize it.

Definition at line 123 of file dynamicfluidfinder.h.

◆ min_time_

const double smash::DynamicFluidizationFinder::min_time_ = NAN

private

Minimum time (in lab frame) in fm to allow fluidization.

Definition at line 125 of file dynamicfluidfinder.h.

◆ max_time_

const double smash::DynamicFluidizationFinder::max_time_ = NAN

private

Maximum time (in lab frame) in fm to allow fluidization.

Definition at line 127 of file dynamicfluidfinder.h.

◆ formation_time_fraction_

const double smash::DynamicFluidizationFinder::formation_time_fraction_ = NAN

private

Fraction of formation time after which a particles can fluidize.

Definition at line 129 of file dynamicfluidfinder.h.

◆ fluid_cells_

const int smash::DynamicFluidizationFinder::fluid_cells_ = std::numeric_limits<int>::quiet_NaN()

private

Number of cells to interpolate the energy density.

Definition at line 131 of file dynamicfluidfinder.h.

◆ fluidizable_processes_

const FluidizableProcessesBitSet smash::DynamicFluidizationFinder::fluidizable_processes_

private

Processes that create a fluidizable particle.

Definition at line 133 of file dynamicfluidfinder.h.

The documentation for this class was generated from the following files:

src/include/smash/dynamicfluidfinder.h
src/dynamicfluidfinder.cc

Public Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ DynamicFluidizationFinder()

Member Function Documentation

◆ find_actions_in_cell()

◆ find_actions_with_neighbors()

◆ find_actions_with_surrounding_particles()

◆ find_final_actions()

◆ above_threshold()

◆ is_process_fluidizable()

Member Data Documentation

◆ energy_density_lattice_

◆ background_

◆ energy_density_threshold_

◆ min_time_

◆ max_time_

◆ formation_time_fraction_

◆ fluid_cells_

◆ fluidizable_processes_