#include <alphaclusterednucleus.h>

Child of Nucleus for alpha clustered nuclei.

All options from the nucleus will still apply. The alpha-clustered nucleus adds new or updated features which are outlined below.

Definition at line 28 of file alphaclusterednucleus.h.

Inheritance diagram for smash::AlphaClusteredNucleus:

Public Member Functions
	AlphaClusteredNucleus (Configuration &config, int n_test, bool automatic)
	Constructor which takes a configuration and the number of test particles. More...

ThreeVector	distribute_nucleon () override
	Alpha-clustering sampling routine. More...

void	scale_tetrahedron_vertex_positions (double side_length)
	Scales the tetrahedron vertex positions to have the specified side length. More...

Public Member Functions inherited from smash::Nucleus
	Nucleus ()=default
	default constructor More...

	Nucleus (Configuration &config, int nTest)
	Constructor for Nucleus, that needs the configuration parameters from the inputfile and the number of testparticles. More...

	Nucleus (const std::map< PdgCode, int > &particle_list, int nTest)
	Constructor which directly initializes the Nucleus with particles and respective counts. More...

virtual	~Nucleus ()=default

double	mass () const

double	woods_saxon (double x)
	Woods-Saxon distribution. More...

virtual void	arrange_nucleons ()
	Sets the positions of the nucleons inside a nucleus. More...

virtual void	set_parameters_automatic ()
	Sets the deformation parameters of the Woods-Saxon distribution according to the current mass number. More...

virtual void	generate_fermi_momenta ()
	Generates momenta according to Fermi motion for the nucleons. More...

void	boost (double beta_scalar)
	Boosts the nuclei into the computational frame, such that the nucleons have the appropriate momentum and the nuclei are lorentz-contracted. More...

void	fill_from_list (const std::map< PdgCode, int > &particle_list, int testparticles)
	Adds particles from a map PDG code => Number_of_particles_with_that_PDG_code to the nucleus. More...

void	shift (double z_offset, double x_offset, double simulation_time)
	Shifts the nucleus to correct impact parameter and z displacement. More...

virtual void	rotate ()
	Rotates the nucleus using the three euler angles phi, theta and psi. More...

void	copy_particles (Particles *particles)
	Copies the particles from this nucleus into the particle list. More...

size_t	size () const
	Number of numerical (=test-)particles in the nucleus: More...

size_t	number_of_particles () const
	Number of physical particles in the nucleus: More...

size_t	number_of_protons () const
	Number of physical protons in the nucleus: More...

FourVector	center () const
	Calculate geometrical center of the nucleus. More...

void	set_label (BelongsTo label)
	Sets target / projectile labels on nucleons. More...

void	align_center ()
	Shifts the nucleus so that its center is at (0,0,0) More...

virtual double	nucleon_density (double r, double, double) const
	Return the Woods-Saxon probability density for the given position. More...

virtual double	nucleon_density_unnormalized (double r, double, double) const
	Return the unnormalized Woods-Saxon distribution for the given position without deformation. More...

virtual double	calculate_saturation_density () const

virtual void	set_saturation_density (double density)
	Sets the saturation density of the nucleus. More...

std::vector< ParticleData >::iterator	begin ()
	For iterators over the particle list: More...

std::vector< ParticleData >::iterator	end ()
	For iterators over the particle list: More...

std::vector< ParticleData >::const_iterator	cbegin () const
	For const iterators over the particle list: More...

std::vector< ParticleData >::const_iterator	cend () const
	For const iterators over the particle list: More...

void	set_diffusiveness (double diffuse)
	Sets the diffusiveness of the nucleus. More...

double	get_diffusiveness () const

double	get_saturation_density () const

double	default_nuclear_radius ()
	Default nuclear radius calculated as: More...

void	set_nuclear_radius (double rad)
	Sets the nuclear radius. More...

double	get_nuclear_radius () const

void	set_orientation_from_config (Configuration &orientation_config)
	Set angles for rotation of the nucleus from config file. More...

Private Attributes
double	tetrahedron_side_length_
	Side length of the tetrahedron used for alpha-clustering. More...

std::vector< ThreeVector >	tetrahedron_vertex_positions_
	Positions of the vertices of the regular tetrahedron with center at (0,0,0) used for alpha-clustering. More...

int	tetrahedron_vertex_index_ = 0
	An index to iterate through the vertices of the tetrahedron. More...

Additional Inherited Members
Protected Member Functions inherited from smash::Nucleus
void	random_euler_angles ()
	Randomly generate Euler angles. More...

Protected Attributes inherited from smash::Nucleus
std::vector< ParticleData >	particles_
	Particles associated with this nucleus. More...

double	saturation_density_ = nuclear_density
	Saturation density of this nucleus. More...

double	euler_phi_ = 0.0
	The Euler angle phi of the three Euler angles used to apply rotations to the nucleus. More...

double	euler_theta_ = 0.0
	Euler angle theta. More...

double	euler_psi_ = 0.0
	Euler angle psi. More...

bool	random_rotation_ = false
	Whether the nucleus should be rotated randomly. More...

Constructor & Destructor Documentation

◆ AlphaClusteredNucleus()

smash::AlphaClusteredNucleus::AlphaClusteredNucleus	(	Configuration &	config,
		int	n_test,
		bool	automatic
	)

Constructor which takes a configuration and the number of test particles.

Parameters

[in]	config	the input configuration object
[in]	n_test	number of test particles
[in]	automatic	whether or not the alpha-clustering parameters should be set automatically

Definition at line 22 of file alphaclusterednucleus.cc.

     : Nucleus(config, n_test) {
   int A = Nucleus::number_of_particles();
   int Z = Nucleus::number_of_protons();
   if (A == 16 && Z == 8) {
     // Set the Woods-Saxon parameters to those of Helium
     set_diffusiveness(0.322);
     set_nuclear_radius(1.676);
   } else {
     throw std::domain_error(
         "Alpha-clustering is only implemented for oxygen nuclei. Please, check "
         "the 'Alpha_Clustered' section in your input file.");
   }
  
   /* NOTE: Here the Nucleus parent class has been initialised and the Projectile
    * or Target subsection could be already be entirely extracted. Therefore
    * unconditionally call here the is_about_projectile function might fail.
    * This has to be called where appropriate and repeating it is not a problem.
    */
   if (!automatic && has_projectile_or_target(config)) {
     const bool is_projectile = is_about_projectile(config);
     const auto &side_length_key = [&is_projectile]() {
       return is_projectile
                  ? InputKeys::modi_collider_projectile_alphaClustered_sideLength
                  : InputKeys::modi_collider_target_alphaClustered_sideLength;
     }();
     tetrahedron_side_length_ = config.take(side_length_key);
   }
   scale_tetrahedron_vertex_positions(tetrahedron_side_length_);
   if (has_projectile_or_target(config)) {
     const bool is_projectile = is_about_projectile(config);
     const auto &orientation_section = [&is_projectile]() {
       return is_projectile ? InputSections::m_c_p_orientation
                            : InputSections::m_c_t_orientation;
     }();
     if (config.has_section(orientation_section)) {
       Configuration sub_conf =
           config.extract_complete_sub_configuration(orientation_section);
       set_orientation_from_config(sub_conf);
     }
   }
 }

Member Function Documentation

◆ distribute_nucleon()

ThreeVector smash::AlphaClusteredNucleus::distribute_nucleon ( )

overridevirtual

Alpha-clustering sampling routine.

This routine samples the nucleon using the Woods-Saxon routine with parameters for Helium and shifts them towards one of the vertices of the tetrahedron

Returns: Resulting spatial position of the nucleon

Reimplemented from smash::Nucleus.

Definition at line 66 of file alphaclusterednucleus.cc.

                                                       {
   ThreeVector alpha_clustering_shift =
       tetrahedron_vertex_positions_[tetrahedron_vertex_index_ %
                                     tetrahedron_vertex_positions_.size()];
   tetrahedron_vertex_index_ += 1;
  
   return Nucleus::distribute_nucleon() + alpha_clustering_shift;
 }

◆ scale_tetrahedron_vertex_positions()

void smash::AlphaClusteredNucleus::scale_tetrahedron_vertex_positions ( double side_length )

Scales the tetrahedron vertex positions to have the specified side length.

Parameters

[in] side_length Side length to be used to scale the tetrahedron

Definition at line 75 of file alphaclusterednucleus.cc.

                         {
   for (auto &position : tetrahedron_vertex_positions_) {
     position = position / position.abs() * std::sqrt(6) / 4 * side_length;
   }
 }

Member Data Documentation

◆ tetrahedron_side_length_

double smash::AlphaClusteredNucleus::tetrahedron_side_length_

private

Initial value:

=
      InputKeys::modi_collider_projectile_alphaClustered_sideLength
          .default_value()

Side length of the tetrahedron used for alpha-clustering.

Note: The default is set to the default of the projectile key, although this class is instantiated for the target, too. However, this should be fine since the keys defaults are forced to be the same in the database.

Definition at line 64 of file alphaclusterednucleus.h.

◆ tetrahedron_vertex_positions_

std::vector<ThreeVector> smash::AlphaClusteredNucleus::tetrahedron_vertex_positions_

private

Initial value:

= {
      {1, 0.0, 0.0},
      {-1.0 / 3, std::sqrt(8) / 3, 0.0},
      {-1.0 / 3, -std::sqrt(8) / 6, std::sqrt(24) / 6},
      {-1.0 / 3, -std::sqrt(8) / 6, -std::sqrt(24) / 6}}

Positions of the vertices of the regular tetrahedron with center at (0,0,0) used for alpha-clustering.

Definition at line 71 of file alphaclusterednucleus.h.

◆ tetrahedron_vertex_index_

int smash::AlphaClusteredNucleus::tetrahedron_vertex_index_ = 0

private

An index to iterate through the vertices of the tetrahedron.

Used in the alpha-clustering sampling routine to shift every 4th nucleon to the same vertex.

Definition at line 82 of file alphaclusterednucleus.h.

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

src/include/smash/alphaclusterednucleus.h
src/alphaclusterednucleus.cc

Public Member Functions

Private Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ AlphaClusteredNucleus()

Member Function Documentation

◆ distribute_nucleon()

◆ scale_tetrahedron_vertex_positions()

Member Data Documentation

◆ tetrahedron_side_length_

◆ tetrahedron_vertex_positions_

◆ tetrahedron_vertex_index_