marley::CachedOpticalModel Class Reference

Nuclear optical model that caches transmission coefficient calculations for efficiency. More...

#include <CachedOpticalModel.hh>

Inheritance diagram for marley::CachedOpticalModel:

Classes
struct	TCKey

Public Member Functions
	CachedOpticalModel (int Z, int A)
virtual double	transmission_coefficient (double total_KE_CM, int fragment_pdg, int two_j, int l, int two_s, int target_charge=0) override
	Calculate the transmission coefficient for a nuclear fragment.
Public Member Functions inherited from marley::OpticalModel
	OpticalModel (int Z, int A)
int	A () const
	Get the mass number.
virtual std::complex< double >	optical_model_potential (double r, double fragment_KE_lab, int fragment_pdg, int two_j, int l, int two_s, int target_charge=0)=0
	Calculate the optical model potential (including the Coulomb potential)
virtual void	print (std::ostream &out) const =0
	Print information about the optical model parameters.
virtual double	total_cross_section (double fragment_KE_lab, int fragment_pdg, int two_s, size_t l_max, int target_charge=0)=0
	Compute the energy-averaged total cross section (MeV -2) for a nuclear fragment projectile.
int	Z () const
	Get the atomic number.

Static Public Member Functions
static void	set_use_cache (bool use_it)

Protected Member Functions
virtual double	compute_transmission_coefficient (double total_KE_CM, int fragment_pdg, int two_j, int l, int two_s, int target_charge=0)=0
	Do the actual calculation of the transmission coefficient.

Protected Attributes
std::map< TCKey, std::shared_ptr< InterpolatingFunction > >	tc_cache_
	Saved InterpolatingFunction objects corresponding to previously-encountered transmission coefficient requests.
Protected Attributes inherited from marley::OpticalModel
int	A_
int	Z_

Static Protected Attributes
static constexpr double	MAX_TOTAL_KE_CM = 100.
	Maximum kinetic energy to use when interacting with the cache.
static constexpr double	MIN_TOTAL_KE_CM = 1e-10
	Minimum kinetic energy to use when interacting with the cache.
static bool	USE_CACHE = true
	Boolean switch that allows global enabling/disabling of the cache, which is used by default.

Detailed Description

Nuclear optical model that caches transmission coefficient calculations for efficiency.

Definition at line 33 of file CachedOpticalModel.hh.

Constructor & Destructor Documentation

CachedOpticalModel()

marley::CachedOpticalModel::CachedOpticalModel ( int Z, int A )

inline

Parameters

Z	Atomic number of the desired nuclide
A	Mass number of the desired nuclide

Definition at line 39 of file CachedOpticalModel.hh.

: OpticalModel( Z, A ) {}

References marley::OpticalModel::OpticalModel(), marley::OpticalModel::A(), and marley::OpticalModel::Z().

Referenced by marley::KoningDelarocheOpticalModel::KoningDelarocheOpticalModel().

Member Function Documentation

set_use_cache()

static void marley::CachedOpticalModel::set_use_cache ( bool use_it )

inlinestatic

Definition at line 82 of file CachedOpticalModel.hh.

                                                      {
        USE_CACHE = use_it;
      }

transmission_coefficient()

double marley::CachedOpticalModel::transmission_coefficient ( double total_KE_CM, int fragment_pdg, int two_j, int l, int two_s, int target_charge = 0 )

overridevirtual

Calculate the transmission coefficient for a nuclear fragment.

Parameters

total_KE_CM	Total CM frame kinetic energy (MeV)
fragment_pdg	PDG code of the fragment
two_j	Two times the total angular momentum of the fragment
l	Orbital angular momentum of the fragment
two_s	Two times the spin of the fragment
target_charge	Net charge of the target atom

Implements marley::OpticalModel.

Definition at line 23 of file CachedOpticalModel.cc.

{
  // If we're in the region of kinetic energies where we use the cache, then
  // check whether we've encountered this combination of quantum numbers before
  if ( USE_CACHE && total_KE_CM >= MIN_TOTAL_KE_CM
    && total_KE_CM <= MAX_TOTAL_KE_CM )
  {
    TCKey temp_key( fragment_pdg, two_j, l, two_s, target_charge );
    const auto cache_iter = tc_cache_.find( temp_key );
 
    // If we can find a match in the cache, evaluate the transmission
    // coefficient value using the stored interpolating function
    if ( cache_iter != tc_cache_.cend() ) {
      return cache_iter->second->evaluate( total_KE_CM );
    }
 
    // Otherwise, create an interpolating function object over the caching
    // kinetic energy range
    std::function< double(double) > t_coeff = [ this, fragment_pdg, two_j,
      l, two_s, target_charge ]( double tot_KE_CM ) -> double
    {
      return this->compute_transmission_coefficient( tot_KE_CM, fragment_pdg,
        two_j, l, two_s, target_charge );
    };
 
    auto t_coeff_interp = std::make_shared<
      marley::LinearInterpolatingFunction >( t_coeff, MIN_TOTAL_KE_CM,
        MAX_TOTAL_KE_CM, marley::DEFAULT_N_LINEAR );
 
    // Compute the interpolated transmission coefficient for the current
    // call to this function
    double tc_result = t_coeff_interp->evaluate( total_KE_CM );
 
    // Add the completed interpolating function to the cache before returning
    // the current result
    tc_cache_[ temp_key ] = std::move( t_coeff_interp );
    return tc_result;
  }
 
  // If we're outside the caching energy range, just compute the transmission
  // coefficient without relying on the cache at all
  return this->compute_transmission_coefficient( total_KE_CM, fragment_pdg,
    two_j, l, two_s, target_charge );
}

References compute_transmission_coefficient(), marley::LinearInterpolatingFunction::evaluate(), MAX_TOTAL_KE_CM, MIN_TOTAL_KE_CM, tc_cache_, and USE_CACHE.

Member Data Documentation

MAX_TOTAL_KE_CM

double marley::CachedOpticalModel::MAX_TOTAL_KE_CM = 100.

staticconstexprprotected

Maximum kinetic energy to use when interacting with the cache.

Definition at line 101 of file CachedOpticalModel.hh.

Referenced by transmission_coefficient().

MIN_TOTAL_KE_CM

double marley::CachedOpticalModel::MIN_TOTAL_KE_CM = 1e-10

staticconstexprprotected

Minimum kinetic energy to use when interacting with the cache.

Definition at line 99 of file CachedOpticalModel.hh.

Referenced by transmission_coefficient().

tc_cache_

std::map< TCKey, std::shared_ptr< InterpolatingFunction > > marley::CachedOpticalModel::tc_cache_

protected

Saved InterpolatingFunction objects corresponding to previously-encountered transmission coefficient requests.

Definition at line 96 of file CachedOpticalModel.hh.

Referenced by transmission_coefficient().

USE_CACHE

bool marley::CachedOpticalModel::USE_CACHE = true

staticprotected

Boolean switch that allows global enabling/disabling of the cache, which is used by default.

Definition at line 105 of file CachedOpticalModel.hh.

Referenced by transmission_coefficient().

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

• /home/sjg/Desktop/marley/include/marley/CachedOpticalModel.hh
• /home/sjg/Desktop/marley/src/CachedOpticalModel.cc