MARLEY (Model of Argon Reaction Low Energy Yields)  v1.0.0
A Monte Carlo event generator for tens-of-MeV neutrino-nucleus interactions in liquid argon
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marley::InterpolationGrid< FirstNumericType, SecondNumericType > Class Template Reference

One-dimensional function y(x) defined using a grid of ordered pairs (x,y) and an interpolation rule. More...

#include <InterpolationGrid.hh>

Public Types

enum  ExtrapolationMethod { Zero, Endpoint, Continue, Throw }
 Method to use for computing y(x) when the x value lies beyond the grid boundaries. More...
 
using Grid = std::vector< OrderedPair >
 
using GridConstIterator = typename std::vector< OrderedPair >::const_iterator
 
enum  InterpolationMethod {
  Constant = 1, LinearLinear = 2, LinearLog = 3, LogLinear = 4,
  LogLog = 5
}
 Method to use for interpolating between (x,y) grid points. More...
 
using OrderedPair = std::pair< FirstNumericType, SecondNumericType >
 

Public Member Functions

 InterpolationGrid (InterpolationMethod interp_method=InterpolationMethod::LinearLinear, ExtrapolationMethod extrap_method=ExtrapolationMethod::Zero)
 Create an InterpolationGrid without any grid points.
 
 InterpolationGrid (const Grid &grid, InterpolationMethod interp_method=InterpolationMethod::LinearLinear, ExtrapolationMethod extrap_method=ExtrapolationMethod::Zero)
 Create an InterpolationGrid from a vector of ordered pairs. More...
 
 InterpolationGrid (const std::vector< FirstNumericType > &xs, const std::vector< SecondNumericType > &ys, InterpolationMethod interp_method=InterpolationMethod::LinearLinear, ExtrapolationMethod extrap_method=ExtrapolationMethod::Zero)
 Create an InterpolationGrid from vectors of x and y values.
 
OrderedPair & at (size_t j)
 Get a reference to the jth ordered pair from the grid.
 
const OrderedPair & back () const
 Returns a reference to the last ordered pair.
 
void clear ()
 Delete all ordered pairs from the grid.
 
ExtrapolationMethod extrapolation_method () const
 Get the ExtrapolationMethod used by this InterpolationGrid.
 
const OrderedPair & front () const
 Returns a reference to the first ordered pair.
 
std::function
< SecondNumericType(FirstNumericType)> 
get_interpolating_function ()
 Get a std::function object that represents y(x) for this InterpolationGrid.
 
void insert (FirstNumericType x, SecondNumericType y)
 Add a new ordered pair (x, y) to the grid.
 
SecondNumericType interpolate (FirstNumericType x) const
 Compute y(x) using the current InterpolationMethod.
 
InterpolationMethod interpolation_method () const
 Get the InterpolationMethod used by this InterpolationGrid.
 
GridConstIterator lower_bound (const GridConstIterator &begin, const GridConstIterator &end, FirstNumericType x) const
 Returns a const_iterator to the first element of the grid for which the x value is not less than (i.e. greater than or equal to) x.
 
void set_interpolationMethod (InterpolationMethod method)
 Set the InterpolationMethod to use.
 
void set_interpolationMethod (ExtrapolationMethod method)
 Set the ExtrapolationMethod to use.
 
size_t size () const
 Get the number of ordered pairs on the grid.
 
GridConstIterator upper_bound (const GridConstIterator &begin, const GridConstIterator &end, FirstNumericType x) const
 Returns a const_iterator to the first element of the grid for which the x value is greater than x.
 

Detailed Description

template<typename FirstNumericType, typename SecondNumericType = FirstNumericType>
class marley::InterpolationGrid< FirstNumericType, SecondNumericType >

One-dimensional function y(x) defined using a grid of ordered pairs (x,y) and an interpolation rule.

This class implements the one-dimensional interpolation rules described in the ENDF-6 formats manual for a grid of (x,y) pairs.

Template Parameters
FirstNumericTypetype for the x values
SecondNumericTypetype for the y values

Member Enumeration Documentation

template<typename FirstNumericType, typename SecondNumericType = FirstNumericType>
enum marley::InterpolationGrid::ExtrapolationMethod

Method to use for computing y(x) when the x value lies beyond the grid boundaries.

The table below describes how y(x) is calculated using each of the allowed ExtrapolationMethod settings. In the notation used below, the lowest x value is called \(x_\text{left}\), the greatest x value is called \(x_\text{right}\), and their corresponding y values are called \(y_\text{left}\) and \(y_\text{right}\), respectively. The ExtrapolationMethod is only relevant when \(x < x_\text{left}\) or \(x > x_\text{right}\).

Extrapolation Methods
MethodDescription
Zero\(y = 0\)
Endpoint\(y = \begin{cases} y_\text{left} & x < x_\text{left} \newline y_\text{right} & x > x_\text{right} \end{cases}\)
ContinueUse the usual InterpolationMethod formula with
\(y = \begin{cases} y_1 = y_\text{left} \text{ and } y_2 = y_{\text{left}+1} & x < x_\text{left} \newline y_1 = y_{\text{right}-1} \text{ and } y_2 = y_\text{right} & x > x_\text{right} \end{cases}\)
where \(y_{\text{left}+1}\) is the y value corresponding to the second-lowest x value, and \(y_{\text{right}-1}\) is the y value corresponding to the second-highest x value.
template<typename FirstNumericType, typename SecondNumericType = FirstNumericType>
enum marley::InterpolationGrid::InterpolationMethod

Method to use for interpolating between (x,y) grid points.

For \(x_1 \leq x < x_2\), the table below describes how the corresponding y value is calculated using each of the allowed InterpolationMethod settings.

Interpolation Methods
MethodDescription
Constant\(y = y_1\)
LinearLinear\(y = y_1 + \frac{y_2 - y_1}{x_2 - x_1}(x - x_1) \)
LinearLog\(y = \exp\left[\ln(y_1) + \frac{\ln(y_2) - \ln(y_1)}{x_2 - x_1}(x - x_1)\right] \)
LogLinear\(y = y_1 + \frac{y_2 - y_1}{\ln[x_2] - \ln[x_1]}[\ln(x) - \ln(x_1)] \)
LogLog\(y = \exp\left[\ln(y_1) + \frac{\ln(y_2) - \ln(y_1)}{\ln(x_2) - \ln(x_1)}(\ln[x] - \ln[x_1])\right] \)

Constructor & Destructor Documentation

template<typename FirstNumericType, typename SecondNumericType = FirstNumericType>
marley::InterpolationGrid< FirstNumericType, SecondNumericType >::InterpolationGrid ( const Grid &  grid,
InterpolationMethod  interp_method = InterpolationMethod::LinearLinear,
ExtrapolationMethod  extrap_method = ExtrapolationMethod::Zero 
)
inline

Create an InterpolationGrid from a vector of ordered pairs.

Todo:
Add error checks for the supplied grid

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