Detailed Description

template<typename T = double>
class MathLib::PiecewiseConstantInterpolation< T >

This class implements a one dimensional piecewise constant interpolation algorithm.

Definition at line 26 of file PiecewiseConstantInterpolation.h.

#include <PiecewiseConstantInterpolation.h>

Public Member Functions
	PiecewiseConstantInterpolation (std::vector< T > const &supporting_points, std::vector< double > const &values_at_supp_pnts)
double	value (double const pnt_to_interpolate) const
	Calculates the interpolation value.

Private Attributes
std::vector< T > const &	supp_pnts_
std::vector< double > const &	values_at_supp_pnts_

Constructor & Destructor Documentation

◆ PiecewiseConstantInterpolation()

template<typename T = double>

MathLib::PiecewiseConstantInterpolation< T >::PiecewiseConstantInterpolation	(	std::vector< T > const &	supporting_points,
		std::vector< double > const &	values_at_supp_pnts )

inline

The constructor stores the vector of supporting points \((x_0, x_1, \dots, x_n)\) and the entries of the vector of values at the supporting points \((y_0, y_1, \dots, y_n)\) where \(n\) is the number of entries of the vector. The number of supporting points must be equal to the number of values at the supporting points. It is assumed that \(x_j\) corresponds to \(y_j\) for all \(j \in [0, n]\).

Furthermore, it is assumed that the supporting points are sorted, i.e. \(x_0 < x_1 < \dots < x_n\).

Parameters

supporting_points	vector of supporting points
values_at_supp_pnts	vector of values at the supporting points one can set the switch to true

Definition at line 44 of file PiecewiseConstantInterpolation.h.

        : supp_pnts_(supporting_points),
          values_at_supp_pnts_(values_at_supp_pnts)
    {
        if (supp_pnts_.size() != values_at_supp_pnts_.size())
        {
            OGS_FATAL(
                "Inconsistent data given to PiecewiseConstantInterpolation, "
                "number of given supporting points is {}, number of given "
                "values is {}.",
                supp_pnts_.size(), values_at_supp_pnts_.size());
        }
        if (supp_pnts_.empty())
        {
            ERR("PiecewiseConstantInterpolation: passed empty vector.");
        }
    }

References supp_pnts_, and values_at_supp_pnts_.

Member Function Documentation

◆ value()

template<typename T = double>

double MathLib::PiecewiseConstantInterpolation< T >::value ( double const pnt_to_interpolate ) const

inline

Calculates the interpolation value.

Parameters

pnt_to_interpolate The point the interpolation value is calculated for. If the pnt_to_interpolate is outside the interval \([x_{\min}, x_{\max}]\), where \(x_{\min} = \min_{1 \le j \le n} x_j\) and \(x_{\max} = \max_{1 \le j \le n} x_j\). If point_to_interpolate is smaller than \(x_{\min}\) then \(y_{\min}\) is returned. Analogously, if the point_to_interpolate is greater than \(x_{\max}\) then \(y_{\max}\) is returned.

Returns: The interpolated value.

Definition at line 76 of file PiecewiseConstantInterpolation.h.

    {
        if (pnt_to_interpolate <= supp_pnts_.front())
        {
            return values_at_supp_pnts_.front();
        }
 
        if (supp_pnts_.back() <= pnt_to_interpolate)
        {
            return values_at_supp_pnts_.back();
        }
 
        auto const& it(std::upper_bound(supp_pnts_.begin(), supp_pnts_.end(),
                                        pnt_to_interpolate));
        // Here access the iterator it without checking is okay since the
        // corner cases are checked above.
        auto const interval_idx = std::distance(supp_pnts_.begin(), it) - 1;
 
        return values_at_supp_pnts_[interval_idx];
    }