celeritas::PolyEvaluator< T, N > Class Template Reference

Functor class to evaluate a polynomial. More...

#include <PolyEvaluator.hh>

Public Types
Type aliases
using	result_type = T
using	argument_type = T
using	ArrayT = Array< T, N+1 >

Public Member Functions
template<class... Ts>
CELER_CONSTEXPR_FUNCTION	PolyEvaluator (Ts... coeffs)
	Construct with the polynomial to evaluate.
CELER_CONSTEXPR_FUNCTION	PolyEvaluator (ArrayT const &coeffs)
	Construct from an array of data.
CELER_CONSTEXPR_FUNCTION T	operator() (T arg) const
	Evaluate the polynomial at the given value.

Detailed Description

template<class T, size_type N>
class celeritas::PolyEvaluator< T, N >

Functor class to evaluate a polynomial.

This is an efficient and foolproof way of storing and evaluating a polynomial expansion:

\[ f(x) = a_0 + x * (a_1 + x * (a_2 + ...)) \]

It replaces opaque expressions such as:

corr = (zeff * (real_type(1.84035e-4) * zeff - real_type(1.86427e-2))
         + real_type(1.41125));

with

corr = PolyEvaluator{1.41125, -1.86427e-2, 1.84035e-4}(zeff);

or, to use an explicit type without having to cast each coefficient:

using PolyQuad = PolyEvaluator<real_type, N>;
corr = PolyQuad{1.41125, -1.86427e-2, 1.84035e-4)(zeff);

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

• PolyEvaluator.hh