celeritas::SoftEqual< RealType > Class Template Reference

Functor for noninfinite floating point equality. More...

#include <SoftEqual.hh>

Public Types
Type aliases
using	value_type = RealType

Public Member Functions
constexpr	SoftEqual ()
	Construct with default relative/absolute precision.
	SoftEqual (value_type rel)
	Construct with scaled absolute precision.
	SoftEqual (value_type rel, value_type abs)
	Construct with both relative and absolute precision.
bool	operator() (value_type a, value_type b) const
	Compare two values, implicitly casting arguments.
constexpr value_type	rel () const
	Relative allowable error.
constexpr value_type	abs () const
	Absolute tolerance.

Detailed Description

template<class RealType = ::celeritas::real_type>
class celeritas::SoftEqual< RealType >

Functor for noninfinite floating point equality.

This function-like class considers an absolute tolerance for values near zero, and a relative tolerance for values far from zero. It correctly returns "false" if either value being compared is NaN. The call operator is commutative: eq(a,b) should always give the same as eq(b,a).

The actual comparison is:

\[ |a - b| < \max(\epsilon_r \max(|a|, |b|), \epsilon_a) \]

Note

The edge case where both values are infinite (with the same sign) returns false for equality, which could be considered reasonable because relative error is meaningless. To explicitly allow infinities to compare equal, you must test separately, e.g., a == b || soft_eq(a, b) using celeritas::EqualOr.

Constructor & Destructor Documentation

SoftEqual()

template<class RealType >

celeritas::SoftEqual< RealType >::SoftEqual	(	value_type	rel,
		value_type	abs
	)

Construct with both relative and absolute precision.

Parameters

rel	tolerance of relative error (default 1.0e-12 for doubles)
abs	threshold for absolute error when comparing small quantities (default 1.0e-14 for doubles)

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

• SoftEqual.hh