lar::util::RealComparisons< RealType > Struct Template Reference

Provides simple real number checks. More...

#include <RealComparisons.h>

Public Types
using	Value_t = RealType

Public Member Functions
constexpr	RealComparisons (Value_t threshold)
	type of values being compered More...
constexpr bool	zero (Value_t value) const
	Returns whether the value is no farther from 0 than the threshold. More...
constexpr bool	nonZero (Value_t value) const
	Returns whether the value is farther from 0 than the threshold. More...
constexpr bool	equal (Value_t a, Value_t b) const
	Returns whether a and b are no farther than the threshold. More...
constexpr bool	nonEqual (Value_t a, Value_t b) const
	Returns whether a and b are farther than the threshold. More...
constexpr bool	strictlyNegative (Value_t value) const
	Returns whether value is larger than zero beyond tolerance. More...
constexpr bool	strictlyPositive (Value_t value) const
	Returns whether value is smaller than zero beyond tolerance. More...
constexpr bool	nonNegative (Value_t value) const
	Returns whether value is larger than or equal() to zero. More...
constexpr bool	nonPositive (Value_t value) const
	Returns whether value is smaller than or equal() to zero. More...
constexpr bool	strictlySmaller (Value_t a, Value_t b) const
	Returns whether a is strictly smaller than b. More...
constexpr bool	nonSmaller (Value_t a, Value_t b) const
	Returns whether a is greater than (or equal to) b. More...
constexpr bool	strictlyGreater (Value_t a, Value_t b) const
	Returns whether a is strictly greater than b. More...
constexpr bool	nonGreater (Value_t a, Value_t b) const
	Returns whether a is smaller than (or equal to) b. More...
constexpr bool	within (Value_t value, Value_t lower, Value_t upper) const
	Returns whether value is between the bounds (included) More...
constexpr bool	withinSorted (Value_t value, Value_t lower, Value_t upper) const
	Returns whether value is between bounds (included); bounds are sorted. More...

Public Attributes
Value_t	threshold

Detailed Description

template<typename RealType>
struct lar::util::RealComparisons< RealType >

Provides simple real number checks.

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Template Parameters

RealType

type of value to operate on

This class provides some members to perform comparisons between real numbers, allowing for some tolerance for rounding errors.

The tolerance parameter is fixed. Example of usage:

lar::util::RealComparisons<float> check(1e-5);

double const sqrt2 = std::sqrt(2);

// it should print the message
if (check.equal(sqrt2, 1.4142)) {
  std::cout
    << "Square root of 2 is not even close to 1.4142." << std::endl;
}

// it should not print the message
if (check.equal(sqrt2, 1.414213)) {
  std::cout
    << "Square root of 2 is not even close to 1.414213." << std::endl;
}

// this should print the message
if (check.within(std::sqrt(2), 0., 1.41421)) {
  std::cout
    << "Square root of 2 is between 0 and 1.41421 (tops)." << std::endl;
}

// this will probably print the message
double const epsilon = 2.0 - (sqrt2 * sqrt2);
if (check.zero(epsilon)) {
  std::cout
    << "The square of the square root of 2 is roughly 2." << std::endl;
}

Definition at line 66 of file RealComparisons.h.

Member Typedef Documentation

template<typename RealType>

using lar::util::RealComparisons< RealType >::Value_t = RealType

Definition at line 67 of file RealComparisons.h.

Constructor & Destructor Documentation

template<typename RealType>

constexpr lar::util::RealComparisons< RealType >::RealComparisons ( Value_t  threshold )

inline

type of values being compered

Constructor: specify the threshold

Definition at line 70 of file RealComparisons.h.

: threshold(threshold) {}

Member Function Documentation

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::equal ( Value_t  a, Value_t  b  ) const

inline

Returns whether a and b are no farther than the threshold.

Definition at line 81 of file RealComparisons.h.

        { return zero(a - b); }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::nonEqual ( Value_t  a, Value_t  b  ) const

inline

Returns whether a and b are farther than the threshold.

Definition at line 85 of file RealComparisons.h.

        { return !equal(a, b); }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::nonGreater ( Value_t  a, Value_t  b  ) const

inline

Returns whether a is smaller than (or equal to) b.

Definition at line 117 of file RealComparisons.h.

        { return nonPositive(a - b); }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::nonNegative ( Value_t  value ) const

inline

Returns whether value is larger than or equal() to zero.

Definition at line 97 of file RealComparisons.h.

        { return value >= -threshold; }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::nonPositive ( Value_t  value ) const

inline

Returns whether value is smaller than or equal() to zero.

Definition at line 101 of file RealComparisons.h.

        { return value <= threshold; }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::nonSmaller ( Value_t  a, Value_t  b  ) const

inline

Returns whether a is greater than (or equal to) b.

Definition at line 109 of file RealComparisons.h.

        { return nonNegative(a - b); }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::nonZero ( Value_t  value ) const

inline

Returns whether the value is farther from 0 than the threshold.

Definition at line 77 of file RealComparisons.h.

        { return !zero(value); }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::strictlyGreater ( Value_t  a, Value_t  b  ) const

inline

Returns whether a is strictly greater than b.

Definition at line 113 of file RealComparisons.h.

        { return strictlyPositive(a - b); }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::strictlyNegative ( Value_t  value ) const

inline

Returns whether value is larger than zero beyond tolerance.

Definition at line 89 of file RealComparisons.h.

        { return value < -threshold; }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::strictlyPositive ( Value_t  value ) const

inline

Returns whether value is smaller than zero beyond tolerance.

Definition at line 93 of file RealComparisons.h.

        { return value > threshold; }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::strictlySmaller ( Value_t  a, Value_t  b  ) const

inline

Returns whether a is strictly smaller than b.

Definition at line 105 of file RealComparisons.h.

        { return strictlyNegative(a - b); }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::within ( Value_t  value, Value_t  lower, Value_t  upper  ) const

inline

Returns whether value is between the bounds (included)

Definition at line 121 of file RealComparisons.h.

        { return nonNegative(value - lower) && nonPositive(value - upper); }

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::withinSorted ( Value_t  value, Value_t  lower, Value_t  upper  ) const

inline

Returns whether value is between bounds (included); bounds are sorted.

Definition at line 126 of file RealComparisons.h.

        {
          return (lower < upper)
            ? within(value, lower, upper)
            : within(value, upper, lower)
            ;
        } // sortedWithin

template<typename RealType>

constexpr bool lar::util::RealComparisons< RealType >::zero ( Value_t  value ) const

inline

Returns whether the value is no farther from 0 than the threshold.

Definition at line 73 of file RealComparisons.h.

        { return std::abs(value) <= threshold; }

Member Data Documentation

template<typename RealType>

Value_t lar::util::RealComparisons< RealType >::threshold

Definition at line 134 of file RealComparisons.h.

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

• RealComparisons.h