//---------------------------------------------------------------------------
/*
fuzzy_equal_to, fuzzy equal_to predicate
Copyright (C) 2011-2015 Richel Bilderbeek
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppFuzzy_equal_to.htm
//---------------------------------------------------------------------------
#ifndef RIBI_FUZZY_EQUAL_TO_H
#define RIBI_FUZZY_EQUAL_TO_H
#include <cassert>
#include <cmath>
#include <functional>
#include <limits>
#include <string>
#include <vector>
namespace ribi {
///fuzzy_equal_to is a predicate to test two doubles for equality
///with a certain tolerance. A tolerance of 0.0 denotes that
///an exact match is requested. Note that the value of 0.0 cannot
///be compared fuzzily.
///From http://www.richelbilderbeek.nl/CppFuzzy_equal_to.htm
struct fuzzy_equal_to
{
explicit fuzzy_equal_to(const double tolerance = std::numeric_limits<double>::epsilon())
: m_tolerance(tolerance)
{
assert(tolerance >= 0.0);
}
bool operator()(const double lhs, const double rhs) const
{
assert(lhs != 0.0);
return rhs > (1.0 - m_tolerance) * lhs
&& rhs < (1.0 + m_tolerance) * lhs;
}
const double m_tolerance;
static std::string GetVersion()
{
return "1.4";
}
static std::vector<std::string> GetVersionHistory()
{
return {
"2011-02-24: version 1.0: initial version",
"2012-11-14: version 1.1: set default tolerance to std::numeric_limits<double>::epsilon()",
"2012-11-18: version 1.2: added #pragma's to file to suppress -Weffc++ warnings",
"2012-11-18: version 1.3: added #include <limits>",
"2014-12-27: version 1.4: do not inherit from deprecated std::binary_function"
};
}
};
///fuzzy_equal_to_abs is a predicate to test two doubles for equality
///by allowing a certain absolute difference between the two values
///A tolerance of 0.0 denotes that an exact match is requested.
///From http://www.richelbilderbeek.nl/CppFuzzy_equal_to.htm
struct fuzzy_equal_to_abs
{
explicit fuzzy_equal_to_abs(const double tolerance = std::numeric_limits<double>::epsilon())
: m_tolerance(tolerance)
{
assert(tolerance >= 0.0);
}
bool operator()(const double lhs, const double rhs) const noexcept
{
return std::abs(lhs-rhs) < m_tolerance;
}
const double m_tolerance;
static std::string GetVersion() noexcept
{
return "1.0";
}
static std::vector<std::string> GetVersionHistory() noexcept
{
return {
"2013-11-05: version 1.0: initial version from fuzzy_equal_to"
};
}
};
} //~namespace ribi
#endif // RIBI_FUZZY_EQUAL_TO_H
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