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CoinFloatEqual.hpp File Reference

Function objects for testing equality of real numbers. More...

#include <algorithm>
#include <cmath>
#include "CoinFinite.hpp"
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class  CoinAbsFltEq
 Equality to an absolute tolerance. More...
class  CoinRelFltEq
 Equality to a scaled tolerance. More...

Detailed Description

Function objects for testing equality of real numbers.

Two objects are provided; one tests for equality to an absolute tolerance, one to a scaled tolerance. The tests will handle IEEE floating point, but note that infinity == infinity. Mathematicians are rolling in their graves, but this matches the behaviour for the common practice of using DBL_MAX (numeric_limits<double>::max(), or similar large finite number) as infinity.

Example usage:

  double d1 = 3.14159 ;
  double d2 = d1 ;
  double d3 = d1+.0001 ;

  CoinAbsFltEq eq1 ;
  CoinAbsFltEq eq2(.001) ;

  assert(  eq1(d1,d2) ) ;
  assert( !eq1(d1,d3) ) ;
  assert(  eq2(d1,d3) ) ;

CoinRelFltEq follows the same pattern.

Definition in file CoinFloatEqual.hpp.