/// <summary>
/// A convenience function that returns a ToleranceFunc for use in the Root Finder routines.
/// <para>If ulpsTolerance > 0, returns (x, y) => AreNearUlps(x, y, absTolerance)</para>
/// <para>Otherwise, returns (x, y) => (x == y)</para>
/// </summary>
/// <param name="ulpsTolerance"></param>
/// <returns></returns>
public static ToleranceFunc AreNearUlps(int ulpsTolerance = DefaultUlpsTolerance)
{
if (ulpsTolerance < 0)
{
throw new Exceptions.DomainException("Requires ulpsTolerance >= 0: ulpsTolerance = {0}", ulpsTolerance);
}
bool AreNearUlps(double x, double y)
{
return(Math2.AreNearUlps(x, y, ulpsTolerance));
};
bool AreEqual(double x, double y)
{
return(x == y);
};
ToleranceFunc f;
if (ulpsTolerance > 0)
{
f = AreNearUlps;
}
else
{
f = AreEqual;
}
return(f);
}
public static void AreNear(double expected, double actual, int maxUlps, Func <string> onFalureString)
{
if (!Math2.AreNearUlps(expected, actual, maxUlps))
{
throw new AssertFailedException(onFalureString());
}
}
public static void AreNear(Complex expected, Complex actual, int maxUlps, Func <string> onFalureString)
{
bool nearRe = Math2.AreNearUlps(expected.Real, actual.Real, maxUlps);
bool nearIm = Math2.AreNearUlps(expected.Imaginary, actual.Imaginary, maxUlps);
if (nearRe && nearIm)
{
return;
}
throw new AssertFailedException(onFalureString());
}
public void AreNearUlpsTest()
{
// Uses Bruce Dawson's technique
// See http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm
// This only works for IEEE
// Adapted from his tests
foreach (var item in _Cases)
{
double x = item.X;
double y = item.Y;
int maxUlps = item.Ulps;
bool result = Math2.AreNearUlps(x, y, maxUlps);
Assert.AreEqual(item.Result, result, $"Wrong comparison - Value({x}) compared to({y})");
// reverse
result = Math2.AreNearUlps(y, x, maxUlps);
Assert.AreEqual(item.Result, result, $"Wrong comparison - Value({y}) compared to({x})");
}
}