/**
* @overload static bool AreEqual(float first, float second, float marginOfError, int ulpTolerance)
* */
public static bool AreEqual(float first, float second, float marginOfError, int ulpTolerance)
{
// When numbers are very close to zero, this initial check of absolute values is needed. Otherwise
// we can safely use the ULP difference.
float absoluteDiff = Math.Abs(first - second);
if (absoluteDiff <= marginOfError)
{
return(true);
}
SingleInfo firstInfo = new SingleInfo(first);
SingleInfo secondInfo = new SingleInfo(second);
// Different signs mean the numbers don't match, period.
if (firstInfo.IsNegative != secondInfo.IsNegative)
{
return(false);
}
// Find the difference in ULPs (unit of least precision).
int ulpDiff = Math.Abs(firstInfo.Bits - secondInfo.Bits);
if (ulpDiff <= ulpTolerance)
{
return(true);
}
return(false);
}
/**
* @overload static int Boundary(float value, float marginOfError, int ulpTolerance, int boundaryScale)
* */
public static int Boundary(float value, float marginOfError, int ulpTolerance, int boundaryScale)
{
SingleInfo valueInfo = new SingleInfo(Math.Abs(value));
SingleInfo valueWithErrorInfo = new SingleInfo(Math.Abs(value) + marginOfError);
int ulpBoundary = ulpTolerance * boundaryScale;
int marginBoundary = (valueWithErrorInfo.Bits - valueInfo.Bits) * boundaryScale;
return(Math.Max(ulpBoundary, marginBoundary));
}
/**
* @overload static int ULPDistance(float first, float second)
* */
public static int ULPDistance(float first, float second)
{
SingleInfo firstInfo = new SingleInfo(first);
SingleInfo secondInfo = new SingleInfo(second);
if (firstInfo.IsNegative != secondInfo.IsNegative)
{
throw new ArgumentException("Numbers have mixed signs; cannot calculate the ULP distance across the 0 boundary.");
}
return(Math.Abs(firstInfo.Bits - secondInfo.Bits));
}
/**
* @overload static float ULP(float value)
* */
public static float ULP(float value)
{
if (Single.IsNaN(value))
{
return(Single.NaN);
}
else if (Single.IsPositiveInfinity(value) || Single.IsNegativeInfinity(value))
{
return(Single.PositiveInfinity);
}
else if (value == 0.0)
{
return(Single.Epsilon);
}
else if (Math.Abs(value) == Single.MaxValue)
{
return(MaxFloatULP);
}
SingleInfo info = new SingleInfo(value);
return(Math.Abs((float)(info.Bits + 1) - value));
}
public SingleInfo(float value)
{
_value = value;
_bits = SingleInfo.SingleToInt32Bits(value);
}
