/// <summary>
/// Return E raised to specified power.
/// 2x times faster than System.Math.Exp, but gives 1% error.
/// </summary>
/// <param name="power">Target power.</param>
public static float Exp(float power)
{
var c = new DoubleInt64();
c.Int64 = (long)(1512775 * power + 1072632447) << 32;
return((float)c.Double);
}
public static int Compare(double x, double y)
{
// Very important that cmp(x, y) == cmp(y, x)
if (Double.IsNaN(x) || Double.IsNaN(y))
{
return(1);
}
if (Double.IsInfinity(x) || Double.IsInfinity(y))
{
return(1);
}
var ix = DoubleInt64.Reinterpret(x);
var iy = DoubleInt64.Reinterpret(y);
var diff = Math.Abs(ix - iy);
if (diff < MaxUnitsInTheLastPlace)
{
return(0);
}
if (ix < iy)
{
return(-1);
}
else
{
return(1);
}
}
/// <summary>
/// Return data raised to specified power.
/// 4x times faster than System.Math.Pow, 6x times faster than System.Math.Pow, but gives 3% error.
/// </summary>
/// <param name="data">Data to raise.</param>
/// <param name="power">Target power.</param>
public static float PowInaccurate(float data, float power)
{
var c = new DoubleInt64();
c.Double = data;
c.Int64 = (long)(power * ((c.Int64 >> 32) - 1072632447) + 1072632447) << 32;
return((float)c.Double);
}
