/// <summary>
///
/// </summary>
/// <param name="d"></param>
/// <returns></returns>
public static double TruncateToPowerOfTwo(double d)
{
var db = new DoubleBits(d);
db.ZeroLowerBits(52);
return(db.Double);
}
/// <summary>
///
/// </summary>
/// <param name="level"></param>
/// <param name="itemEnv"></param>
private void ComputeKey(int level, Envelope itemEnv)
{
double quadSize = DoubleBits.PowerOf2(level);
_pt.X = Math.Floor(itemEnv.MinX / quadSize) * quadSize;
_pt.Y = Math.Floor(itemEnv.MinY / quadSize) * quadSize;
_env.Init(_pt.X, _pt.X + quadSize, _pt.Y, _pt.Y + quadSize);
}
/// <summary>
///
/// </summary>
/// <param name="env"></param>
/// <returns></returns>
public static int ComputeQuadLevel(Envelope env)
{
double dx = env.Width;
double dy = env.Height;
double dMax = dx > dy ? dx : dy;
int level = DoubleBits.GetExponent(dMax) + 1;
return(level);
}
/// <summary>
/// This computes the number of common most-significant bits in the mantissa.
/// It does not count the hidden bit, which is always 1.
/// It does not determine whether the numbers have the same exponent - if they do
/// not, the value computed by this function is meaningless.
/// </summary>
/// <param name="db"></param>
/// <returns> The number of common most-significant mantissa bits.</returns>
public int NumCommonMantissaBits(DoubleBits db)
{
for (int i = 0; i < 52; i++)
{
if (GetBit(i) != db.GetBit(i))
{
return(i);
}
}
return(52);
}
/// <summary>
/// Computes whether the interval [min, max] is effectively zero width.
/// I.e. the width of the interval is so much less than the
/// location of the interval that the midpoint of the interval cannot be
/// represented precisely.
/// </summary>
public static bool IsZeroWidth(double min, double max)
{
double width = max - min;
if (width == 0.0)
{
return(true);
}
double maxAbs = Math.Max(Math.Abs(min), Math.Abs(max));
double scaledInterval = width / maxAbs;
int level = DoubleBits.GetExponent(scaledInterval);
return(level <= MinBinaryExponent);
}
/// <summary>
///
/// </summary>
/// <param name="d1"></param>
/// <param name="d2"></param>
/// <returns></returns>
public static double MaximumCommonMantissa(double d1, double d2)
{
if (d1 == 0.0 || d2 == 0.0)
{
return(0.0);
}
var db1 = new DoubleBits(d1);
var db2 = new DoubleBits(d2);
if (db1.Exponent != db2.Exponent)
{
return(0.0);
}
int maxCommon = db1.NumCommonMantissaBits(db2);
db1.ZeroLowerBits(64 - (12 + maxCommon));
return(db1.Double);
}
/// <summary>
///
/// </summary>
/// <param name="d"></param>
/// <returns></returns>
public static string ToBinaryString(double d)
{
var db = new DoubleBits(d);
return(db.ToString());
}
/// <summary>
///
/// </summary>
/// <param name="d"></param>
/// <returns></returns>
public static int GetExponent(double d)
{
var db = new DoubleBits(d);
return(db.Exponent);
}