public static uint NextInRange(this IRandGen gen, uint max)
{
// returns a random int between 0 and max, inclusive
if (max == uint.MaxValue) // get rid of a boundary condition
{
return(gen.NextUint());
}
// How many values at the high end of the range need to be thrown away
uint deadZone = uint.MaxValue % (max + 1) + 1;
if (deadZone == max + 1)
{
// uint.range is evenly divisible by max+1
return(gen.NextUint() % (max + 1));
}
uint maxAccept = uint.MaxValue - deadZone;
// maxaccept is now one less than a multiple of max+1
// thus, if n is a random number in [0, maxAccept],
// (n%(max+1)) is a uniform random number in [0,max]
uint rn;
do
{
rn = gen.NextUint();
} while (rn > maxAccept);
return(rn % (max + 1));
}
public static float NextFloat(this IRandGen gen)
{
// Uniformly distributed float between 0 and 1.
UInt32 val = gen.NextUint() >> 8; // 23 bits of mantissa, not including possible leading 1. This is definitely representable in a float.
return((float)val / (1 << 23));
}
public static byte[] NextBuffer(this IRandGen gen, byte[] buf)
{
for (int i = 0; i < buf.Length; i++)
{
buf[i] = gen.Next();
}
return(buf);
}
public static double NextDouble(this IRandGen gen)
{
// Uniformly distributed double between 0 and 1.
double val = (double)gen.NextUint64();
val = val / (1 << 30);
val = val / (1 << 30);
return(val / (1 << 4)); // Two separate steps to stay within range.
}
public static UInt64 NextUint64(this IRandGen gen)
{
UInt64 ret = 0;
for (int i = 0; i < 8; i++)
{
ret = ret << 8 | gen.Next();
}
return(ret);
}
public static uint NextUint(this IRandGen gen)
{
uint ret = 0;
for (int i = 0; i < 4; i++)
{
ret = ret << 8 | gen.Next();
}
return(ret);
}
public static int NextInt(this IRandGen gen)
{
// Read a big-endian integer from the generator
int ret = 0;
for (int i = 0; i < 4; i++)
{
ret = ret << 8 | gen.Next();
}
return(ret);
}
public RC4(IRandGen cloneFrom)
{
Init(cloneFrom.NextBuffer(256));
}
public static Geom.Point3d NextPoint3d(this IRandGen gen)
{
// Random point in the unit cube at the origin. ( [0,1), [0,1), [0,1) )
return(new Geom.Point3d(gen.NextDouble(), gen.NextDouble(), gen.NextDouble()));
}
public static byte[] NextBuffer(this IRandGen gen, int count)
{
byte[] buf = new byte[count];
return(gen.NextBuffer(buf));
}
public ParticleDeposition(World world, IRandGen rand, Layer <double> layer = null)
{
this.rand = rand;
this.world = world;
this.layer = layer ?? World.Height;
}
public SqueezeSphere(World w, IRandGen rand, Layer <double> layer = null)
{
this.world = w;
this.rand = rand;
this.layer = layer ?? World.Height;
}
