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));
}