/// <summary>
/// Samples one multinomial distributed random variable.
/// </summary>
/// <param name="rnd">The random number generator to use.</param>
/// <param name="p">An array of nonnegative ratios: this array does not need to be normalized
/// as this is often impossible using floating point arithmetic.</param>
/// <param name="n">The number of trials.</param>
/// <returns>the counts for each of the different possible values.</returns>
public static int[] Sample(Random rnd, double[] p, int n)
{
if (Control.CheckDistributionParameters && !IsValidParameterSet(p, n))
{
throw new ArgumentOutOfRangeException(Resources.InvalidDistributionParameters);
}
// The cumulative density of p.
var cp = Categorical.UnnormalizedCdf(p);
// The variable that stores the counts.
var ret = new int[p.Length];
for (var i = 0; i < n; i++)
{
ret[Categorical.DoSample(rnd, cp)]++;
}
return(ret);
}