/// <summary>
/// Samples an index from <paramref name="distribution"/>.
/// </summary>
/// <param name="distribution">A collection of values which sum to 1</param>
/// <returns>The sampled index</returns>
public static int Sample(this IEnumerable <float> distribution)
{
float sample = ThreadsafeRandom.NextFloat() * distribution.Sum();
Queue <float> values = new Queue <float>(distribution);
int index = 0;
while (sample > 0 && values.Count > 0)
{
sample -= values.Dequeue();
index++;
}
return(index - 1);
}
/// <summary>
/// Samples an index from <paramref name="list"/> using <paramref name="selector"/> to transform <typeparamref name="T"/> to a float.
/// </summary>
/// <typeparam name="T">Type of the list</typeparam>
/// <param name="list">The list to sample</param>
/// <param name="selector">Function used to create a normalized list</param>
/// <returns>The sampled index</returns>
public static int Sample <T>(this IEnumerable <T> list, Func <T, float> selector)
{
float sample = ThreadsafeRandom.NextFloat() * list.Sum(selector);
Queue <float> values = new Queue <float>(from item in list
select selector(item));
int index = 0;
while (sample > 0 && values.Count > 0)
{
sample -= values.Dequeue();
index++;
}
return(index - 1);
}