I have a problem where I want to generate a set of random integer values between 1 and 5 inclusive using a probability distribution.
Poisson and Inverse Gamma are two distributions that show the characteristics I am after (majority at mean, less higher numbers) that I have found.
I am looking at using Apache Commons Math but I wasn't sure how to generate the numbers I wanted using the distributions available.
From your problem description, it sounds like you actually want a sample generated from a discrete probability distribution, and you can use EnumeratedIntegerDistribution
for this purpose. Choose appropriate probabilities for each of your integers, maybe something like the following would meet your needs:
int[] numsToGenerate = new int[] { 1, 2, 3, 4, 5 };
double[] discreteProbabilities = new double[] { 0.1, 0.25, 0.3, 0.25, 0.1 };
EnumeratedIntegerDistribution distribution =
new EnumeratedIntegerDistribution(numsToGenerate, discreteProbabilities);
int numSamples = 100;
int[] samples = distribution.sample(numSamples);
Just tweak the discreteProbabilities
values to whatever you require.