Is it good practice to use static methods for generating random numbers?

Question

I've written the following code for generating random float and double numbers.

public static class Statics
{
    private static readonly Random random = new Random();
    private static readonly object syncLock = new object();

    public static double getRandomDouble(double min, double max)
    {
        lock (syncLock)
        {
            return random.NextDouble() * (max - min) + min;
        }
    }

    public static float getRandomFloat(float min, float max)
    {
        lock (syncLock)
        {
            return (float)random.NextDouble() * (max - min) + min;
        }
    }
}

Is it OK that I'm using static class and methods for generating random numbers?

My program relies heavily on these methods so I want to make sure that the produced numbers are indeed random. These generators are being used by many objects but not simultaneously.

Yes, why not? If you just need one Random Generator per class, you can do this. — DogeAmazed, Dec 11 '16 at 15:45
As you are using locks, I assume you are using threads. If you are getting a lot of random numbers, this might introduce a bottleneck — user1781290, Dec 11 '16 at 15:49
Your question isn't really about random number generators, but about static methods, so maybe edit your question and title? And what is your definition of "ok"? — Snorex, Dec 11 '16 at 15:52

score 6 · Accepted Answer · edited May 23 '17 at 12:24

There is no reason using Random in a static context would be a problem, but, keep in mind (and it seems you did) that Random is not thread-safe.

What you chose to do is to synchronize the Threads using lock.

You could, however, create a random generator which uses ThreadStatic or ThreadLocal (Which is better for that cause so you can initialize the instances lazily with different seeds), that way you will earn the performance of not being required to lock.

Also, make sure initializing the Random with a different seed for each Thread because they might be initialized the same time as you can see on this answer:

public static class StaticRandom
{
    static int seed = Environment.TickCount;

    static readonly ThreadLocal<Random> random =
        new ThreadLocal<Random>(() => new Random(Interlocked.Increment(ref seed)));

    public static int Rand()
    {
        return random.Value.Next();
    }
}

Is it good practice to use static methods for generating random numbers?

1 Answers1