C#•2mo ago

✅ Faster & thread safe random number generator?

Is there a good library for getting pseudo random numbers, faster than System.Random? I've done some looking but had a hard time coming up with much.

37 Replies

Angius•2mo ago

Do you find the speed of System.Random a bottleneck?

MechWarrior99•2mo ago

Yeah, not a massive one, but definitely is one.

Angius•2mo ago

Are you using multiple instances of Random, or Random.Shared? Or some singleton you yourself made

MechWarrior99•2mo ago

I have a large process which I create a new instance of Random for each time, since the process runs in a Task in a separate thread.

Angius•2mo ago

Random.Shared is thread-safe, IIRC

ParaLogia•2mo ago

yep https://learn.microsoft.com/en-us/dotnet/api/system.random.shared

Random.Shared Property (System)

Provides a thread-safe Random instance that may be used concurrently from any thread.

MODiX•2mo ago

Angius

REPL Result: Success

using System;
using System.Threading.Tasks;

Parallel.For(0, 10, x =>
{
    var value = Random.Shared.Next(); 
    Console.WriteLine(value);
});

using System;
using System.Threading.Tasks;

Parallel.For(0, 10, x =>
{
    var value = Random.Shared.Next(); 
    Console.WriteLine(value);
});

Console Output

1562793860548352853
252507751
1548914677
1900456204
1478899365
11502557
1227585618
1038092387

1986991436

1562793860548352853
252507751
1548914677
1900456204
1478899365
11502557
1227585618
1038092387

1986991436

Compile: 356.154ms | Execution: 96.933ms | React with ❌ to remove this embed.

Angius•2mo ago

Well this got one empty line lmao Could just be Modix though

MechWarrior99•2mo ago

Ah good to know, but I actually reset the seed each time, which is why I create a new instance each time.

Angius•2mo ago

You need deterministic random?

MechWarrior99•2mo ago

Yeah

Angius•2mo ago

Then I don't think you'll get much faster than System.Random Though you can always look for some nugers Maybe there's something that provides slightly worse randomness but is more performant I only know a less-performant way, RandomNumberGenerator, but this one's cryptographically secure

MechWarrior99•2mo ago

Yeah I don't really mind if it is a bit worse randomness (I think at least haha)

ParaLogia•2mo ago

https://xkcd.com/221/ ?

xkcd: Random Number

RFC 1149.5 specifies 4 as the standard IEEE-vetted random number.

MechWarrior99•2mo ago

I remember seeing something about using xor-shift to get random numbers, but couldn't find a lot on it. 🤔

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✅ Faster & thread safe random number generator?