Commit b4b90af4e0

Frank Denis <124872+jedisct1@users.noreply.github.com>
2021-07-08 23:19:49
Switch rand.DefaultPrng to Xoshiro256++ (#9301)
Xoroshiro128+ is the current default non-cryptographic random number generator. This algorithm was designed to generate floating-point numbers, by only using the top 53 bits. Lower bits have a significant bias, that contradicts the documented properties for `rand.DefaultPrng`. This also has implications on everything using `Random.fill()`, including the way we generate random floating-point numbers. In addition, Xoroshiro128+ has known issues. See for example: - https://lemire.me/blog/2017/08/22/cracking-random-number-generators-xoroshiro128/ - https://www.pcg-random.org/posts/xoroshiro-fails-truncated.html Xoshiro256++ addresses these issues, while remaining very fast.
master
1 parent 1f0b77b
Changed files (1)
lib
std
rand.zig
lib/std/rand.zig
@@ -23,7 +23,7 @@ const ziggurat = @import("rand/ziggurat.zig");
 const maxInt = std.math.maxInt;
 
 /// Fast unbiased random numbers.
-pub const DefaultPrng = Xoroshiro128;
+pub const DefaultPrng = Xoshiro256;
 
 /// Cryptographically secure random numbers.
 pub const DefaultCsprng = Gimli;