This crate implements the xoshiro family of pseudorandom number generators designed by David Blackman and Sebastiano Vigna. They feature high perfomance and a small state and superseed the previous xorshift-based generators. However, they are no cryptographically secure and their output can be predicted by observing a few samples.

The following generators are implemented:

64-bit generators

• Xoshiro256StarStar: Recommended for all purposes. Excellent speed and a state space (256 bits) large enough for any parallel application.
• Xoshiro256Plus: Recommended for generating 64-bit floating-point numbers. About 15% faster than Xoshiro256StarStar, but has a low linear complexity in the lowest bits (which are discarded when generating floats), making it fail linearity tests. This is unlikely to have any impact in practise.
• Xoroshiro128StarStar: An alternative to Xoshiro256StarStar, having the same speed but using half the state. Only suited for low-scale parallel applications.
• Xoroshiro128Plus: An alternative to Xoshiro256Plus, having the same speed but using half the state. Only suited for low-scale parallel applications. Has a low linear complexity in the lowest bits (which are discarded when generating floats), making it fail linearity tests. This is unlikely to have any impact in practise.
• Xoshiro512StarStar: An alternative to Xoshiro256StarStar with more state and the same speed.
• Xoshiro512Plus: An alternative to Xoshiro512Plus with more state and the same speed. Has a low linear complexity in the lowest bits (which are discarded when generating floats), making it fail linearity tests. This is unlikely to have any impact in practise.
• SplitMix64: Recommended for initializing generators of the xoshiro familiy from a 64-bit seed. Used for implementing seed_from_u64.

32-bit generators

• Xoshiro128StarStar: Recommended for all purposes. Excellent speed.
• Xoshiro128Plus: Recommended for generating 32-bit floating-point numbers. Faster than Xoshiro128StarStar, but has a low linear complexity in the lowest bits (which are discarded when generating floats), making it fail linearity tests. This is unlikely to have any impact in practise.
• Xoroshiro64StarStar: An alternative to Xoshiro128StarStar, having the same speed but using half the state.
• Xoroshiro64Star: An alternative to Xoshiro128Plus, having the same speed but using half the state. Has a low linear complexity in the lowest bits (which are discarded when generating floats), making it fail linearity tests. This is unlikely to have any impact in practise.