Note
Segment has paused maintenance on this project, but may return it to an active status in the future. Issues and pull requests from external contributors are not being considered, although internal contributions may appear from time to time. The project remains available under its open source license for anyone to use.
This package provides the implementation of a pseudo-random number source which
can be used with the standard rand.Rand
type, and supports re-seeding with no
overhead.
Note that the pseudo-random number source in this package is not safe to use for security-sensitive work.
Deterministic random number generation is a powerful tool, we use it to build systems that have testable random behaviors. While the variety of outputs they produce can be seen as randomly distributed, a given set of inputs will always produce the same outputs.
The default pseudo-random number source in the math/rand
package supports
building such systems because the sequence of numbers it generates is determined
by the value it was seeded with. However, seeding the source is an extremely
expensive operation, taking many microseconds of compute time, which doesn't
make it a good fit when the program needs to re-seed the PRNG based on inputs it
receives thousands of times per second, very quickly most of the CPU time is
spent re-seeding the PRNG.
This package provides an alternative pseudo-random number source which may not provide a distribution that is as uniform as the one in the standard library, but works well in practice, and supports re-seeding with zero overhead on CPU time.
package main
import (
"fmt"
"math/rand"
"github.com/segmentio/fastrand"
)
func main() {
s := fastrand.NewSource(0)
r := rand.New(s)
fmt.Println(r.Int())
}