Saagar Jha > On May 22, 2017, at 08:44, Edward Connell via swift-users > <swift-users@swift.org> wrote: > > Any ideas when Foundation on Linux will support arc4random_uniform? This is > kind of an important function. > There doesn't seem to be any decent substitute without requiring the > installation of libbsd-dev, which turns out to be messy. Currently I am doing > this, but glibc random with mod does not produce good quality numbers, due to > modulo bias.
Modulo bias is easy to deal with, though, if you force random to produce a range that is a multiple of the range that you’re trying to produce: guard range > 0 else { return 0 } var random: Int repeat { random = Int(random()) } while(random > LONG_MAX / range * range) return random % range > > Has anyone come up with a better solution to get a true uniform distribution > that isn't super messy? > > import Foundation > > #if os(Linux) > import Glibc > #endif > > > public func random_uniform(range: Int) -> Int { > guard range > 0 else { return 0 } > #if os(Linux) > return Int(random()) % range > #else > return Int(arc4random_uniform(UInt32(range))) > #endif > } > > > Thanks, Ed > _______________________________________________ > swift-users mailing list > swift-users@swift.org > https://lists.swift.org/mailman/listinfo/swift-users
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