Random Number Update

Tue Jan 24 16:05:02 UTC 2017

This is not a core library or blessed libraries issue. This is a
communication issue. You don't want to be involved in the v2 work.  That's
fine.

On Tue, Jan 24, 2017 at 10:55 AM <dominic at steinitz.org> wrote:

> Carter,
>
> I obviously didn’t explain myself very well. We can decouple removing the
> “bad” RNG from the replacement of it with a “good” RNG. As I thought I
> said, any new RNG should have the same status as every other RNG and then
> people can choose; there is no “blessed” RNG. It seems simple (to me at any
> rate) to decouple these.
>
> More power to your elbow on creating an RNG but I don’t think there should
> be anything “official” about it. I’ll say it again: I don’t think there
> should be a random v2 but a random-foobar where foobar is your algorithm.
>
> What do you see sub-optimal about deprecating something that is clearly
> broken?
>
> I believe I have done my bit for the Haskell Community in trying to
> resolve what is a tedious situation. I suggest we await the view of the
> Core Libraries Committee assuming they still see this as part of their
> scope and take it from there.
>
> Dominic.
>
> On 24 Jan 2017, at 15:33, Carter Schonwald <carter.schonwald at gmail.com>
> wrote:
>
> Dominic, if you want to remove yourself from maintainer hood that's cool.
>
> I'm keen on finishing up my random v2 release which is a much improved
> breaking Change.
>
> I spent part of my holiday this year working on it.
>
> Dominic: I'm confused and surprised by your email after we had a one hour
> phone chat about this topic last week.
>
> I'm disappointed you are still raising concerns I addressed and explained
> to you last week.
>
> Random v2 is in flight. You are welcome to stop being involved.
>
> On Tue, Jan 24, 2017 at 10:19 AM Adam Bergmark <adam at bergmark.nl> wrote:
>
> On Tue, 24 Jan 2017 at 14:36 Dominic Steinitz <dominic at steinitz.org>
> wrote:
>
> I wanted to give an update on the status of random numbers in Haskell.
>
>
>
>
>
>  1. It is well known that the random number generator package
>
>
>     https://hackage.haskell.org/package/random gives unexpected
>
>
>     results.
>
>
>  2. Most people do *not* use it. I believe
>
>
>     https://hackage.haskell.org/package/mwc-random is a popular choice
>
>
>     but developers are free to use e.g. Mersenne Twister, PCG
>
>
>     (Permuted Congruential Generator), TF (ThreeFish) and many others.
>
>
>  3. Approximately 2 years, I made a proposal to replace the algorithm
>
>
>     within random (https://hackage.haskell.org/package/random) with
>
>
>     that used by tf-random
>
>
>     (https://hackage.haskell.org/package/tf-random) which is used by
>
>
>     QuickCheck. In summary, the response to this was that someone
>
>
>     should do more research with the result that nothing happened.
>
>
>  4. In the meantime, random
>
>
>     (https://hackage.haskell.org/package/random) is *no longer* a core
>
>
>     library. It's just a library with the same status as
>
>
>     e.g. mwc-random. However, it has one difference: it uses the name
>
>
>     for its module: "System.Random". Other RNGs use
>
>
>     "System.Random.MWC", "System.Random.PCG", "System.Random.Mersenne"
>
>
>     etc.
>
>
>
>
>
> As a maintainer of random
>
>
> (https://hackage.haskell.org/package/random), my proposal now is to
>
>
> deprecate all of it.
>
>
>
>
>
> I am not clear what the policy is on namespace usage. Could every RNG
>
>
> use the module name "System.Random"? Or is this somehow reserved? If
>
>
> the latter then I propose that *nothing* uses this name and that all
>
>
> RNGs should add a suffix indicating which algorithm they use.
>
>
> They *could* use the same namespace but I don't recommend it. If someone
> depends on two of these packages they would have to use PackageImports.
> Tools such as doctest break if a package db has module conflicts, even if
> only one of the packages is listed as a dependency.
>
> Cheers,
> Adam
>
>
>
>
>
>
> I note that the Haskell Platform contains tf-random so users of this
>
>
> will still be able to generate (better) random numbers.
>
>
>
>
>
> If someone comes along in the future, as I hope they do, and
>
>
> implements e.g. Guy Steele's splitmix algorithm then this can occupy
>
>
> the name "System.Random.Splitmix" and have the package name
>
>
> "random-splitmix".
>
>
>
>
>
> The advantages of doing this are:
>
>
>
>
>
>  1. Neophyte (and experienced) Haskellers do not accidentally use an
>
>
>     RNG which gives unexpected results.
>
>
>  2. No-one will any longer be able to write blogs or papers about this
>
>
>     embarrassing aspect of Haskell.
>
>
>
>
>
> I believe the co-maintainer of random
>
>
> (https://hackage.haskell.org/package/random), Carter Schonwald, has a
>
>
> different view on this matter but it is best he speaks for himself
>
>
> rather than me imperfectly trying to reflect his thinking.
>
>
>
>
>
> Dominic Steinitz
>
>
> dominic at steinitz.org
>
>
> http://idontgetoutmuch.wordpress.com
>
>
>
>
>
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>
>
>
> Dominic Steinitz
> dominic at steinitz.org
> http://idontgetoutmuch.wordpress.com
>
>
>
>
>
>
>
>
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