[Mono-osx] bug in Random

[Geoff Norton]

Rodrigo is on the Mono team and has already answered you.

On Sun, 2009-01-25 at 14:24 -0500, Duane Wandless wrote:
> Hello Mono-team... Can you please provide an answer?  Was the
> intention to use a different algorithm for the Random class, or was
> that a mistake?  Honestly I cannot see a technical reason to use a
> different one.
> 
> 
> Thanks.
> 
> On Mon, Jan 19, 2009 at 5:43 PM, Rodrigo Kumpera <kumpera at gmail.com>
> wrote:
>         Your application depends on an implementation detail of the MS
>         runtime.
>         There is no guarantee either that they won't change the Random
>         algorithm.
>         
>         This is unfortunate to your application but the solution is
>         pretty simple, copy mono's
>         implementation to your project and rely on it instead of an
>         external prng.
>         
>         
>         
>         
>         On Mon, Jan 19, 2009 at 8:38 PM, MacUser
>         <atlas at spiralgraphics.biz> wrote:
>                 
>                 This is also a point of concern for me.  My code ,
>                 written on Microsoft .NET,
>                 relied on the fact that using the same seed will
>                 always produce the same
>                 series of numbers.  To port to Mono, not only would I
>                 need Mono's Random()
>                 to be consistant across all Mono platforms, but also
>                 consistant to the
>                 results that Microsoft's Random() produces.
>                 
>                 By the way, I work in the algorithmic graphics
>                 generation area, where an
>                 image produced with the same input values must always
>                 look the same
>                 regardless of the platform the app is running on.
>                  This is why reliable
>                 seeding is so important.
>                 
>                 
>                 
>                 
>                 Rodrigo Kumpera wrote:
>                 >
>                 > It doesn't state the the algorithm has to be the
>                 same, just that it must
>                 > be
>                 > reproducible given the same seed.
>                 >
>                 > On Mon, Jan 19, 2009 at 3:27 PM, Duane Wandless
>                 <duane at wandless.net>
>                 > wrote:
>                 >
>                 >> That is a valid question.  From MSDN, the Random
>                 class is a Pseudo-random
>                 >> number generator:
>                 >> The random number generation starts from a seed
>                 value. If the same seed
>                 >> is
>                 >> used repeatedly, the same series of numbers is
>                 generated.
>                 >>
>                 >>
>                 http://msdn.microsoft.com/en-us/library/system.random.aspx
>                 >>
>                 >> The value in this is that given a seed will produce
>                 the same sequence of
>                 >> random numbers.  So if the client and server both
>                 know the seed then
>                 >> the algorithm will work correctly on both
>                 platforms.
>                 >>
>                 >>
>                 >> On Mon, Jan 19, 2009 at 12:09 PM, Matt Emson
>                 >> <memsom at interalpha.co.uk>wrote:
>                 >>
>                 >>> Duane Wandless wrote:
>                 >>>
>                 >>>> Maybe I incorrectly assume that the pseudo-random
>                 number should be the
>                 >>>> same on both platforms... but I believe that it
>                 should be a predictable
>                 >>>> sequence given the same seed.
>                 >>>>
>                 >>> Maybe this is a silly question, but why would you
>                 want your *random*
>                 >>> number to be the same on both platforms, more so
>                 "a predictable
>                 >>> sequence"?
>                 >>> Sure I'm missing something obvious, but... ?!
>                 >>>
>                 >>
>                 >>
>                 >> _______________________________________________
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>                 >>
>                 >>
>                 >
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>                 http://www.nabble.com/bug-in-Random-tp21544091p21553211.html
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