# Strange behaviour of Rb-Gsl random numbers (Windows one-clic

**URL:** <https://www.ruby-forum.com/t/strange-behaviour-of-rb-gsl-random-numbers-windows-one-clic/95594>\
**Category:** Ruby\
**Created:** [June 7, 2006, 12:28am UTC](https://www.ruby-forum.com/t/strange-behaviour-of-rb-gsl-random-numbers-windows-one-clic/95594 "2006-06-07T00:28:55Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [June 7, 2006, 12:28am UTC](https://www.ruby-forum.com/t/strange-behaviour-of-rb-gsl-random-numbers-windows-one-clic/95594/1 "2006-06-07T00:28:55Z")

</div>

Dear all,

I’ve installed Rb-gsl for the Ruby-one click installer,  
and tried GSL::Rng.new.uniform to get a random number.  
This works, but always gives the same number:

require “gsl”

res=[]  
for k in 0…20  
res\<\<GSL::Rng.new.uniform  
end  
p res

> res=[0.999741748906672, 0.999741748906672, 0.999741748906672,  
> 0.999741748906672, 0.999741748906672, 0.999741748906672,  
> 0.999741748906672,  
> 0.999741748906672, 0.999741748906672, 0.999741748906672,  
> 0.999741748906672,  
> 0.999741748906672, 0.999741748906672, 0.999741748906672,  
> 0.999741748906672,  
> 0.999741748906672, 0.999741748906672, 0.999741748906672,  
> 0.999741748906672,  
> 0.999741748906672, 0.999741748906672]

Why ?

Thank you,

best regards,

Axel

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [June 7, 2006, 12:38am UTC](https://www.ruby-forum.com/t/strange-behaviour-of-rb-gsl-random-numbers-windows-one-clic/95594/2 "2006-06-07T00:38:02Z")

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On Wed, 7 Jun 2006 removed\_email\_address@domain.invalid wrote:

> res=[]  
> 0.999741748906672, 0.999741748906672]
> 
> Why ?

you have to specify what kind of random number generator you want. try  
this

irb(main):023:0\> r = GSL::Rng.alloc Rng::TAUS, 1  
=\> GSL::Rng

irb(main):024:0\> Array.new(20).map{ r.uniform }  
=\> [0.186914603225887, 0.951039797859266, 0.545435771113262,  
0.0746261349413544, 0.22921886225231, 0.522971297148615,  
0.0927675529383123,  
0.511819139821455, 0.339204750722274, 0.793815617682412,  
0.00488071935251355,  
0.342924846103415, 0.296411268645898, 0.933765491936356,  
0.208252872806042,  
0.0223858365789056, 0.256050609983504, 0.684481433359906,  
0.983118103351444,  
0.441584395710379]

[http://rb-gsl.rubyforge.org/rng.html](http://rb-gsl.rubyforge.org/rng.html)

regards.

-a

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [June 7, 2006, 12:50am UTC](https://www.ruby-forum.com/t/strange-behaviour-of-rb-gsl-random-numbers-windows-one-clic/95594/3 "2006-06-07T00:50:48Z")

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On Wed, 7 Jun 2006 removed\_email\_address@domain.invalid wrote:

> res=[]  
> 0.999741748906672, 0.999741748906672]
> 
> Why ?
> 
> Thank you,
> 
> best regards,
> 
> Axel

i confirmed it - this works on my windows box:

jib:~ \> ruby -r gsl -e’ include GSL; r = Rng.alloc Rng::TAUS, 1; p  
Array.new(20).map!{ r.uniform } ’

[0.186914603225887, 0.951039797859266, 0.545435771113262,  
0.0746261349413544,  
0.22921886225231, 0.522971297148615, 0.0927675529383123,  
0.511819139821455,  
0.339204750722274, 0.793815617682412, 0.00488071935251355,  
0.342924846103415,  
0.296411268645898, 0.933765491936356, 0.208252872806042,  
0.0223858365789056,  
0.256050609983504, 0.684481433359906, 0.983118103351444,  
0.441584395710379]

regards.

-a