From murdoch at stats.uwo.ca  Tue Aug  5 15:10:23 2008
From: murdoch at stats.uwo.ca (Duncan Murdoch)
Date: Tue, 05 Aug 2008 09:10:23 -0400
Subject: [Rd] Random number generation
In-Reply-To: <b2d9df730808050547k1969d26i6ab732b914aa5c7a@mail.gmail.com>
References: <b2d9df730808050547k1969d26i6ab732b914aa5c7a@mail.gmail.com>
Message-ID: <4898513F.7040401@stats.uwo.ca>

Please don't cross-post.  This reply is going to R-devel only.

On 8/5/2008 8:47 AM, subramanian R wrote:
> Hi All,
>            I have a few queries regarding Random Number generation in R.
>            according to the help(Random.User) i defined my own functions for

That's help("Random.user")...

> user_unif_rand and user_norm_rand (uniform and normal distribution)
> 
>            But what i figured out was even when i call rexp,rpois,rgeom and
> other distributions they were routed via user_unif_rand.
> 1.  Does this mean that for all types of distribution it generates an
> Uniform distribution and transforms to the requested type?
> 
> Also   surprisingly even rnorm which i hoped to route via user_norm_rand
> was calling user_unif_rand...
> 
> 
>> rnorm(1)
> inside user_unif_rand//printf and
> inside user_unif_rand
> [1] 0.5973648
> 
> 
> Please help me out understanding this...

I think you didn't do things properly, but you didn't show us what you 
did.  When I run the sample code in help("Random.user"), adding an 
Rprintf() call to the user_norm_rand function, I see it being called.

Duncan Murdoch

> 
> 2. Our goal is to link with an vectorized Random number generator library
> for our multi-core architecture.
>     So is it enough if we define user_unif_rand function alone and will it
> take care of all distributions?
> 
> 
> Thanks in Anticipation,
> R. Subramanian
> 
> 	[[alternative HTML version deleted]]
> 
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[Rd] Random number generation
Duncan Murdoch