From octave-maintainers-request at bevo dot che dot wisc dot edu Fri Jan 23 23:08:37 2004
Subject: Re: randn benchmarks
From: Dirk Eddelbuettel <edd at debian dot org>
To: "Dmitri A. Sergatskov" <dmitri at unm dot edu>
Cc: Paul Kienzle <pkienzle at users dot sourceforge dot net>,    David Bateman <David.Bateman@motorola.com>,    octave-maintainers@bevo.che.wisc.edu
Date: Fri, 23 Jan 2004 23:07:29 -0600


Dmitri,

On Fri, Jan 23, 2004 at 03:33:29PM -0700, Dmitri A. Sergatskov wrote:
> Dirk and Paul,
> 
> While we at it. Could someone explain it to me why Dirk's randmt is few 
> times
> faster than the randn from octave-forge?

Not entirely sure, but if I recall, I wrapped Octave's C++ somewhat directly
into Shawn Cokus' C implementation, whereas Paul, thorough as he is, had
that wrapped into another C++ layer (written by someone else). That may
contribute to it.  But I may well be of base here...

Dirk



> 
> 
> octave:2> tic ; randmt(1000); toc
> ans = 0.055763
> octave:3> tic ; randmt(3000); toc
> ans = 0.77237
> octave:4> tic ; randmt(10000); toc
> ans = 26.469
> octave:5> tic ; randn(1000); toc
> ans = 0.31140
> octave:6> tic ; randn(3000); toc
> ans = 2.7659
> octave:7> tic ; randn(10000); toc
> ans = 30.786
> ((( It does seem that times converge for very large arrays...)))
> octave:8> which randn
> randn is the dynamically-linked function from the file
> /usr/local/libexec/octave/2.1.50/site/oct/i686-pc-linux-gnu/octave-forge/randn.oct
> 
> 
> Sincerely,
> 
> Dmitri.
> 

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