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Re: a few questions about discrete rng
- From: James Theiler <jt at lanl dot gov>
- To: Rodney Sparapani <rsparapa at post dot its dot mcw dot edu>
- Cc: <gsl-discuss at sources dot redhat dot com>
- Date: Mon, 8 Jul 2002 10:06:08 -0600 (MDT)
- Subject: Re: a few questions about discrete rng
On Mon, 8 Jul 2002, Rodney Sparapani wrote:
] I'm working on a multinomial RNG for GSL. I was looking at the code in
] randist/discrete.c and I'm perplexed. For the number of categories, the type
] declaration is size_t. This is the type returned by the sizeof operator
] according to the ANSI C standard for the number of bytes that a type has. I
] don't think this is an appropriate definition. I believe it should be an
] unsigned int, but not this one which has a special meaning and makes the source
] hard to read. Also, the probability array is not of type gsl_vector. Is there
] some reason for this? If we all agree on these changes, then I will submit an
] updated discrete.c with my multinomial code. Thanks.
I'll let Brian (or others) comment on size_t; I've only recently been
introduced to the convention that uses size_t for certain unsigned
integers, usually array sizes. If I used it, I was copying somebody
else.
With respect to using gsl_vector versus an array, you ask: Is there
some reason for this? The reason is that when I wrote it, gsl_vector
was not well established (at least not in my usage). I don't have a
strong opinion. You might argue that gsl_vector is more appropriately
limited to linear algebra operations. In the early days of GSL, I
advocated an approach which required less dependencies on the various
types, but I've been won over to the single library approach, and in
that case the gsl_vector is a pretty useful type. So, once again, I
realize I'm not actually contributing anything to the discussion, and
am deferring to Brian on whether this is an appropriate use of
gsl_vector.
regards,
jt
---------------------------------------------
James Theiler jt@lanl.gov
MS-D436, NIS-2, LANL tel: 505/665-5682
Los Alamos, NM 87545 fax: 505/665-4414
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