From: Cameron McBride <cameron.mcbride@...>
Date: 2009-05-09T05:25:33+09:00
Subject: Re: using the GSL library

On Fri, May 8, 2009 at 09:39, Jason Lillywhite
<jason.lillywhite@gmail.com> wrote:
>> be careful here.  What you just did was load the std library 'matrix'
>> library, which also defined a Vector constructor - but no method
>> called 'mean' This is very different than GSL.

> It seems a little odd that we have two kinds of vectors but they are
> both a 'vector'


not really.  "vector" in this case is just a name corresponding to a
variable (objects of a class in two independent and non-compatible
libraries).  Both libraries provide an object meant to represent a
mathematical "vector", so their names make sense in both cases. Both
are "add ons" to the language itself, which is why I cautioned you on
their use.  Be careful when one loads external libraries, there is no
guarantee that different libraries will co-exist peacefully.

The latter point is why I mentioned GSL::Vector being "a good thing"
than "include GSL; Vector".  GSL is now wrapped in a "namespace"
(module in rubyspeak) so it doesn't cause confusion with the default
namespace.

It's a subtle point when getting started, but a critical piece to keep in mind.

Cameron