From: Brian Gough <bjg@network-theory.co.uk>
To: Faheem Mitha <faheem@email.unc.edu>
Cc: <gsl-discuss@sources.redhat.com>
Subject: Re: modifying matrix allocation functions for use with R
Date: Wed, 19 Dec 2001 13:20:00 -0000 [thread overview]
Message-ID: <15300.16522.24552.163786@debian> (raw)
In-Reply-To: <Pine.LNX.4.33.0110091729260.24042-100000@Chrestomanci>
Faheem Mitha writes:
> Surely, this should be "...the input matrix A contain the matrix U"?
Thanks. Now fixed.
> Incidentally, it is a little awkward to compute the inverse of a matrix,
> since this involves calling both int gsl_linalg_LU_decomp and int
> gsl_linalg_LU_invert. Would it not be useful to have a "wrapper" function
> which uses both together?
Maybe, but in this case computing the inverse matrix is not something
I want to encourage, as it's usually better to solve Ax=b instead.
> I have one (slighly idle) question. I have noticed that macros are used
> quite liberally in the gsl source code, for example you have a macro
> called TYPE which seems to do nothing at all, there is another macro
> called PUNCTION(foo, bar) which concatenates foo and bar etc. I'm just
> wondering what purpose some of these serve, like the TYPE macro for
> example. Do they just make the code easier to write?
These macros are used to make the functions for different types,
gsl_vector_float, gsl_vector_int, etc. See the file templates_on.h
for details.
Brian
next prev parent reply other threads:[~2001-12-19 13:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-12-19 13:20 Faheem Mitha
2001-12-19 13:20 ` Brian Gough
2001-12-19 13:20 ` Faheem Mitha
2001-12-19 13:20 ` Brian Gough [this message]
2001-12-19 13:20 ` calculating matrix inverses (was Re: modifying matrix allocationfunctions for use with R) Faheem Mitha
2001-12-19 13:20 ` James Theiler
2001-12-19 13:20 ` Faheem Mitha
2001-12-19 13:20 ` modifying matrix allocation functions for use with R Timothy H. Keitt
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