From Martin Maechler <maechler@stat.math.ethz.ch>  Fri Jan 22 10:22:06 1999
From: Martin Maechler <maechler@stat.math.ethz.ch> (Martin Maechler)
Date: Fri, 22 Jan 1999 11:22:06 +0100
Subject: backsolve... --> class()es for special matrices ?
In-Reply-To: <Pine.GSO.3.96.990122100434.29339Q-101000@laplace> (message from
 Jonathan Rougier on Fri, 22 Jan 1999 10:14:49 +0000 (GMT))
Message-ID: <199901221022.LAA14764@sophie.ethz.ch>

>>>>> "JonR" == Jonathan Rougier <J.C.Rougier@durham.ac.uk> writes:

    JonR> I attach my versions of solve methods for triangular and variance
    JonR> matrices.  The triangular method is a wrapper for backsolve()
    JonR> which allows both a trans flag and a right flag (ie giving the
    JonR> four different solves that you alluded to).  The variance method
    JonR> uses a cholesky decomposition and then two triangular solves (one
    JonR> with the trans flag set), as recommended by Golub and van Loan.
    JonR> I have taken care with the returning vector/matrix, as in the
    JonR> backsolve() patch!

    JonR> I was not in on the previous Matrix class discussion.  I use them
    JonR> in Splus, but from a purely aesthetic point of view I don't like
    JonR> the idea that R would need a Matrix add-on.  I think I would
    JonR> rather see the appropriate methods built into the base.

I agree [at least as long as we only do small wrappers, etc..].
My point was that I want to use the same class() names as S+'s Matrix
library -- in those cases where do (+/-) the same.

Martin



-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !)  To: r-devel-request@stat.math.ethz.ch
_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._


backsolve... --> class()es for special matrices ?
Martin Maechler