backsolve... --> class()es for special matrices ?
Martin Maechler
Martin Maechler <maechler@stat.math.ethz.ch>
Fri, 22 Jan 1999 11:22:06 +0100
>>>>> "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
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