Yes, when I type the name of a verb which I have defined myself, I get the code:
etc
[: T [ {. [: T ]
but when I type the name of a verb which the J-implementors have defined I get
no explanation
%.
%.
It might be nice to see the definition in terms of simpler concepts.
Venlig hilsen, Bo.
--- Den man 24/8/09 skrev Rob Hodgkinson <[email protected]>:
> Fra: Rob Hodgkinson <[email protected]>
> Emne: Re: [Jprogramming] matrix inversion operator
> Til: "Programming forum" <[email protected]>
> Dato: mandag 24. august 2009 04.21
> Gene, you may recall that back in the
> early 1980's you sent me an APL
> model for Quad-Divide, which used Househoulder Transforms
> for QR
> Decomposition to produce an upper triangular matrix as you
> described.
> A key aspect of this algorithm is that it was stable for
> non-
> rectangular matrices also (Least Squares).
>
> I may still have the model at home, but I would think that
> Roger is
> the best one to answer this question for %. as he may have
> implemented
> a different model anyway.
>
> Regards, Rob Hodgkinson
>
> On 23/08/2009, at 3:18 PM, Eugene McDonnell wrote:
>
> >
> > On Jul 6, 2007, at 12:48 AM, Damien wrote:
> >
> >> Hello,
> >>
> >> I was wondering what kind of algorithm is used
> within the %.
> >> operator,
> >> because it is very powerful !! Does someone have
> any idea ?
> >> Besides, what is the best algorithm to invert
> matrix for you ? I
> >> mean if you
> >> had to implement only one algorithm for all the
> types of matrices,
> >> which one
> >> would you choose ?
> >>
> >> Thanks.
> >> Damien.
> >
> > My dim recollection is that I triangularized Matrix M,
> giving Matrix
> > T, and then the inverse is easy to compute. From that
> I went backwards
> > and got the inverse.
> >
> > I've just finished looking in my files on Matrix
> problems, but was
> > unable to find anything; very vexing.
> >
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