Here is a quick solution to the eigenvalue problem. Should be refined and
extended to calculate eigenvectors.
{0~⍨∈⍵×∘.=⍨⍳≢⍵}({r+.×⍉qt⊣(qt r)←⌹[⎕CT]⍵ ;qt;r}⍣{(|⍺)≡|⍵}) 3 3 ⍴ ⍳9
16.11684397 ¯1.11684397 ¯3.625973215E¯16
As a quick note, my ⎕CT was 1E¯13, however it doesn't seem to zero out the
¯3.625973215E¯16. I suspect this is due to it being a negative number. Its
not that big of a hurdle, it can be easily worked around with an extra
function. Worlframalpha for example rounds it to 0 in their solution.
Many thanks,
- Rowan
On Mon, Apr 13, 2020 at 5:30 PM Peter Teeson <peter.tee...@me.com> wrote:
> The paper you referred to was a huge epiphany for me.
> Having previously worked in the business world using COBOL and FORTRAN
> the beauty and elegance of APL blew me away. It still does.
>
> At IPSA we used to model proposed changes (mostly algorithms) to the
> interpreter in APL first.
> And then wrote the Assembly code to implement.
>
> On Apr 13, 2020, at 11:48 AM, Dr. Jürgen Sauermann <mail@xn--
> jrgen-sauermann-zvb.de> wrote:
>
> That was my point. If we could establish APL as a language for describing
> algorithms. I was thinking
> along the lines of Iverson's "Notation as a tool of thought" which is also
> free now:
>
> https://dl.acm.org/doi/10.1145/358896.358899
>
>
>
