Hi,
Some example of getting the main diagonal of square matrices:
]A=:2 2$1 2 3 4
1 2
3 4
(<0 1)|:A NB. The main diagonal of a square matrix A
1 4
]B=:3 3$1 2 3 4 5 6
1 2 3
4 5 6
1 2 3
(<0 1)|:B NB. The main diagonal of a square matrix B
1 5 3
]N=:4 4$i. 16
0 1 2 3
4 5 6 7
8 9 10 11
12 13 14 15
(<0 1)|:N NB. The main diagonal of a square matrix N
0 5 10 15
Regards,
Erik
----- Eredeti levél (Original Message) -----
Feladó: Alex Giannakopoulos <aeg...@blueyonder.co.uk>
Dátum: Péntek, Január 6, 2012 9:48 du
Tárgy: [Jprogramming] Getting the diagonal of a square matrix
Címzett: Programming forum <programming@jsoftware.com>
> Hi
>
> Is there a better (more efficient or whatever) way of getting
> the diagonal
> of a matrix than the simple multiplication I use below?
>
> Say,
>
> randmat=. [: ? 0 $~,~
> idmat =. [:=i.
> randiag =. randmat * idmat
>
> Many Thanks
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