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Re: FW: Matrix index, Please e-mail back.
From: |
Jordi Gutierrez Hermoso |
Subject: |
Re: FW: Matrix index, Please e-mail back. |
Date: |
Tue, 5 Dec 2006 17:00:55 -0600 |
Argh... No offense, and I normally try to be tolerant about top-posters
and HTML emails, but this time I honestly have a hard time understand
who said what and what's going on with this email thread. Ever heard
of trim-posting? To be fair, not many people are even aware that a
different posting style exists:
http://en.wikipedia.org/wiki/Top-posting
Anyways, after a while of reading this thread, I think I understand
what's going on. More trim-posted below:
[huge snip]
On 5-Dec-2006, Jorgen Andersson wrote:
| I want to index with [2,3,4] and then [3,4,5] ... [4,5,6] by letting
| i index the index range matrix. Can you do it with octave.
| My octave script works if in a loop. The loop is some slow
| so that is why I would like to use an index to the index ranges.
[more snipped]
I don't understand what you think the bug is, but jwe seemed
unimpressed with your bug report.
At any rate, it sounds you want to get the diagonal of a matrix plus
the super- and subdiagonal. This is easy to do:
octave:2> A = [1 2 3 4; 5 6 7 8; 9 10 11 12; 13 14 15 16]
A =
1 2 3 4
5 6 7 8
9 10 11 12
13 14 15 16
octave:3> diag(A)
ans =
1
6
11
16
octave:4> diag(A,1)
ans =
2
7
12
octave:5> diag(A,-1)
ans =
5
10
15
If I misunderstood, then please rephrase your question or reformat the
email thread. Sorry to be so pedantic about this. ;-)
HTH,
- Jordi G. H.