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outer product
From: |
Fredrik Bülow |
Subject: |
outer product |
Date: |
Tue, 27 Jun 2006 11:59:38 +0200 |
Hi, on the wish list at
http://www.gnu.org/software/octave/projects.html i fund the following
request:
Given two vectors x and y of length m and n, implement a function
outer (x, y, f) that returns an m-by-n matrix with entries f (x(i),
y(j)). If f is omitted, multiplication is the default. Should probably
work for any vectors, not just if x is a column vector and y is a row
vector.
This can be done simply the one line
reshape (f (x(:)(:,ones(1,length(y))) (:), \
y(:)(:,ones(1,length(x))).'(:)),\
length(x), length(y))
plus a test to see if f is set if the special case should be dealt
with as described.
/Fredrik
- outer product,
Fredrik Bülow <=