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Re: how do I vectorize this?
From: |
Etienne Grossmann |
Subject: |
Re: how do I vectorize this? |
Date: |
Fri, 14 Apr 2006 10:48:16 -0400 |
User-agent: |
Mutt/1.4.2.1i |
Hi,
sthing like this?
octave:2> help loop_add
loop_add is the dynamically-linked function from the file
/homeætienne/progøctave/miscøctave-3Dvision/misc/loop_add.oct
-- Loadable Function: B = loop_add (A, INDICES, WHAT)
This function is equivalent to, but is quicker than :
B=A; for J=1:rows(INDICES(:)), B(INDICES(J)) += WHAT(J); end
WHAT is optional and is 1 by default.
If WHAT has less elements than INDICES, values of WHAT are
wrapped. I.e. WHAT(1 + rem(J-1,rows(WHAT(:))) is used instead of
WHAT(J).
octave:11> loop_add (zeros(1,10),(1:3).^2)
ans =
1 0 0 1 0 0 0 0 1 0
octave:12> loop_add (zeros(1,10),(1:3).^2,2*ones(1,3))
ans =
2 0 0 2 0 0 0 0 2 0
octave:13> loop_add (zeros(1,10),(1:3).^2,[2 3])
ans =
2 0 0 3 0 0 0 0 2 0
octave:14> loop_add (zeros(1,10),(1:4).^2,[2 3])
error: loop_add: Can't add to a(16) because a has only 10 elements.
If yes, it's in the attachment.
Hth,
Etienne
On Fri, Apr 14, 2006 at 12:56:43PM +0200, Miroslaw Kwasniak wrote:
# On Fri, Apr 14, 2006 at 10:52:18AM +0200, Claudio Belotti wrote:
# >
# > Hi Brendan,
# > thank you for your reply. This is not really what I need as my data are
ungridded I don't think it would be convinient to organize them in a matrix.
#
# Look in archives for an idea in thread "for i=1:bignum, x(a(i)) += y(i);
# end" from 2005.
#
# PS
#
# I think octave archives are incomplete, I'm sure that were more then two
# posts in this thread :(
#
#
#
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--
Etienne Grossmann ------ http://www.cs.uky.edu/~etienne
loop_add.cc
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