From help-request at octave dot org Sun Feb 6 11:22:45 2005 Subject: Re: subsums From: Mike Miller To: "Dmitri A. Sergatskov" cc: brumen at hispeed dot ch, help@octave.org Date: Sun, 6 Feb 2005 11:20:40 -0600 (CST) On Sun, 6 Feb 2005, Dmitri A. Sergatskov wrote: > Gorazd Brumen wrote: >> Hi, >> >> How do you form a vector of subsums of a certain vector without the for >> loop? >> Example: >> Let x = [1 2 3 4 5 6 7 8 9 10] >> I want to get a vector that would have as entries >> sum([1 2 3 4 5]) and sum ([6 7 8 9 10])? >> > > octave:1> x = [1 2 3 4 5 6 7 8 9 10] > x = > > 1 2 3 4 5 6 7 8 9 10 > > octave:2> y=reshape(x,5,2) > y = > > 1 6 > 2 7 > 3 8 > 4 9 > 5 10 > > octave:3> z=sum(y) > z = > > 15 40 Or, in general, for even N: N=10 (for example) z=sum(reshape([1:N],N/2,2)) z = 15 40 Mike ------------------------------------------------------------- Octave is freely available under the terms of the GNU GPL. Octave's home on the web: http://www.octave.org How to fund new projects: http://www.octave.org/funding.html Subscription information: http://www.octave.org/archive.html -------------------------------------------------------------