
From:  Quentin Spencer 
Subject:  Re: Easy about Matrices 
Date:  Mon, 18 Apr 2005 13:20:06 0500 
Useragent:  Mozilla Thunderbird 1.0.21.3.2 (X11/20050324) 
Frank Palazzolo wrote:
This syntax works as well: x = randn(1,1000); x_positive = (x>=0); x_negative = (x<0); I'm not sure if it's any more efficient, but it seems it would be, since it never needs to build an explicit index vector. Frank
This is definitely faster, but it doesn't return the same matrix: octave:1> x=randn(1,10); octave:1> (x>0) ans = Columns 1 through 8: 1 1 0 0 0 0 1 0 Columns 9 and 10: 1 1 octave:3> x(find(x>0)) ans = 0.93970 0.38451 0.30387 0.81479 2.46831  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 
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