From help-request at octave dot org Fri Sep  3 09:43:16 2004
Subject: Re: Create a logical array of 0
From: Stefan van der Walt <stefan at sun dot ac dot za>
To: help at octave dot org
Cc: Josep Mon?s i Teixidor <jmones at puntbarra dot com>,         "Llista help a octave.org" <help@octave.org>
Date: Fri, 3 Sep 2004 16:42:09 +0200

My version of MATLAB uses uint8 for black and white pictures, so there
should be no need to accommodate 'logical'.

Regards
Stefan

On Fri, Sep 03, 2004 at 04:23:02PM +0200, David Bateman wrote:
> According to Josep Mon?s i Teixidor <jmones at puntbarra dot com> (on 09/03/04):
> > Hi!
> > 
> > How can I create a logical array of zeros without conversions between
> > types?
> > 
> > If tried zeros(m,n,"logical") but didn't work for logical.
> > 
> > I'm currently using logical(zeros(m,n)) but I think this makes a
> > conversion from double to bool (or it is smart enough to handle it?)
> > 
> > Thanks in advance, 
> 
> Err, I just added code like zeros(m,n,"int8") about a week ago that got into
> 2.1.58, I didn't think about "logical". Reading the man-pages for zeros in
> matlab at
> 
> http://www.mathworks.com/access/helpdesk/help/techdoc/ref/zeros.html
> 
> The allowed types are
> 
> 'double', 'single', 'int8', 'uint8', 'int16', 'uint16', 'int32', or 'uint32'.
> 
> as 'single' precision is not in octave at the moment, and taking this as a
> reference zeros(m,n,classname) only works for the above classname minus
> 'single'.
> 
> The only version of matlab (R12) I have access to doesn't allow this
> syntax, but instead treats the third argument as a numerical value and
> creates a three dimensional matrix.
> 
> Given the above reference I don't beleieve Matlab itself can handle 
> zeros(m,n,'logical'). If your problem is memory then something like
> logical(zeros(m,n,'int8')) should help..
> 
> D.
> 



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