From help-octave-request at bevo dot che dot wisc dot edu  Thu Dec 16 10:25:15 1999
Subject: manipulation of matrix elements
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Michael Roth <mike at aug dot ig dot erdw dot ethz dot ch>
Cc: help-octave at bevo dot che dot wisc dot edu
Date: Thu, 16 Dec 1999 10:24:52 -0600 (CST)

On 16-Dec-1999, Michael Roth <mike at aug dot ig dot erdw dot ethz dot ch> wrote:

| I tried to set a lower limit for matrix elements using the find command.
| I think there is a bug. Have a look at the following lines:     
| 
| s=rand(2)
| s =
|   0.47926  0.89733
|   0.77293  0.02806
| 
| >> [i,j]=find(s<=0.5)
| i =
|   1
|   2
| 
| j =
|   1
|   2
| 
|                        
| >> s(i,j)=0.5                 | In Matlab, this command gives 
| s =                           | s =  
|   0.50000  0.50000            |   0.50000  0.89733
|   0.50000  0.50000            |   0.77293  0.50000

What version of Matlab does this?

If Matlab *does* behave this way, I think it is a bug in Matlab, not
Octave, because it leads to an ambiguity depending on the sizes of the
index vectors.

I think what you want to write is

  i = find (x <= 0.5);
  s(i) = 0.5;

which should work in a compatible way if do_fortran_indexing is set to
a non-zero value.

jwe



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