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shape of x(y)
From: 
John W. Eaton 
Subject: 
shape of x(y) 
Date: 
Tue, 1 Aug 2000 21:15:07 0500 (CDT) 
On 1Aug2000, Andy Adler <address@hidden> wrote:
 I'm trying to figure out the rules
 octave uses for index expressions of type: x(y)

 They seems to be quite complicated, this
 is what I could figure out.

 x is matrix: result is same shape as y
 x is vector: result is same orientation as x
 x is scalar: result is column orientation

 Is this correct?
Close, but in the last case, Octave actually uses the value of
prefer_column_vectors to decide whether to create a row or column
vector. But that will likely change, since now I see it is not
compatible with Matlab, even if prefer_column_vectors is set to 0.
 I need to know so that I can
 make the sparse functions do the same thing
 as the current "full" matrix rules.

 Additionally, I find these rules unecessarily
 complicated. Wouln't a rule like:
 result is same shape as y
 work in all cases?
No, because then I don't think it would be compatible with Matlab. It
appears that Matlab now returns
x is matrix: result is same shape as y
x is vector: result is same orientation as x
x is scalar: result is same shape as y
 Or this this another example of bugforbug
 MATLAB compatibility?
Maybe, only it seems it is no longer compatible either (I thought that
it once was, at least if prefer_column_vectors was set to 0).
jwe

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 shape of x(y), Andy Adler, 2000/08/01
 shape of x(y),
John W. Eaton <=