Re: unexpected copying

[John W. Eaton]

On 13-Jun-2006, Paul Kienzle wrote:

| Thanks! Your workaround works in 2.1.72 as well:
| 
|     A = reshape(A,newshape);
|     1; # Drop extra reference to A (Octave 2.9.6 and below)
|     A(1,1) = 2;

OK, I also made this change to the 2.1.x sources in case we decide to
make a 2.1.74 snapshot.

| Here's another one which I suspect will be harder to avoid:
| 
|    function t = set1(A), tic; A(1,1)=2; t=toc; end
|    S=T=[100:100:3000];
|    for i=1:length(S); T(i) = set1(rand(S(i))); end
|    plot(S,T);
| 
| I'm guessing the argument list is holding onto a reference
| to the temporary rand(S(i)) until the function call returns.
| 
| It's probably not worth your time addressing this since
| it won't help the common case:
| 
|    function t = set1(A), tic; A(1,1)=2; t=toc; end
|    S=T=[100:100:3000];
|    for i=1:length(S); A=rand(S(i)); T(i) = set1(A); end
|    plot(S,T);

Right, I don't see how to avoid these copies without rewriting much of
Octave.

jwe