[Octave-bug-tracker] [bug #31742] sqp: incorrect order of removal of Inf bounds

[Olaf Till]

Follow-up Comment #6, bug #31742 (project octave):

Thanks for the thorough review.

The first issue (scalar bounds) is resolved in the now attached patch
(without expanding the scalar bounds).

The third suggestion (isinf() ->  ==) is also in the new patch. I did not
know that == is overloaded for +-Inf in current Octave, it was not so before.

I did not follow your second suggestion (global variables) for the following
reasons:

1. I don't think global variables give a speed advantage, see this test:


octave:1> function f_global (x)
> global y;
> for id = 1:1000
> x == y;
> endfor
> endfunction
octave:2> function f_anonymous (x, y)
> for id = 1:1000
> x == y;
> endfor
> endfunction
octave:3> global y;
octave:4> y = 1;
octave:5> z = 1;
octave:6> af = @ (x) f_anonymous (x, z);
octave:7> tic; f_global (1), toc
Elapsed time is 0.00171609 seconds.
octave:8> tic; af (1), toc
Elapsed time is 0.00165111 seconds.
octave:9> tic; f_global (1), toc
Elapsed time is 0.00172499 seconds.
octave:10> tic; af (1), toc
Elapsed time is 0.00164196 seconds.
octave:11> tic; f_global (1), toc
Elapsed time is 0.00170795 seconds.
octave:12> tic; af (1), toc
Elapsed time is 0.00164512 seconds.
octave:13> 


2. I think the original author used global variables simply because
anonymouns function were not available in Octave at this time.

3. The most important point: Global variables break recursive calls of sqp.
But recursive optimization is sometimes necessary. I think all global
variables in sqp have to be replaced by using anonymous functions in the
future. So I would not add a further global variable now.


(file #22192)
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Additional Item Attachment:

File name: sqp-3rd-inf-bounds-removal.changeset Size:4 KB


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