[Octave-bug-tracker] [bug #33221] subsasgn without LHS should do in-place assignment for performance

[Rik]

Update of bug #33221 (project octave):

                  Status:               Need Info => Confirmed              
                 Summary: subsasgn without LHS assignment Matlab
incompatibility => subsasgn without LHS should do in-place assignment for
performance

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Follow-up Comment #2:

The optimization *may* be possible.  The operators such as '+=' or '-=' use
in-place optimization and are significantly faster.


octave:6> x = rand (1000,1000);
octave:7> tic; x = x + 1; toc
Elapsed time is 0.0022521 seconds.
octave:8> tic; x += 1; toc
Elapsed time is 0.00102091 seconds.


It already appears that indexing in the normal case is in-place.


octave:9> x = rand (1000,1000);
octave:10> tic; x(2,2) = 1; toc
Elapsed time is 2.69413e-05 seconds.
octave:11> idx = struct ("type", "()", "subs", {{2,2}});
octave:12> tic; subsasgn (x, idx, -1); toc
Elapsed time is 0.0146961 seconds.


Thus, it is a question of whether there is a way to hook in to the operator
based function or not.


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