Re: slow char({str})

[Daniel J Sebald]

Jaroslav Hajek wrote:

> > > Please check
> > > http://hg.savannah.gnu.org/hgweb/octave/rev/4ff6f8efdda2
> > >
> > > also transplanted into 3.2.x.
> > >
> > > thanks
> >
> > Very nice Jaroslav.  Which of these changes is the speedup coming from?
> > This hunk
> >
> > -       elem (i, j) = s[i][j];
> > +       elem (i, j) = si[j];
> >
> > shouldn't have been too much as there is only a little extra computation in
> > the indexing before the change.
>
>
> No. In fact, this *was* the bottleneck, changing a linear complexity
> operation to quadratic one. Welcome to the world of COW magic.

Oh yeah, s is a reference, not a pointer...

What does COW stand for, other than can of worms?

Dan