[Kst] extragear/graphics/kst/patches

George Staikos staikos at kde.org
Tue Nov 1 01:56:10 CET 2005

On Monday 31 October 2005 19:38, Barth Netterfield wrote:
> How much speed up do you get?

   This is not easy to judge yet.  It might take a profiler to get meaningful 
results.  Actually, I think the real gain is in lower CPU usage because we're 
blocking on X again.  I've removed almost all the limitations I could find on 
our side now.

> > A patch to implement a short-cut interpolation in the hot spots in curve
> > plotting.  It removes a function call (inlines it) and two branches, one
> > of which has a disjunction, neither of which are likely.  However it's
> > slightly incomplete because it can cause invalid memory accesses if the
> > vectors have size == 1 and it tries to plot them.
> >
> > The easy solution is to
> > plot nothing if one of the vectors has size == 1, but I suspect that's
> > undesired.
> We need to be able to plot a single x,y point.

  Originally I was going to implement specifically this case and nothing else, 

> But in 'line' mode, I can't see that we would ever need to plot a curve
> with only one point in one of the vectors.  So we could have two
> interpolates: one for w/ lines and one for w/ points.

  I was thinking of a case of X vector [0,...,n] and Y vector [5] which should 
give a straight line at 5 from 0..n.  Again, we could shortcut this case and 
its complement, but maybe there are other other weird cases too.  The same 
applies to error bars, bar graphs, etc.

George Staikos
KDE Developer				http://www.kde.org/
Staikos Computing Services Inc.		http://www.staikos.net/

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