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Re: [gnugo-devel] engine/influence.c (and DFA)
From: |
Dave Denholm |
Subject: |
Re: [gnugo-devel] engine/influence.c (and DFA) |
Date: |
03 Sep 2002 19:25:26 +0100 |
Marco Scheurer <address@hidden> writes:
> On Tuesday, September 3, 2002, at 06:11 pm, Arend Bayer wrote:
> > On Tue, 3 Sep 2002, Marco Scheurer wrote:
> >
> >> Speaking of micro optimizations and speed/space trade offs, I've been
> >> wondering about these:
> >>
> >> - There are many bi-dimensional arrays. Would it make sense to replace
> >> them by pointers to pointers? Two indirections are supposed to be
> >> faster
> >> than the arithmetic needed to access elements in a bi-directional
> >> array.
> >> The syntax to read an element is the same, but some initialization code
> >> is needed.
> >
> > I think in all performance relevant spots (maybe with the exception of
> > influence.c), we are using one-dimensional arrays since the
> > 1D-transition by Gunnar and Inge early in 3.1.x.
>
> influence.c still has bidimensional arrays, I think, and even with the
> 1D transition you still have a multiplication, don't you? Based on what
> I read a (probably too long) while ago in Numerical Recipes in C, double
> indirection was faster than multiply, at least on Pentium.
>
I think cpu performance has increased much faster than memory speed..?
dd
--
address@hidden http://www.insignia.com
- [gnugo-devel] engine/influence.c (and DFA), Dave Denholm, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA), Arend Bayer, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA), Dave Denholm, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA), Evan Berggren Daniel, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA), Arend Bayer, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA), Marco Scheurer, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA), Dave Denholm, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA), Arend Bayer, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA), Marco Scheurer, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA), Gunnar Farneback, 2002/09/03
- Re: [gnugo-devel] engine/influence.c (and DFA),
Dave Denholm <=
- Re: [gnugo-devel] engine/influence.c (and DFA), Heikki Levanto, 2002/09/03
- HAVE_INLINE (Re: [gnugo-devel] engine/influence.c (and DFA)), Arend Bayer, 2002/09/03
- Re: HAVE_INLINE (Re: [gnugo-devel] engine/influence.c (and DFA)), Marco Scheurer, 2002/09/03
- Re: HAVE_INLINE (Re: [gnugo-devel] engine/influence.c (and DFA)), Arend Bayer, 2002/09/03
- Re: HAVE_INLINE (Re: [gnugo-devel] engine/influence.c (and DFA)), Marco Scheurer, 2002/09/03
- Re: HAVE_INLINE (Re: [gnugo-devel] engine/influence.c (and DFA)), Trevor Morris, 2002/09/06
- Re: [gnugo-devel] engine/influence.c (and DFA), Dave Denholm, 2002/09/03
Re: [gnugo-devel] engine/influence.c (and DFA), Gunnar Farneback, 2002/09/03