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Re: arend_1_34.1: Re: [gnugo-devel] 3.1.33 VC inconsistencies
From: |
Trevor Morris |
Subject: |
Re: arend_1_34.1: Re: [gnugo-devel] 3.1.33 VC inconsistencies |
Date: |
Sat, 20 Apr 2002 13:49:14 -0400 |
This patch does make aa_attackpats identical.
It also makes consistent owl_rot:66 and 13x13:63.
Great work.
I'm kicking off a full regression locally with this patch now.
I'm in favor of adding this to CVS, as it would be very nice to have the 3.2
engine behave identically cross-platform - remember, we'll continue to get
bug reports on it for a good 6-9 months probably.
Dan: Please drop me a line if you add this to CVS, and I'll run a full
regression
on the latest CVS for a VC build.
Other comments sprinkled below...
-Trevor
At 07:02 PM 4/20/2002 +0200, Arend Bayer wrote:
>On Sat, 20 Apr 2002, Trevor Morris wrote:
>
>> I've noticed one thing so far that's odd. Namely, aa_attackpats.c is
>> different
>> btw. VC & cygwin builds. You can see the VC version at:
>>
>> http://www.public32.com/pcolon/builds/gnugo/2002-4-19/gnugo/patterns/aa_attackpat.c
>>
>> The only other files that differ are eyes.c and the joseki files, but I
>> believe
>> this is CR/LF differences only. The differences in aa_attackpat.c look
>> substantive.
>
>I've done a quick web search, and it seems that for "release builds" (which
>Trevor is using IIRC) the VC compiler will inline functions if they seem
>suitable. (See
>http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccore/html/_core_.2f.Ob.asp
> )
I see the same behavior in debug builds, so this is probably not the cause.
>Then gg_normalize_float may well get inlined. As Gunnar pointed out
>correcting my floating point remarks, this function may no longer be safe
>in this case.
>
>This could explain the differences in aa_attack_pats.c, and although I
>couldn't quite parse the file, the diff seems to come from choosing
>different anchors. It should be corrected by the patch below.
>
>Are you sure that there were no differences in owl_*pat.c? I get a different
>sorting in the list of patterns if I break at the same point.
Yes, I'm quite sure. They were identical.
>This can have 2 reasons:
> * DFA matching found the patterns in a different order, most likely by
> a different database.
> * There might be some problem in the sorting in get_next_move_from_list;
> this does also use comparisons between identical floating point numbers.
> However, there is absolutely no computations done with these -- apart
> from a nonsense (int) conversion which is also eliminated in the
> patch below.
>
>
>Btw, as I see it there are 2 reasons to worry about platform dependencies:
> 1. They might be caused by bugs.
> 2. They are annoying for us when tuning against regressions.
>
>However, if we have eliminated 1., I don't think they are a problem for
>the stable release. In other words, in case this patch resolves the
>VC inconsistencies, I don't actually see the need to apply it before 3.3
>(and I would feel safer not to be responsible for such a very-last-minute
>change...).
As I said above, I think it's worth having the engines perform identically,
especially when we're really so close.
- [gnugo-devel] experimental_reading_1_33.1, bump, 2002/04/18
- Re: [gnugo-devel] experimental_reading_1_33.1, Gunnar Farneback, 2002/04/19
- Re: [gnugo-devel] experimental_reading_1_33.1, Daniel Bump, 2002/04/19
- Re: [gnugo-devel] experimental_reading_1_33.1, Gunnar Farneback, 2002/04/19
- Re: [gnugo-devel] experimental_reading_1_33.1, bump, 2002/04/19
- Re: [gnugo-devel] experimental_reading_1_33.1, Trevor Morris, 2002/04/19
- Re: [gnugo-devel] experimental_reading_1_33.1, bump, 2002/04/19
- [gnugo-devel] 3.1.33 VC inconsistencies, Trevor Morris, 2002/04/20
- arend_1_34.1: Re: [gnugo-devel] 3.1.33 VC inconsistencies, Arend Bayer, 2002/04/20
- Re: arend_1_34.1: Re: [gnugo-devel] 3.1.33 VC inconsistencies,
Trevor Morris <=
- Re: arend_1_34.1: Re: [gnugo-devel] 3.1.33 VC inconsistencies, bump, 2002/04/20
- Re: arend_1_34.1: Re: [gnugo-devel] 3.1.33 VC inconsistencies, Trevor Morris, 2002/04/20
- Re: [gnugo-devel] experimental_reading_1_33.1, Arend Bayer, 2002/04/20