de Man's Stockfish syzygy is faster than normal version!

Discussion of chess software programming and technical issues.

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phenri
Posts: 284
Joined: Tue Aug 13, 2013 9:44 am

Re: de Man's Stockfish syzygy is faster than normal version!

Post by phenri »

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56273#c13

I give up. We have to live with this false positive.
:)
syzygy
Posts: 5713
Joined: Tue Feb 28, 2012 11:56 pm

Re: de Man's Stockfish syzygy is faster than normal version!

Post by syzygy »

BBauer wrote:IMHO not all warnings are bogus. Bound crossings are to be taken serious.
No bounds are crossed. That's why they are bogus warnings.
syzygy
Posts: 5713
Joined: Tue Feb 28, 2012 11:56 pm

Re: de Man's Stockfish syzygy is faster than normal version!

Post by syzygy »

BBauer wrote:The files are running well with 5-pieces.
They are corrupted when using full 6-pieces.
What do you mean with "they are corrupted when using"?

The files are corrupted or the files are not corrupted.
"when using them" has not much to do with that.

Please check them using fsum and the checksums found here:
http://kirill-kryukov.com/chess/tablebases-online/
BBauer
Posts: 658
Joined: Wed Mar 08, 2006 8:58 pm

Re: de Man's Stockfish syzygy is faster than normal version!

Post by BBauer »

Paul wrote
Can be improperly downloaded, check the files if they are not corrupted

My silly note was meant to Paul.
-------------------------------------

The bases I use were never downloaded, but generated and seam to be correct. Anyway I will checksum them later.

In http://abrok.eu/stockfish/comment comment518 I wrote
With the latest version I get compiler warnings

g++ -Wall -Wcast-qual -fno-exceptions -fno-rtti -fprofile-generate -ansi -pedantic -Wno-long-long -Wextra -Wshadow -DNDEBUG -O3 -DIS_64BIT -msse -DUSE_BSFQ -msse3 -DUSE_POPCNT -flto -c -o thread.o thread.cpp

tbprobe.cpp: In function ‘probe_ab(Position&, int, int, int*)’:
tbprobe.cpp:191:7: warning: array subscript is above array bounds [-Warray-bounds]
p[i++] = pop_lsb(&bb) ^ mirror;
^
g++ -Wall -Wcast-qual -fno-exceptions -fno-rtti -fprofile-generate -ansi -pedantic -Wno-long-long -Wextra -Wshadow -DNDEBUG -O3 -DIS_64BIT -msse -DUSE_BSFQ -msse3 -DUSE_POPCNT -flto -c -o timeman.o timeman.cpp
tbprobe.cpp:191:7: warning: array subscript is above array bounds [-Warray-bounds]
g++ -Wall -Wcast-qual -fno-exceptions -fno-rtti -fprofile-generate -ansi -pedantic -Wno-long-long -Wextra -Wshadow -DNDEBUG -O3 -DIS_64BIT -msse -DUSE_BSFQ -msse3 -DUSE_POPCNT -flto -c -o tt.o tt.cpp
tbprobe.cpp: In function ‘Tablebases::probe_dtz(Position&, int*)’:
tbprobe.cpp:301:7: warning: array subscript is above array bounds [-Warray-bounds]
p[i++] = pop_lsb(&bb) ^ mirror;
^
tbprobe.cpp:301:7: warning: array subscript is above array bounds [-Warray-bounds]

compiler:gcc version 4.8.1 20130909 [gcc-4_8-branch revision 202388] (SUSE Linux)

Why would someone ignore "warning: array subscript is above array bounds [-Warray-bounds] "

Had you a look at these lines?
Kind regards
Bernhard
syzygy
Posts: 5713
Joined: Tue Feb 28, 2012 11:56 pm

Re: de Man's Stockfish syzygy is faster than normal version!

Post by syzygy »

I thought I have been clear enough?

As I told you, they are BOGUS. Of course I looked at them. They have been there since forever but only with gcc-4.8.x. This compiler is KNOWN to issue BOGUS array-bound warnings. gcc-4.8.x is lying through its teeth.

Is this clear now?

Just switch to gcc-4.7 or add -Wno-array-bounds to the compiler flags.
BBauer
Posts: 658
Joined: Wed Mar 08, 2006 8:58 pm

Re: de Man's Stockfish syzygy is faster than normal version!

Post by BBauer »

Yes, you were clear enough! And you were right.
Exactly one of my files was corrupted and it was KBPPvKB.rtbw
So its clear that the position I posted

[D}8/3Pb1p1/8/3P2P1/5P2/7k/4K3/8 w - - bm Kd3; id "E_E_T 007 - B vs L";[d]
failed.
Sorry for the fuss
kind regards
Bernhard
syzygy
Posts: 5713
Joined: Tue Feb 28, 2012 11:56 pm

Re: de Man's Stockfish syzygy is faster than normal version!

Post by syzygy »

BBauer wrote:Exactly one of my files was corrupted and it was KBPPvKB.rtbw
Ok, good that this has been solved.

Since you generated them yourself you probably have the tbcheck program too. If you want to know if something went wrong during the generation, you could try:

Code: Select all

tbcheck KBPPvKB.rtbw
If you get FAIL!, then the generation probably went fine, but the file got corrupted afterwards. For example when copying from one disk to another, or maybe the disk has a bad block.

If you get OK!, then the file is still identical to how it was when immediately after it was generated. That means something went wrong during the generation.
BBauer
Posts: 658
Joined: Wed Mar 08, 2006 8:58 pm

Re: de Man's Stockfish syzygy is faster than normal version!

Post by BBauer »

I have downloaded the KBPPvKB.rtbw from
http://tablebase.sesse.net/syzygy/6-WDL/
Since my complete system has changed I can no longer generate files myself.
Thank you for your willingness to help.
Now everything works as expected.
Kind regards
Bernhard