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Edax

Edax is a very strong othello program. Its main features are:

• fast bitboard based & multithreaded engine.
• accurate midgame-evaluation function.
• opening book learning capability.
• text based rich interface.
• multi-protocol support to connect to graphical interfaces or play on Internet (GGS).
• multi-OS support to run under MS-Windows, Linux and Mac OS X.

Installation

From the release section of github, you must 7unzip both an executable of your favorite OS, and the evaluation weights (data/eval.dat) in the same directory. Only 64 bit executable with popcount support are provided.

Run

local

mkdir -p bin
cd src

# e.g. OS X sample
make build ARCH=x64 COMP=gcc OS=osx
cd ..
./bin/mEdax

docker

docker build . -t edax
docker run --name "edax" -v "$(pwd)/:/home/edax/" -it edax

cd /home/edax/
mkdir -p bin
cd src
make build ARCH=x64 COMP=gcc OS=linux

cd ..
curl -OL https://github.com/abulmo/edax-reversi/releases/download/v4.4/eval.7z # e.g. use v4.4 eval.dat
7z x eval.7z

./bin/lEdax-x64

Document

cd src
doxygen
open ../doc/html/index.html

=======

edax-reversi-AVX

Automatically exported from code.google.com/p/okuharaandroid-edax-reversi

This is SSE/AVX optimized version of Edax 4.4.0. Functionally equivalent to the parent project, provided no bugs are introduced.

64 bit version solves fforum-20-39 7% to 9% faster than the original 4.4.0 on my test. Thanks to AVX2, x64-modern build runs 14% faster on Haswell. 32 bit version runs 9% (Core2) to 20% (Athlon) faster than the original.

All SSE/AVX/MMX stuff belongs to board.c are moved into separate board_sse.c (for x64 and x86) and board_mmx.c (for x86) files.

I used GCC 4.7.2, Athlon X4 605e, Windows 8 (64) / XP (32), Clang 3.4, Core i5-4260U (Haswell), OSX 10.9.4 and Clang 1.7, Core2, OSX 10.6.8 for the benchmark.

1. Mobility (board_sse.c, board_mmx.c)

1.1 new SSE2 version of get_moves

Diagonals are SIMD'd using vertical mirroring by bswap.

Athlon -get_moves_sse
problem\fforum-20-39.obf: 111349635 nodes in 0:07.998 (13922185 nodes/s).
mobility: 81.10 < 81.28 +/- 0.17 < 82.03
Athlon +get_moves_sse
problem\fforum-20-39.obf: 111349635 nodes in 0:07.889 (14114544 nodes/s).
mobility: 71.08 < 71.72 +/- 0.34 < 73.53
Core2 -get_moves_sse
problem/fforum-20-39.obf: 111349635 nodes in 0:10.180 (10938078 nodes/s).
mobility: 78.06 < 78.18 +/- 0.08 < 78.41
Core2 +get_moves_sse
problem/fforum-20-39.obf: 111349635 nodes in 0:09.978 (11159514 nodes/s).
mobility: 60.84 < 61.19 +/- 0.13 < 61.47

1.2 can_move

Now calls SIMD'd get_moves for x86/x64 build.

2. Stability (board.c, board_sse.c, board_mmx.c)

2.1 get_full_lines_h, get_full_lines_v

get_full_lines for horizontal and vertical are simplified. The latter is compiled into rotation instrunction.

2.2 rearranged loop

The last while loop is rearranged not to call bit_count in case stable == 0.

2.3 new SSE2 version with bswap and pcmpeqb

Athlon -get_stability_sse
stability: 90.10 < 90.28 +/- 0.24 < 91.20
Athlon +get_stability_sse
stability: 81.59 < 81.93 +/- 0.73 < 86.25
Core2 -get_stability_sse
stability: 79.24 < 79.39 +/- 0.15 < 79.93
Core2 +get_stability_sse
stability: 71.80 < 71.85 +/- 0.06 < 72.07

2.4 get_corner_stability

Kindergarten version eliminates bit_count call.

2.5 find_edge_stable

Loop optimization and flip using carry propagation. One time execution but affect total solving time.

3. eval.c

Switch cases and table sizes are optimized. This small change slightly imploves endgame solving. I guess this should improve midgame too.

Athlon -eval
problem\fforum-20-39.obf: 111349635 nodes in 0:07.954 (13999200 nodes/s).
Athlon +eval
problem\fforum-20-39.obf: 111349635 nodes in 0:07.889 (14114544 nodes/s).
Core2 -eval
problem/fforum-20-39.obf: 111349635 nodes in 0:10.161 (10958531 nodes/s).
Core2 +eval
problem/fforum-20-39.obf: 111349635 nodes in 0:09.978 (11159514 nodes/s).

4. hash.c

I think hash->data.move[0] on line 677 should be hash->data.move[1].

5. board_symetry, board_unique (board.c, board_sse.c)

SSE optimization and mirroring reduction. (Not used in solving game)

6. AVX2 versions (x64-modern build only)

In many cases AVX2 version is simplest, thanks to variable shift instructions (although they are 3 micro-op instructions).

Benchmarks are on Core i5-4260U (Haswell) 1.4GHz (TB 2.7GHz) single thread.

4.4.0 original x64-modern clang
problem/fforum-20-39.obf: 111349635 nodes in 0:05.726 (19446321 nodes/s).
+optimizations 1-5 above, no-avx2
problem/fforum-20-39.obf: 111349635 nodes in 0:05.342 (20844185 nodes/s).
+get_moves (board_sse.c)
problem/fforum-20-39.obf: 111349635 nodes in 0:05.142 (21654927 nodes/s).
+flip_avx.c
problem/fforum-20-39.obf: 111349635 nodes in 0:04.946 (22513068 nodes/s).
+count_last_flip_sse.c
problem/fforum-20-39.obf: 111349635 nodes in 0:04.906 (22696624 nodes/s).

7. makefile

gcc-old, x86 build should be -m32, not -m64. Some flags and defines added for optimization.

b9d48c1 (Create README.md)