This is a modified compile of Stockfish 9 (“Stockfish 9 C0”) for Windows that sets the default contempt to ‘0.’
The official Stockfish 9 is set with a default contempt value of ’20’ (20 centipawns), which may increase engine ELO in games against weaker engines, but isn’t helpful for serious analysis.
You can always change the contempt value in the UCI options if you want to tinker with different settings. See:
With this compile, however, I have removed the need for anyone to modify the UCI options. I suspect the official version with contempt=20 ‘enabled’ will be stronger in engine-engine play, but those interested primarily in analysis might consider using this compile as well.
Because the file name and internal name are different from the official release, you should be able to install it in ChessBase / Fritz as a separate engine and without any problems.
Two changes to the official Stockfish 9 source code are included in this compile:
o[“Contempt”] << Option(20, -100, 100);
o[“Contempt”] << Option(0, -100, 100);
in ucioption.cpp line 62
const string Version = “9”;
const string Version = “9 C0”;
in misc.cpp line 54
The official source code is available at:
It is also provided in this zip file.
Which version should you use?
stockfish_9_x64_bmi2_analysis.exe — for Haswell+ Intel processors
stockfish_9_x64_popcnt_analysis.exe — for ‘modern’ AMD and Intel processors. Use this with Ryzen chips.
stockfish_9_x64_analysis.exe — for generic 64 bit CPUs.
stockfish_9_x32_analysis.exe — for 32 bit CPUs.
These files were compiled using MinGW (64-bit) and GCC 7.2.0 on a Windows 8.1 machine. No warranty is made or implied with these engines – use at your own risk.