CT800 V1.12 released

[Ras]

I have released version 1.12 of the CT800. Sources are included as always. The most important changes:

• Fixed endings with opposite coloured bishops so that the Kings' positions do not outweigh an additional pawn loss.
• Fixed a bug that prevented the detection of 50 moves draw in the search tree.
• The draw avoidance during the early middle game checks more thoroughly whether or not to allow draw by repetition.
• Selective deepening when pushing passed pawns in the endgame.
• Draw detection with KP:KQ and KP:KR with pawn on 7th/2nd rank and distant king of the Q/R side.
• The time for the pre-sorting phase has been reduced by about 30%, and it gives a mini-PV.
• Quiescence includes check evasions.
• The mate search mode is about 30% faster.
• Rewritten the time management; changing sides under time controls is now possible.
• The CPU speed can be adjusted in several steps from 10% to 140% (10%, 25%, 50%, 75%, 100%, 120%, 140%), except for the pre-sorting phase.
• More opening knowledge.
• Manual updated accordingly.

For the PC version:

• The engine can throttle the virtual CPU speed from 100% down to 1% in an energy-friendly way, except for the pre-sorting phase. Controlled with an UCI command.
• The display of the currently examined root move can be toggled between continuous mode and once per second.
• Fixed the "easy move detection".
• Fixed the lazy eval enabling in the middle game.
• Additional platform support for Android 4.1 or higher (geared at "Chess for Android" or "Droidfish") and Raspberry Pi 1/2/3/Zero with Debian Jessie. Ready-made binaries are supplied.
• No iOS support planned because Apple has decided that iOS users don't need GPL'ed software.
• The PC-Linux version has been tested under Knoppix 7.7.1. No binaries supplied because that's difficult with Linux, but sources and build scripts are what Linux users usually prefer anyway.
• For Windows, EXE files are supplied as both 32 bit and 64 bit. No change, just saying. Now with icons for the EXEs.
• Added UCI support, including arbitrary tabs/spaces, case insensitive (except for parts of the FEN string, of course), searchmoves, nodes, mate. Only pondering is not implemented, but the engine still can cope with "go ponder" / "ponderhit".
• Removed Winboard support.

Yes, the CT800 has changed to the dark (UCI) side - but they have the better ecosystem, which amounts to having cookies.

Website: https://www.ct800.net/sw_release_v112.htm
Direct download: https://www.ct800.net/download/ct800-v1.12.zip

[main line]

How much Stockfish's paches included in this release ?

[Ras]

How much Stockfish's paches included in this release ?

Exactly 0. The engine is in a completely different range (around 2200) than Stockfish. However, Stockfish cannot be ported to a Cortex M4 microcontroller (1 MB flash-ROM, 192 kB RAM) running without operating system, which is the main point of this project. The PC version came as per user requests and now also serves as testbed.

The original baseline was NG-Play by George Georgopoulos, with vast modifications. The KPK bitbase by Marcel van Kervinck is also part of the project. The AUTHORS.txt file, included in the project, lists that to give proper credit, as well as the source files. The CT800 project fully complies to the respective licence terms.

Even the website is clear about who contributed what, see https://www.ct800.net/summary.htm#sw , and the downloadable manual also reproduces that.

[Jamal Bubker]

Thank you Rasmus