Fairy-Max 4.8V
Posted: Thu Oct 23, 2014 9:08 am
It turns out that the enhanced bare-King mating patch of Fairy-Max 4.8U contained a bug, which broke the search depth for orthodox Chess. (It always switched off null move, rather than just against a bare King, as was intended.) Thanks to Colin Jenkins for noticing this!
So I released a new version 4.8V which fixes this. For the time being it can be downloaded only from
http://hgm.nubati.net/fairymax.zip
which contains the fmax.exe, fmax.ini and logo.bmp. In due time I will probably also replace the version in the WinBoard installer.
This time I tested the new version for playing strength in normal Chess; it scored an exact wash (200-200) against 4.8S at 1-min sudden death, and a 56.5-43.5 win at 40 moves/min, which seems OK.
(Just in case you wonder why there doesn't seem to be an improvement in playing strength due to the new features: bare-King mating in Chess is so easy that it doesn't need the patch, because you almost always have a Q or R to do it, and the only difficult case for which the patches were needed, KBNK, does virtually never occur. This is different in Makruk, however, where Pawns promote to an almost equally worthless 1-step diagonal mover, so that almost no game ends with decent mating potential, and you will have to perform a mate with a horde of nearly worthless pieces. The bare-King patch was needed to make that possible.)
So I released a new version 4.8V which fixes this. For the time being it can be downloaded only from
http://hgm.nubati.net/fairymax.zip
which contains the fmax.exe, fmax.ini and logo.bmp. In due time I will probably also replace the version in the WinBoard installer.
This time I tested the new version for playing strength in normal Chess; it scored an exact wash (200-200) against 4.8S at 1-min sudden death, and a 56.5-43.5 win at 40 moves/min, which seems OK.
(Just in case you wonder why there doesn't seem to be an improvement in playing strength due to the new features: bare-King mating in Chess is so easy that it doesn't need the patch, because you almost always have a Q or R to do it, and the only difficult case for which the patches were needed, KBNK, does virtually never occur. This is different in Makruk, however, where Pawns promote to an almost equally worthless 1-step diagonal mover, so that almost no game ends with decent mating potential, and you will have to perform a mate with a horde of nearly worthless pieces. The bare-King patch was needed to make that possible.)