Endgame

[sanxiyn]

gnugo plays A8 and lose. It should play A7!

[nando]

The move at A8 is overvalued, because

• per pattern EE401, it is considered a strategic defense of B8
• the dragon B8 is considered a tiny bit weak, or said differently, it is seen as not completely safe: "only" 2 certain eyes, where the weakness computation (see crude_dragon_weakness() and the genus2weakness[] array in dragon.c) only considers 3 eyes or more as 100% safe.

Possible solutions:

• remove the d class from all endgame patterns, on the basis that those usually lack enough context information to make such a call (on the other hand, someone probably had a reason to put those there...)
• improve weakness and/or genus evaluation (clearly, that's easier said than done)

Sanxiyn, is it difficult for you to group those problems and submit them as patches for the regression suite ?

[gunnar]

Patch making a testcase for the position.

[gunnar]

The testcase has been committed now although the actual problem isn't solved. Closing the ticket.