Ticket #158 (closed defect: fixed)

Opened 5 years ago

Last modified 5 years ago

GNU Go doesn't get a basic endgame tesuji right

Reported by: rillig Owned by: gnugo
Priority: normal Milestone: 3.7.11
Component: source Version:
Severity: normal Keywords:
Cc: patch: yes

Description (last modified by rillig) (diff)

loadsgf tesuji1.sgf
1 reg_genmove black
#? [J2]

Attachments

tesuji1.sgf Download (182 bytes) - added by rillig 5 years ago.
The situation in which J2 is better than J3.
endgame_7_11.2.diff Download (4.7 KB) - added by nando 5 years ago.
endgame tuning (introducing the notion of "known safe move")
endgame_7_11.2a.diff Download (4.9 KB) - added by nando 5 years ago.
forgotten initialization fixed

Regression Results

Attachment Rev. PASS FAIL Nodes Status
endgame_7_11.2.diff Download never tested
endgame_7_11.2a.diff Download never tested

Change History

Changed 5 years ago by rillig

The situation in which J2 is better than J3.

comment:1 Changed 5 years ago by rillig

  • Description modified (diff)

Changed 5 years ago by nando

endgame tuning (introducing the notion of "known safe move")

comment:2 Changed 5 years ago by nando

  • patch set
  • Milestone changed from 3.8 to 3.7.11

Hi, the proposed patch introduces the notion of "known safe move" as discussed in endgame:980. Impact on performance is completely negligible (just a few more nodes over the whole regression suite) and results in the single (and expected) PASS in endgame:980

The newly proposed pattern EE201b would solve the case presented in this ticket alone, without that "known safe move" mechanism, but I wanted to kill two birds in a single shot and make the engine understand positions like  http://senseis.xmp.net/?YoseTesuji

Changed 5 years ago by nando

forgotten initialization fixed

comment:3 Changed 5 years ago by gunnar

  • Status changed from new to closed
  • Resolution set to fixed

The patch looks fine and has been added to the repository. I also included the proposed testcase after modifying it a bit so that there is an alternative 2 point gote move and balanced it so that the right move is the only move winning the game:











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