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C# Performance
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Sven Schüle



Joined: 15 May 2008
Posts: 2249
Location: Berlin, Germany
PostPost subject: Re: C# Performance    Posted: Fri Feb 03, 2012 9:45 am Reply to topic Reply with quote
RoadWarrior wrote:
micron wrote:
You may want to consider a suggestion made earlier in the thread: when deciding whether a castling move can be generated, be sure to get the order of tests right:
Code:
if ( IntermediateSqsNotObstructed() /*fast*/ && IntermediateSqsNotAttacked() /*slow*/ )
       { GenerateCastlingMove() }


Here's a fragment from my move generation showing that I already do this:

Code:
// If Black can still castle kingside...
if ((this.PropertyStore.BlackCastlingStatus & Constants.EnumCastlingStatus.CAN_CASTLE_OO) != 0)
{
  // If the Black kingside castling squares (F8/G8) aren't occupied...
  if ((Constants.MASK_FG[Constants.MOVE_BLACK] & this.OccupiedSquares) == 0)
  {
    // If the Black king and kingside castling squares (E8/F8) aren't under attack...
    if (!this.IsAttacked(Constants.MASK_EF[Constants.MOVE_BLACK], true))
    {
      // Pseudo-legal: we'll find out later if King has castled into check.
      moveList.Add(Constants.CASTLING_BLACK_OO);
    }
  }
}


But I agree with you, it does look like the IsAttacked method needs some optimisation. At the moment, it meets my performance budget, but that's likely to change in the near future.

Testing attacks to E8 is the same as testing whether the king is in check before castling. If you already do this within your perft() or search() prior to move generation then keeping an inCheck flag and accessing it in the move generator will save double work, since no castling generation needs to be tried at all if the king is in check.

If you don't have this inCheck information available in the move generator then there is still some potential for improvement since you are doing the test for attacks to E8 twice, for black short castle and for black long castle (if both are still available and intermediate squares are empty), but need it only once. You might still want to perform the faster parts first (castling right available + no obstruction) so doing it this way will be somehow tricky. But I think you will need the "inCheck" prior to move generation anyway at some point, which would make these thoughts obsolete.

Testing attacks to F8 might be postponed, too, until actually making the move but depending on your implementation this might require more branching since it is a test in addition to "king was left in check" that must be done only for castling moves. For this reason I prefer to do it the same way as you do.

Sven
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Subject Author Date/Time
C# Performance Richard Allbert Fri Jan 27, 2012 8:41 pm
      Re: C# Performance Kevin Hearn Fri Jan 27, 2012 9:01 pm
            Re: C# Performance Richard Allbert Fri Jan 27, 2012 9:13 pm
      Re: C# Performance Gary Fri Jan 27, 2012 9:07 pm
            Re: C# Performance Richard Allbert Fri Jan 27, 2012 9:17 pm
                  Re: C# Performance Gary Fri Jan 27, 2012 10:09 pm
      Re: C# Performance Mark Pearce Sat Jan 28, 2012 12:59 am
            Re: C# Performance Richard Allbert Sat Jan 28, 2012 8:44 am
                  Re: C# Performance Sven Schüle Sat Jan 28, 2012 9:48 am
                        Re: C# Performance Richard Allbert Sat Jan 28, 2012 10:25 am
                              Re: C# Performance Richard Allbert Sat Jan 28, 2012 11:41 am
                  Re: C# Performance Mark Pearce Sat Jan 28, 2012 11:44 am
            Re: C# Performance Richard Allbert Sat Jan 28, 2012 10:31 am
      Re: C# Performance Marco Costalba Sat Jan 28, 2012 1:09 pm
            Re: C# Performance Lucas Braesch Sat Jan 28, 2012 1:52 pm
            Re: C# Performance Richard Allbert Sat Jan 28, 2012 2:05 pm
                  Re: C# Performance Marco Costalba Sat Jan 28, 2012 2:30 pm
                        Re: C# Performance Richard Allbert Sat Jan 28, 2012 5:22 pm
                              Re: C# Performance Sven Schüle Sat Jan 28, 2012 6:02 pm
                                    Re: C# Performance Richard Allbert Sat Jan 28, 2012 6:12 pm
                                    Re: C# Performance Robert Purves Sat Jan 28, 2012 10:17 pm
                              Re: C# Performance Marco Costalba Sat Jan 28, 2012 10:25 pm
                  Re: C# Performance Thomas Petzke Sat Jan 28, 2012 4:21 pm
      Re: C# Performance Richard Allbert Mon Jan 30, 2012 12:52 pm
            Re: C# Performance Marco Costalba Mon Jan 30, 2012 6:37 pm
                  Re: C# Performance Richard Allbert Wed Feb 01, 2012 6:55 pm
                        Re: C# Performance Marco Costalba Wed Feb 01, 2012 7:18 pm
            Re: C# Performance Mark Pearce Mon Jan 30, 2012 9:55 pm
                  Re: C# Performance Richard Allbert Wed Feb 01, 2012 6:57 pm
                        Re: C# Performance Mark Pearce Wed Feb 01, 2012 9:59 pm
            Re: C# Performance Mark Pearce Fri Feb 03, 2012 1:34 am
                  Re: C# Performance Robert Purves Fri Feb 03, 2012 3:26 am
                        Re: C# Performance Mark Pearce Fri Feb 03, 2012 9:28 am
                              Re: C# Performance Sven Schüle Fri Feb 03, 2012 9:45 am
                                    Re: C# Performance Mark Pearce Sat Feb 04, 2012 7:57 pm
                                          Re: C# Performance Sven Schüle Sat Feb 04, 2012 10:36 pm
                                                Re: C# Performance Mark Pearce Sat Feb 04, 2012 11:49 pm
                                                      Re: C# Performance Sven Schüle Sun Feb 05, 2012 12:51 am
                                                            Re: C# Performance Mark Pearce Sun Feb 05, 2012 1:05 am
                              Re: C# Performance Sven Schüle Fri Feb 03, 2012 10:04 am
                                    Re: C# Performance Mark Pearce Fri Feb 03, 2012 11:40 am
                                          Re: C# Performance Richard Allbert Sat Feb 04, 2012 7:10 pm
                                                Re: C# Performance Lucas Braesch Sat Feb 04, 2012 8:31 pm
                                                      Re: C# Performance Mark Pearce Sat Feb 04, 2012 10:23 pm
                                                            Re: C# Performance Mark Pearce Sun Feb 05, 2012 12:23 am
                                                                  Re: C# Performance Lucas Braesch Sun Feb 05, 2012 2:57 am
                                                                        Re: C# Performance Mark Pearce Sun Feb 05, 2012 11:40 am
                                                                              Re: C# Performance Richard Allbert Mon Feb 06, 2012 6:29 pm
                                                                                    Re: C# Performance Richard Allbert Mon Feb 06, 2012 6:29 pm
                                                                                          Re: C# Performance Richard Allbert Mon Feb 06, 2012 6:30 pm
                                                                                          Re: C# Performance Richard Allbert Mon Feb 06, 2012 6:45 pm
                                                                                          Re: C# Performance Gary Mon Feb 06, 2012 7:00 pm
                                                                                          Re: C# Performance Richard Allbert Mon Feb 06, 2012 7:12 pm
                                                                                          Re: C# Performance Sven Schüle Mon Feb 06, 2012 10:50 pm
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 9:52 am
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 9:53 am
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 9:53 am
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 9:54 am
                                                                                          Re: C# Performance Mark Pearce Tue Feb 07, 2012 1:59 pm
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 2:54 pm
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 3:06 pm
                                                                                          Re: C# Performance Mark Pearce Tue Feb 07, 2012 5:17 pm
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 6:10 pm
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 6:20 pm
                                                                                          Re: C# Performance Mark Pearce Tue Feb 07, 2012 8:02 pm
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 9:19 pm
                                                                                          Re: C# Performance Mark Pearce Tue Feb 07, 2012 10:20 pm
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 7:47 am
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 7:57 am
                                                                                          Re: C# Performance Sven Schüle Wed Feb 08, 2012 10:09 am
                                                                                          Re: C# Performance Mark Pearce Wed Feb 08, 2012 12:16 pm
                                                                                          Re: C# Performance Vincent Diepeveen Sat Feb 18, 2012 10:03 pm
                                                                                          Re: C# Performance Mark Pearce Wed Feb 08, 2012 9:30 am
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 12:02 pm
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 12:34 pm
                                                                                          Re: C# Performance Mark Pearce Wed Feb 08, 2012 12:56 pm
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 1:18 pm
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 2:30 pm
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 2:34 pm
                                                                                          Re: C# Performance Mark Pearce Wed Feb 08, 2012 3:02 pm
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 3:27 pm
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 3:29 pm
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 3:59 pm
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 4:04 pm
                                                                                          Re: C# Performance Mark Pearce Wed Feb 08, 2012 6:07 pm
                                                                                          Re: C# Performance Richard Allbert Thu Feb 09, 2012 10:41 am
                                                                                          Re: C# Performance Mark Pearce Thu Feb 09, 2012 1:47 pm
                                                                                          Re: C# Performance Richard Allbert Thu Feb 09, 2012 2:56 pm
                                                                                          Re: C# Performance Mark Pearce Sat Feb 11, 2012 4:41 pm
                                                                                          Re: C# Performance Richard Allbert Sun Feb 12, 2012 8:34 am
                                                                                          Re: C# Performance Lucas Braesch Sun Feb 12, 2012 10:52 am
                                                                                          Re: C# Performance Richard Allbert Sun Feb 12, 2012 12:26 pm
                                                                                          Re: C# Performance Ron Murawski Mon Feb 13, 2012 5:26 am
                                                                                          Re: C# Performance Lucas Braesch Mon Feb 13, 2012 5:52 am
                                                                                          Re: C# Performance Richard Allbert Mon Feb 13, 2012 6:27 am
                                                                                          Re: C# Performance Ron Murawski Tue Feb 14, 2012 6:38 am
                                                                                          Re: C# Performance Lucas Braesch Tue Feb 14, 2012 8:22 am
                                                                                          Re: C# Performance Mark Pearce Tue Feb 14, 2012 11:30 pm
                                                                                          Re: C# Performance Richard Allbert Thu Feb 16, 2012 10:49 am
                                                                                          Re: C# Performance Mark Pearce Sat Feb 18, 2012 12:34 pm
                                                                                          Re: C# Performance Richard Allbert Mon Feb 20, 2012 9:19 pm
                                                                                          Re: C# Performance Mark Pearce Tue Feb 21, 2012 8:33 am
                                                                                          Re: C# Performance Richard Allbert Tue Feb 21, 2012 6:37 pm
                                                                                          Re: C# Performance Vincent Diepeveen Sat Feb 18, 2012 10:19 pm
                                                                                          Re: C# Performance Mark Pearce Sun Feb 12, 2012 2:01 pm
                                                                                          Re: C# Performance Richard Allbert Sun Feb 12, 2012 4:40 pm
                                                                                          Re: C# Performance Vincent Diepeveen Sat Feb 18, 2012 10:06 pm
                                                                                          Re: C# Performance Mark Pearce Sun Feb 19, 2012 1:01 pm
                                                                                          Re: C# Performance Vincent Diepeveen Sun Feb 19, 2012 5:25 pm
                                                                                          Re: C# Performance Mark Pearce Sun Feb 19, 2012 7:04 pm
                                                                                          Re: C# Performance Vincent Diepeveen Sun Feb 19, 2012 9:17 pm
                                                                                          Re: C# Performance Mark Pearce Sun Feb 19, 2012 11:33 pm
                                                                                          Re: C# Performance Richard Allbert Sun Feb 19, 2012 9:22 pm
                                                                                          Re: C# Performance Vincent Diepeveen Sun Feb 19, 2012 9:32 pm
                                                                                          Re: C# Performance Vincent Diepeveen Sun Feb 19, 2012 9:37 pm
                                                                                          Re: C# Performance Vincent Diepeveen Sun Feb 19, 2012 10:06 pm
                                                                                          Re: C# Performance Lucas Braesch Wed Feb 08, 2012 10:56 am
                                                                                          Re: C# Performance Mark Pearce Wed Feb 08, 2012 11:30 am
                                                                                          Re: C# Performance Richard Allbert Wed Feb 08, 2012 12:04 pm
                                                                                          Re: C# Performance Tony Soares Tue Feb 07, 2012 3:47 am
                                                                                          Re: C# Performance Richard Allbert Tue Feb 07, 2012 9:55 am
                                          Re: C# Performance Mark Pearce Sat Feb 04, 2012 8:37 pm
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