Re: Incremental Data Structures

[David Fotland <fotland@xxxxxxxxxxxxx>]

Generally I undo the changes to the data structures.  In some cases
I revert back to the old structures.  For example if a move
connect two strings into one, I create a new string structure for
the new one.  The old ones are still around, so it is easy to
revert, without a copy.

David

At 02:38 PM 8/14/98 -0700, Philipp Garcia wrote:
>
>I have a question for those that have written go-playing programs that
>use incremental updates to maintain data structure like string-lists,
>liberties lists, etc... When you take-back a move, do you "undo" the
>modifications to the data structures OR do you revert back to a copy of
>the data structure before the move that you are taking back was placed?
>If you "undo" the modifications, how do you store "undo" information. Is
>it log based similar to how modern databases work? Or does logic direct
>the "undo"? If you revert back to a copy, do you really save enough CPU
>cycles to even justify using incremental structures rather than a full
>re-computation?
>
>
>