Incremental Updating of Objects in INDIGO

This paper shows the incremental updating that is used in the Go playing program Indigo. Due to the size of the board and time constraints, incremental mechanisms are relevant to update data. The evaluation of a position includes the construction of a taxonomy of objects which are linked by a lot dependencies. Therefore, classical incremental approaches use browsing of the taxonomy to udate objects. In Indigo, we use a different approach that use the spatial features of the game of Go. Each object is a "relying object" with a "location" and a "track". The later is the set of intersections on which the object depends. When a move is played somewhere on the board, browsing of dependencies is not necessary and "tracks" are used instead. The objects whose track meets the location of the move are deleted and the other ones are not. This mechanism symplifies the task of the programmer in pushing the incrementality problem into the specification of the track of each class of objects. This mechanism slightly reduces the response time of Indigo by a ratio of 50 on 19x19 boards without modifying the play of the program.