[rules-users] How to write a rule which only fires for a closest value?

HI, i have a problem using tileworld model, i'm supposed to write a rule which will cause the agents to choose the tile in the agent's range which is closest to the agent. so a rough idea is when agent: Agent(x1:x, y1:y, r:range) tile1: Tile(<tile's x to be between (x1+r) and (x1-r)> && <tile's y to be between (y1+r and y1-r)>) tile2: not Tile( < which is closer than the tile1 to agent> ) desperately need help, alternatives tried:: i tried to use a query to return a list of tiles which is within the agent's range then compared which one is closer and other similar implementation, but this too slow for my simulation... I need one single good rule or efficient way of implementing the above rule then i tried to do multiple constraints too, say x (> 30 && < 40) is ok but x (> ($x-$r) && < ($x+$r)) gives errors ,due to extra parenthesis? i dunno.. any workarounds? Thanks! -- View this message in context: http://www.nabble.com/How-to-write-a-rule-which-only-fires-for-a-closest-... Sent from the drools - user mailing list archive at Nabble.com.