I am new to PDDL and I'm trying to do a robot cleaner problem but I don't understand why I'm getting this.
reading input... [t=0s] Simplifying transitions... done! done reading input! [t=0s] building causal graph...done! [t=0s] packing state variables...done! [t=0s] Variables: 1 Facts: 2 Bytes per state: 4 done initalizing global data [t=0s] Conducting best first search with reopening closed nodes, (real) bound = 2147483647 Initializing FF heuristic... Initializing additive heuristic... Simplifying 0 unary operators... done! [0 unary operators] Initial state is a dead end. Completely explored state space -- no solution! Actual search time: 0s [t=0s] Expanded 0 state(s). Reopened 0 state(s). Evaluated 1 state(s). Evaluations: 1 Generated 0 state(s). Dead ends: 0 state(s). Number of registered states: 1 Search time: 0s Total time: 0s Search stopped without finding a solution. Peak memory: 2936 KB
(define (domain floor-tile)
(:requirements :typing)
;; We have two types: robots and the tiles, both are objects
(:types robot tile - object)
;; define all the predicates as they are used in the probem files
(:predicates
;; described what tile a robot is at
(robot-at ?r - robot ?x - tile)
;; indicates that tile ?x is above tile ?y
(up ?x - tile ?y - tile)
;; indicates that tile ?x is below tile ?y
(down ?x - tile ?y - tile)
;; indicates that tile ?x is right of tile ?y
(right ?x - tile ?y - tile)
;; indicates that tile ?x is left of tile ?y
(left ?x - tile ?y - tile)
;; indicates that a tile is clear (robot can move there)
(clear ?x - tile)
;; indicates that a tile is cleaned
(cleaned ?x - tile)
)
(:action clear
:parameters (?r - robot?x - tile ?y - tile)
:precondition (and (robot-at ?r ?x) (clear ?x))
:effect (when (cleaned ?x) (not(clear ?x)))
)
(:action clean-up
:parameters (?r - robot ?x - tile ?y - tile)
:precondition (and (up ?y ?x) (robot-at ?r ?x) (clear ?y))
:effect (and (robot-at ?r ?y) (not(robot-at ?r ?x)))
)
(:action clean-down
:parameters (?r - robot?x - tile ?y - tile)
:precondition (and (down ?y ?x) (robot-at ?r ?x) (clear ?y))
:effect (and (robot-at ?r ?y) (not(robot-at ?r ?x)))
)
(:action up
:parameters (?r - robot?x - tile ?y - tile)
:precondition (and (up ?y ?x) (robot-at ?r ?x) (clear ?y))
:effect (and (robot-at ?r ?y) (not(robot-at ?r ?x)))
)
(:action down
:parameters (?r - robot?x - tile ?y - tile)
:precondition (and (down ?y ?x) (robot-at ?r ?x)(clear ?y))
:effect (and (robot-at ?r ?y) (not(robot-at ?r ?x)))
)
(:action right
:parameters (?r - robot?x - tile ?y - tile)
:precondition (and (right ?y ?x) (robot-at ?r ?x) (clear ?y))
:effect (and (robot-at ?r ?y) (not(robot-at ?r ?x)))
)
(:action left
:parameters (?r - robot?x - tile ?y - tile)
:precondition (and (left ?y ?x) (robot-at ?r ?x) (clear ?y))
:effect (and (robot-at ?r ?y ) (not(robot-at ?r ?x)))
)
)
Problem:
(define (problem prob001)
(:domain floor-tile)
(:objects tile_0-1 tile_0-2
tile_1-1 tile_1-2
tile_2-1 tile_2-2 - tile
robot1 - robot
)
(:init
(robot-at robot1 tile_1-1)
(clear tile_0-1)
(clear tile_0-2)
(clear tile_1-2)
(clear tile_2-1)
(clear tile_2-2)
(up tile_1-1 tile_0-1)
(up tile_1-2 tile_0-2)
(up tile_2-1 tile_1-1)
(up tile_2-2 tile_1-2)
(down tile_0-1 tile_1-1)
(down tile_0-2 tile_1-2)
(down tile_1-1 tile_2-1)
(down tile_1-2 tile_2-2)
(right tile_0-2 tile_0-1)
(right tile_1-2 tile_1-1)
(right tile_2-2 tile_2-1)
(left tile_0-1 tile_0-2)
(left tile_1-1 tile_1-2)
(left tile_2-1 tile_2-2)
)
(:goal (and
(cleaned tile_0-1)
(cleaned tile_0-2)
(cleaned tile_1-1)
(cleaned tile_2-2)
))
)
The problem cannot be solved, as there is no way a tile could ever be cleaned.
If you look at the effects of the actions, none of them results in a cleaned tile. So the goal is unachievable. I assume you got the clear and clean predicates confused?