Helo everyone,n I can't find what's the problem with my planning here that makes the goal unsolvable. I would like to ask what could be the problem here?
Problem.txt:
start(
at(Monkey, a),
at(Banana, b),
at(Box, c),
height(Monkey, Low),
height(Box, Low),
height(Banana, High),
pushable(Box),
climbable(Box)
)
goal(
have(Monkey, Banana)
)
Domain.txt:
operator go(X,Y)
pre: at(Monkey, X), height(Monkey, Low)
post: at(Monkey, Y), ~at(Monkey, X)
operator push(B,X,Y)
pre: at(Monkey, X), height(Monkey, Low), at(B, X), height(B, Low), pushable(B)
post: at(B, Y), at(Monkey, Y), ~at(B, X), ~at(Monkey, X)
operator climbUp(X,B)
pre: at(Monkey, X), height(Monkey, Low), at(B, X), height(B, Low), climbable(B)
post: on(Monkey, B), ~height(Monkey, Low), height(Monkey, High)
operator grasp(X,B,H)
pre: at(Monkey, X), height(Monkey, H), at(B, X), height(B, H)
post: have(Monkey, B)
The error:
INFO: Expanding graph
INFO: Goals not possible with 1 steps
INFO: Expanding graph
INFO: Goals not possible with 2 steps
INFO: Expanding graph
INFO: Goals not possible with 3 steps
INFO: Expanding graph
INFO: Goals not possible with 4 steps
Exception in thread "main" graphplan.graph.PlanningGraphException: At graph level 8: Goals are not possible and graph has levelled off, plan is not possible.
at graphplan.Graphplan.plan(Graphplan.java:238)
at graphplan.Graphplan.main(Graphplan.java:137)
