Wumpus World
by John Escobar
The Wumpus world is a grid of squares surrounded by walls, where each
square can contain agents and objects. The agent (you) always starts in the
lower left corner, a square that will be labeled [1,1]. The agent's
task is to find the gold, return to [1,1] and climb out of the cave.
To specify the agent's task, we specify its percepts, actions, and
goals. In the Wumpus World, these are as follows:
- In the square containing the wumpus and in the directly (not diagonally)
adjacent square the agent will perceive a stench
- In the squares directly adjacent to a pit, the agent will perceive
a breeze.
- In the square where the gold is, the agent will perceive a
glitter.
- When an agent walks into a wall, it will perceive a bump.
- When the wumpus is killed, it gives out a woeful scream that can
be perceived anywhere in the cave.
- There are actions to go right, left, up, and down. In addition,
the action Grab can be used to pick up the gold, if it is in the same
square as the agent. The action Shoot can be used to fire an
arrow in a straight line in the direction the agent is facing. The
arrow continues until it either hits and kills the wumpus or hits the
wall. The agent only has one arrow, so only the first Shoot
action has any effect. Finally the action Climb is used to
leave the cave; it is effective only when the agent is in the start
square.
- The agent dies a miserable death if it enters a square containing
a pit or a live wumpus. It is safe (but smelly) to enter a square
with a dead wumpus.
- The agent's goal is to find the gold and bring it back to the
start as quickly as possible, without getting killed. To be precise,
100 points are awarded for climbing out of the cave while carrying the
gold, but there is a 1-point penalty for each action taken, and a
1000-point penalty for getting killed.
- The locations of the gold and the wumpus are chosen randomly.
- Each square other than the start can be a pit, with a probability
of 0.2.
In most environments there is a way for the agent to safely retrieve
the gold. In some environments, the agent must choose between going
home empty-handed or taking a chance that could lead to death or to
the gold. And in about 21% of the environments (the ones where the
gold is in a pit or surrounded by pits), there is no way the agent can
get a positive score. Sometimes life is just unfair.
Created by John Escobar