Description
Wumpus&World
Due&October&27th
Will&be&discussed&in&class&on&the&25th
Your!assignment!is!to!build!a!knowledge3based!agent!who!can!solve!problems!in!the!
Wumpus!World.
You!will!have!access!to!code!that!builds!and!manages!a!world!for!you.!!It!will!take!
actions!as!input!and!return!the!state!of!the!world!that!results!from!those!actions.!
In!general,!you!can!take!actions!that!change!the!direction!you!are!facing,!move!
forward!and!either!pick!things!up!or!shoot!an!arrow.!Once!you!have!scored!some!
points!and!returned!to!your!home,!you!can!also!leave!the!game.
Moves&that&change&your&orientation:&&Up,!Down,!Left,!Right
The move&that&changes&your&position:&Step
The&move&that&allows&you&to&exit&the&board:&Exit
Actions&that&change&the&world&aside&from&your&position:&PickUp,&Shoot
You!invoke!these!actions!by!calling!the!function!take_action (in!the!file!
updatewumpus.py)!that!takes!the!name!of!a!world!(more!on!that!shortly)!and!a!
move.!!It!returns!a!list!of!strings!that!describes!the!current!perceptions!that!are!
available!to!you:
(smell,!air,!glitter,!bump,!scream,!location,!orientation,!status,!score)
The!possible!values!of!these!perceptions!are:
Smell 3 clean|nasty
Air 3 calm|breeze
Glitter 3 bare|glitter
Bump 3 no_bump|bump
Scream 3 quiet|scream
Location 3 unique!identifier!for!current!square
Orientation 3 the!direction!you!are!facing
Status 3 living|dead|won
Score 3 current!score
Before!you!start!the!game,!you!need!to!initialize!a!“world.”!!You!do!this!by!calling!
intialize_world,!a!function!that!has!no!arguments.!!This!returns!the!name!of!a!new!
world!that!you!need!to!use!when!calling!take_action.!!This!function!builds!a!folder!
(“WumpusWorldDataFolder “)!where!the!world!data will!be!saved.!!It!does!not!
delete!any!of!the!worlds!it!builds!(but!they!are!tiny)!so!you!might!want!to!clear!this!
folder!occasionally.!!It!didn’t!want!to!include!any!code!that!removes!files/folders.
You!will!need!to!download!updatewumpus.py!and!include!it!in!your!agent!file:
include!updatewumpus
You!will!need!to!initialize!a!world!before!you!start!to!play!and!hold!onto!the!name!of!
that!world:
world_name =!updatewumpus.intialize_world()
At!run!time,!you!will!get!a!message!like!this:
Initializing!your!new!Wumpus!world!
Your!new!world!is!called:!Wumpus3231
You!are!starting!in!Cell!11,!looking!to!the!Right.
You!are!starting!with!0!points,!1!arrow(s).
You!are!alive.
Now!you!can!take!actions!by!!calling!take_action:
updatewumpus.take_action(name,!”Up”)
or!
updatewumpus.take_action(name,!”Step”)
take_action will return!a!precept!list!every!time!it!is!called!that!looks!like!this:
[‘clean’,!’calm’,!’bare’,!’no_bump’,!’quiet’,!’Cell!11′,!’Up’,!’living’,!0]
or
[‘nasty’,!’calm’,!’bare’,!’no_bump’,!’quiet’,!’Cell!12′,!’Up’,!’living’,!0]
It!will!also!provide!you!with!messaging!so!you!can!track!the!game:
*********************************
Turing!to!face!Up
Perception!=!(clean,!calm,!bare,!no_bump,!quiet,!Cell!11,!Up,!living,!0)
*********************************
Taking!a!step
Moving!to!Cell!12
There!is!a!nasty!smell!in!here
Perception!=!(nasty,!calm,!bare,!no_bump,!quiet,!Cell!12,!Up,!living,!0)
You!can!also!get!the!names!of!adjacent!cells!by!calling!look_ahead.!It!takes!the!name!
of!the!world and!returns!a!list!of!the!cells!that!are!next!to!you.
updatewumpus.lookahead(world_name)
returns
[‘Cell!13′,!’Cell!11′,!‘Cell!22’]
The!idea!behind!this!is!you!can!use!this!information!start!to!ASSERT facts!about!the!
world!as!you!play.!
Once!you!die,!the!world!will no!long!update!and!your!status!will!change!to!“dead”!in!
you!perception!list.!Also:
You!cannot!PickUp!the!gold!if!there!is!no!gold.
You!only!have!one!arrow!to!Shoot.
You!can!only!Exit!if!you!have!scored!some!points!and!are!at!your!home.
Once!you!have!killed!the!Wumpus,!you!can!enter!its!room without!dying.
The assignment.
You!goal!is!to!build!an!agent!that!is!able!to!move!safely!through!its!world,!collect!
gold,!kill!the!Wumpus,!and!then!exit.
Given!that!you!are!starting!with!no!knowledge!of!the!world,!you!are!going!to!have!to!
have!your!agent!figure!things!out!as!it!goes!along.!!You!will!need to!build!up!a!set!of!
inference!rules!that!will!fire!as!new!facts!are!known.
For!example,!if!you!are!on!a!square!with!no!breeze,!then!you!can!add!this!fact!to!the!
data,!add!facts!about!what!squares!are!adjacent!to!it,!and!then!infer!that!those!
squares!have!solid!floors.
That!is,!ASSERT:
Calm(Cell!11)
Adjacent(Cell!11,!Cell!12)
Adjacent((Cell!11,!Cell!21)
And!then!use!a!rule!like:
Calm(?x)!V!Adjacent(?x!?y)!=>!Solid(?y)
to!make!the!right!inferences.
You!will!need!to!use!your!knowledge!base!to!figure!out!which squares!have!solid!
floors!and!no!Wumpus,!are!safe!(solid!floor!and!no!Wumpus),!and!where!the!
Wumpus!is!so!you!can!shoot!it.!!AS!you!wander,!you!should!probably!also!be!
thinking!about!how!to!save!information!about!what!constitutes!as!good!path!back!to!
the!start.
The!approach!we!are!taking!is!to!use!a!knowledge!base!as!the!repository!of!what!is!
true!(i.e., known!by!the!system)!and!another!system!(a!planner)!to!make!decisions!
based!on!what!it!knows!and!what!it!wants!to!accomplish.
The!knowledge!side!of!things!requires!a!repository!of!facts!and!a!repository!of!rules.!!
As!we!discussed,!as!new!rules!are!added,!we!check!to!see!if!they!allow!you!to!infer!
anything!given!the!fact!that!you!know.!!Likewise,!as!you!add!new!facts,!you!need!to!
check!to!see!if!any!rules!can!be!fired.
In!order!to!access!this!information!you!will!need!to!be!able!to:!
ASSERT facts!and!rules.!(This!room!has!no!breeze.)
ASK if!things!you!care!about!are!true? (Is!this!room!I!want!to!go!into!Safe?)
Your!agent!should!have!specific!goals!it!is!trying!to!accomplish!(pick!up!the!gold)!
and!know!that!it!will!have!to!take!actions!in!order!to!set!up!the!conditions!that!
makes!this!possible!(stand!in!the!same!room!as!the!gold).
The!challenge!is!that!you!will!need!to!be!able!to!not!just!add!facts but!also!draw!
inferences!from!them.!!Your!inference!rules!will!need to!have!variables!so!that!they!
are!general.!!You!will!need!to!be!able!to!MATCH facts!against!patterns!in!your!
inference!rules.!And!when!you!draw!an!inference,!you!will!need!to!INSTANTIATE
the!result!and!thus!create!a!new!fact!with!all!of!the!variables!replaced!with!the!
elements!from!the!fact!that!was!matched!against!it.
And!you!will!need!to!be!able!to!do!the!same!sort!of!matching for!ASK so!you!can!look!
for!the!answers!to!general queries.
There!is!a!very!simple!implementation!of!MATCH and!INSTANTIATE in!the!file!
FOPC.py.!!
On!Tuesday,!we!will!discuss!this!in!class!and!you!will!get!the!second!piece!of!this!
assignment!that!will!be!a!somewhat!expanded!Wumpus!world!in!which!you!will!
need!to!kill!the!Wumpus!in!order!to!get!to!your!goal.
Deliverables
You!will!be!handing in!your!code!and!the!trace!generated!by!the!world!systems!that!
results!when!you!run!it.
