Task
The task in this programming assignment is to design appropriate descriptions of facts, actions, and goals, using the STRIPS language, for two planning problems: the Tower of Hanoi problem, and the 7-puzzle problem (a variation of the 8-puzzle problem where two squares are clear instead of one). You will use your descriptions as inputs to a Graphplan implementation. If your descriptions are correct, Graphplan will produce appropriate plans.
Compiling and Running the Software
The Graphplan software can be downloaded from graphplan.zip. See the README file in that package for additional information. To compile the software on omega, unzip the directory, and, from that directory, type
make graphplan
Once the program compiles, it can be invoked from the commandline as follows:
graphplan -o [operators_file] -f [facts_file]
For example:
graphplan -o block_ops.txt -f block_facts3.txt
- Argument operators_file specifies the location of a text file containing definitions of actions. For example, see block_ops.txt for definitions of actions appropriate for the blocks world.
- Argument facts_file specifies the location of a text file containing definitions of facts about the environment, including objects (and types for those objects), general predicates that are always true, initial state description, and goal description. For example, see block_facts2.txt, block_facts3.txt, and block_facts4.txt for example fact descriptions for the blocks world.
Once you start running the software, it will ask you three questions. Just hit enter for each question, so as to use the default settings. If your descriptions of actions and facts are correct, the program will print out a plan achieving the stated goal.
Note that the preconds in each fact file will contain both statements that are always true in that domain (i.e., in the Tower of Hanoi domain or the 7-puzzle domain), and statements that simply describe the initial state for that specific planning problem. In addition to the facts files for the specific planning problems you are given, you will have to create a separate text file that includes all the statements that must be present in ANY facts file for that domain.
Tower of Hanoi Description
A description of the Tower of Hanoi domain can be found at Wikipedia. In all problems that your program will be tested with there will be five discs (called disk1, disk2, disk3, disk4, disk5) and three pegs (called A, B, C). In all your facts files you will have to include both a common part (defining objects and relations among objects) and a plan-specific part (describing the initial state and goal for each plan). Note that some of the five disks may not appear in some of the planning problems.
The three planning problems you have to solve are:
Problem 1
initial state:
(on disk1 disk2)
(on disk2 A)
(clear disk1)
(clear B)
(clear C)
goal:
(on disk1 B)
Problem 2
initial state:
(on disk1 disk2)
(on disk2 disk3)
(on disk3 A)
(clear disk1)
(clear B)
(clear C)
goal:
(on disk1 disk2)
(on disk2 disk3)
(on disk3 B)
Problem 3
initial state:
(on disk1 disk2)
(on disk2 disk3)
(on disk3 disk4)
(on disk4 disk5)
(on disk5 C)
(clear disk1)
(clear A)
(clear B)
goal:
(on disk1 disk2)
(on disk2 disk3)
(on disk3 disk4)
(on disk4 disk5)
(on disk5 A)
7-puzzle Description
7-puzzle is like 8-puzzle, except that there are only pieces numbered from 1 to 7 (not from 1 to 8), and there are two clear squares on the board. At any move, we can move a numbered piece to an adjacent clear square.
The three planning problems you have to solve are (X indicates a clear square):
Problem 1
initial state:
123
456
7XX
goal:
123
X56
4X7
Problem 2
initial state:
123
456
7XX
goal:
XX1
234
567
Problem 3
initial state:
XX7
654
321
goal:
123
456
7XX
Interim report
The interim report is once again mandatory. The interim report should be submitted via e-mail to the instructor and the TA, and should contain the following:
- On subject line: "CSE 4308/5360 - Programming Assignment 4 - Interim report".
- On body of message: Your name and UTA ID (all 10 digits, no spaces).
- On body of message, or as an attachment (in text, Word, PDF, or OpenOffice format): a description (as brief or long as you want) of what you have done so far for the assignment, and any difficulties/bottlenecks you may have reached (in case you encounter such difficulties, it is highly recommended to contact the instructor and/or TA for help).
For purposes of grading, it is absolutely fine if your interim report simply states that you have done nothing so far (you still get the 10 points allocated for the interim report, AS LONG AS YOU SUBMIT THE REPORT ON TIME). At the same time, starting early and identifying potential bottlenecks by the deadline for the interim report is probably a good strategy for doing well in this assignment.
Grading
The assignment will be graded out of 100 points. 50 points will correspond to your solutions for the Tower of Hanoi world, and 50 points will correspond to your solutions for the 7-puzzle problem. Specifically, the point allocation is:
- 10 points: submitting the interim report on time.
- 60 points: defining facts and actions correctly. The language that you define (i.e., the actions, objects, and general statements that are always true) should be sufficient not only for the specific plans that you are required to construct, but also for any other planning problems that we can define in the Tower of Hanoi domain or the 7-puzzle domain. As part of grading, we will also test your solutions on planning problems that we will make up.
- 5 points: solving any one of the six planning problems you are given (three for the Tower of Hanoi domain, three for the 7-puzzle domain). If you solve al 6 correctly, you get 30 points.
How to submit
Submissions should be made using Blackboard.
Submit a ZIPPED directory called programming4.zip (no other
forms of compression accepted, contact the instructor or TA if you do not know how to produce a ZIP file) that contains the entire Graphplan directory, including code, binaries (that work on omega), and text files. The submission should also contain a file called
readme.txt,
which should specify precisely:
- Name and UTA ID of the student.
- Location of the action files for each domain.
- Location of a file containing object descriptions and statements that are always true in each domain.
- Command lines for how to run Graphplan for each of the six planning problems that you have to solve.
Insufficient or unclear instructions will be penalized by up to 20 points.
Code that does not run on omega machines gets AT MOST half credit (50 points).
Submission checklist
- DID YOU INCLUDE files defining actions for each domain?
- DID YOU INCLUDE files containing object descriptions and statements that are always true in each domain?
- DID YOU INCLUDE a file containing the appropriate fact definitions for each of the six planning problems?
- Is the code running on omega?
- Is the submitted zipped file called programming4.zip?