TABDUAL+int : An Improvement of TABDUAL+ by Adding Interned Terms

About TABDUAL+int

TABDUAL+int is an improvement of TABDUAL+ (see https://github.com/harventhy/tabdual-plus) by adding an advance feature tabling which is tabling with interned terms. TABDUAL+int is implemented in XSB Prolog, so you need to install XSB Prolog in your machine. For convenience, you might want to put the path to directory where the XSB command is found in your $PATH environment variable. Otherwise, you have to include the path to directory where you have this implementation into XSB default search paths using predicate library_directory/1.

How to Specify Your Knowledge Base

You can define an input program, i.e. a logic program, as your own knowledge base inside in folder in a file called {filename}.ab. Your input program has to satisfy following properties:

• Abducibles is specified by predicate abds/1 whose argument is a list of abducibles along with its arity. For example abds([a/1, b/2, c/3]).
• To define a rule (including an integrity constraint), please use <- instead of :- to denote if operator. For example, please use H <- X, Y. instead of using H :- X, Y..
• Predicates comprising just fact are written separately between the beginProlog. and endProlog. identifiers.
• Regular Prolog programs (those that will not be transformed) are also written separately between the beginProlog. and endProlog. identifiers. Please use H :- X, Y. instead of using H <- X, Y. when defining regular Prolog programs because these programs will not be transformed but will be rewritten as it is.

With regard to properties mentioned above, your input program must be written in following parts, ordered from top to bottom:

1. beginProlog. and endProlog. identifiers, and also facts and programs that need to be placed between them. This part is unnecessary when no such program in it.
2. Abducibles.
3. Rules.

How TABDUAL+int Works

TABDUAL+int implementation consists of two phases:

1. Program transformation. In transformation phase, your input program will be transformed into its corresponding output program that supports contextual abduction. The output program will be used in the next stage. Before you transform your input program, you can choose what mode of transformation you want to use using predicate switch_mode/1. TABDUAL+int provides four transformation modes, which are no tabling, normal tabling, tabling with answer subsumption, and tabling with interned terms. Those program transformation respectively coded into n, t, s, and i. For example, if you want to using tabling with interned terms mode, you must switch mode using directive switch_mode(i). Notice that in TABDUAL+int, the default mode is normal tabling mode. So, if you skip this step, you will automatically using normal tabling mode for transformation program.
   To transform your input program {filename}.ab, type transform({filename}). and then hit Enter. The output program {filename}_{InitialMode}.pl will be created in out folder. For example, if you want to transform an input program goodgrades.ab using tabling with interned terms mode, you have to type transform(goodgrades), and consequently a file goodgrades_int.pl will be created in out folder. Remember that your input program goodgrades.ab must be placed inside in folder. To avoid errors in the next steps, please always perform this step even though the corresponding output program has been created.
2. Abduction. In abduction phase, you may perform the abduction itself output program that is produced in the previous stage. Practically, you have to load the output program first, only then you can perform abduction by asking queries to the loaded program.

How to Use

1. Open a terminal in the directory where you have this implementation.

2. Invoke XSB by the command:

$ xsb

Notice that this command may vary depends on how XSB is configured in your machine. Make sure you have entered XSB prompt level (indentified by | ?- prompt) before you proceed to the next step.

3. Type [tabdual]. and then hit Enter to load the main program.

4. Type load({filename}). and then hit Enter to load your output program. For example, you have to type load(goodgrades) to load the output program goodgrades_int.pl. Make sure you have transformed the corresponding input program that you want to load, otherwise errors may occur.

5. Now you may ask a query using predicate ask/1 whose argument is the query you want to ask. If you want to retrieve the solution gradually, please use ask/2 whose first argument is the query you want to ask, while the second is the solution to the query, retrieved one by one. If you want to supply abductive contexts, use predicate ask/3 instead, whose second argument is a list of abductive contexts you want to supply, the first and the last arguments remain the same as ask/2. Please do not forget to use parentheses if you are asking multiple goals in the query. Here are some example of usage predicate ask/1, ask/2, and ask/3. These examples will use in/goodgrades.ab as its input program.

   % using ask/1
   ?- ask(getting_good_grades)).
(1) [getting_lucky,healthy]
(2) [have_study_notes]
yes
   

   % using ask/1 with multiple goals
   ?- ask((getting_good_grades,studying_hard)).
(1) [getting_lucky,healthy,have_study_notes]
(2) [have_study_notes]
yes
   

   % using ask/2
   ?- ask(getting_good_grades, O).
O = [getting_lucky,healthy]; % type ';' to retrieve next goals
   O = [have_study_notes];
no
   

   % using ask/3 (with conflicting abductive context)
   ?- ask(q(1), [not a(1)], O).
O = [not have_study_notes,getting_lucky,healthy];
no

More detail

If you want to know more how this program work including the experiment results, you can read our paper in here: http://jiki.cs.ui.ac.id/index.php/jiki/article/view/569/404.

How to cite us

You are free to use and improve the TABDUAL+int, but if you want to publish paper/publication using the TABDUAL+int, please cite this publication:

M. O. Ibrohim and A. Saptawijaya, “Tabling with Interned Terms On Contextual Abduction”, Jurnal Ilmu Komputer dan Informasi, vol. 12(1), pp. 1-11, 2019. (Every paper template may have different citation writting. For LaTex user, you can see citation.bib).

License

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.