A tool to navigate answer-set programs using facets.
Python (tested with python 2.7)
Clingo (tested with clingo 5.2)
Information about Clingo and how to download it is available here.
Releases of python are available here.
In order to run INCA, clingo.(pyd / so) needs to be in the same directory of inca.py.
The tool can be launched using the command
python inca.py -f <asp_program.lp>
List of the tool's commands
Apply a nav. step using an inclusive facet ex: p(y1,y2)
Apply a nav. step using an exclusive facet ex: #not p(y1,y2)
Retract a specific facet ex: #del p(y1,y2)
Show the consequences of removing certain facets ex: #what p(y1,y2)
Calculate all minimal correction sets w.r.t. some facet ex: #how p(y1,y2)
Retract all facets delall
List all applied facets lk
Display active / inactive facets show
Terminate the program exit
The following is an example of the faceted navigation of the graph coloring problem with 3 colors.
Input program
%Every node has exactly one color
{ color(X,C): col(C) } = 1 :- node(X).
%Connected nodes must have different colors
:- edge(X,Y), color(X,C), color(Y,C).
%Nodes
node(1..6).
%Colors
col(r). col(g). col(b).
%Edges
edge(1,(2;6)). edge(2,(1;3;4)). edge(3,(2;4;5)).
edge(4,(2;3;5)). edge(5,(3;4;6)). edge(6,(1;5)).
To apply a navigation step, a facet from the available one must be chosen, in our example we choose the color of node 2 to be green by typing color(2,g).
This selection implies that node 5 must be green as well, therfore the user's confirmation is required. Afterwards three lists would be displayed
Unavailable Facets:
------------------
color(1,g) color(2,b) color(2,r) color(3,g) color(4,g) color(5,b) color(5,r) color(6,g)
not color(5,g) not color(2,g)
Available Facets:
----------------
color(3,b) color(4,b) color(6,r) color(1,r) color(3,r) color(4,r)
color(6,b) color(1,b) not color(3,b) not color(4,b) not color(6,r)
not color(1,r) not color(3,r) not color(4,r) not color(6,b) not color(1,b)
Chosen Facets:
-------------
color(5,g) color(2,g)
After applying color(1,b). and then #not color(3,r)., we reach the end of the navigation because there are no more facets to apply any additional steps.
Computing all minimal correction sets of the current program with respect to #not color(4,r). can be achieved via #how #not color(4,r).
Total number of correction sets = 2
To be able to select not color(4,r) you have to remove
color(2,g)
or
not color(3,r)
Input programs must not have the #show command because it creates a problem in desplaying the correction sets.
Removing multiple facets, as well as the inquiry about the consequences of removing multiple facets is possible; facets must be seperated by "/".