PlanPilot: Navigating the Plan Space with Facets

PlanPilot is a tool that allows the user to interactively navigate on the plan space of a planning problem. For example, the user can interactively (de)activate facets of the plans, in order to understand the plan space better.

Right now, PlanPilot supports classical planning problems described in PDDL or SAS+.

Build

The easiest way is to build an Apptainer container as follows:

apptainer build planpilot.sif Apptainer.planpilot

Usage

Basic usage:

./planpilot.sif -i /path/to/instance.pddl --horizon HORIZON

where HORIZON is a positive number.

Beluga Usage

For example, consider the Beluga Challenge with a horizon of 17 and a single fixed action at time step 12. One can enumerate or reason about the importance of the PlanPilot as follows:

./planpilot.sif -i benchmarks/beluga-exp-solvable/problem_3_s45_j3_r2_oc44_f3.pddl --horizon 17 --script scripts/list-facets.fasb --add-constraints ":- not occurs(action(("pick-up-rack","jig0002","factory_trailer_1","rack00","fside","bside","n25","n05","n30")), 12)."

./planpilot.sif -i benchmarks/beluga-exp-solvable/problem_3_s45_j3_r2_oc44_f3.pddl --horizon 17 --script scripts/facet-reason.fasb --add-constraints ":- not occurs(action(("pick-up-rack","jig0002","factory_trailer_1","rack00","fside","bside","n25","n05","n30")), 12)."

To start interactive mode, use the following command: Then, navigation in the plans space is possible with the fasb commands listed below.

./planpilot.sif -i benchmarks/beluga-exp-solvable/problem_46_s89_j3_r2_oc32_f3.pddl --horizon 17

Other arguments:

• -h, --help show this help message and exit
• -i INSTANCE, --instance INSTANCE The path to the PDDL/SAS instance file.
• -d DOMAIN, --domain DOMAIN (Optional) The path to the PDDL domain file. If none is provided, the system will try to automatically deduce it from the instance filename.
• --partial-plan PARTIAL_PLAN The path to the file containing partial plan.
• --add-constraints ADD_CONSTRAINTS String containing additional constraints.
• --add-constraints-file ADD_CONSTRAINTS_FILE The path to the file containing additional constraints.
• --dry If true, facets will not be computed at startup.
• --horizon HORIZON Horizon used by clingo.
• --lp-name LP_NAME Name of intermediate logic program (lp) file.
• --encoding {exact,bounded} Type of ASP encoding.
• --abstract-time-steps If true, it only reports that actions occur some time during the plans, but without specifying when.
• --script SCRIPT The path to the fasb script; for non-interactive mode - requires fasb built in interpreter configuration.
• --dump-output dump the output of tools.
• --cleanup Clean all LP files in the folder after execution.

The program first encodes the planning problem as an answer set program using plasp (Gebser et al. 2011; Dimopoulos et al. 2019; link to repo. It then executes fasb (Fichte et al. AAAI 2022; link to repo) using its interactive mode. The original README.md and LICENSE of fasb can be found in the directory bin/fasb-x86_64-unknown-linux-gnu.

fasb Commands

Below is a list of the "essential" commands of fasb. We also comment on how they relate to the planning context:

• ! n: list n different answer sets (plans, in our context). If n is not given, all answer sets will be listed
• ?: display all facets
• #!: count the number of answer sets (plans)
• #?: count the number of atomic facets (meaningful operators)
• #!!: query for each facet how much its activation decreases the number of answer sets, and the remaining number of answer sets
• #??: query for each facet how much its activation decreases the number of facets, and the remaining number of facets
• + FACET: activate the facet FACET. Use the same string for FACET as listed when using the command #??.
• - FACET: deactivate the facet FACET. Use the same string for FACET as listed when using the command #??
• :q: quit fasb

Fast Downward Translator

We utilize for grounding the Fast Downward translator (files).