asprilo Encodings

About

This is a collection of encodings for asprilo.

Directory Structure

The encodings are grouped in three root directories wrt. their problem domains:

• ./abc contains encoding for asprilo domains A, B and C

• ./m contains encodings for asprilo domain M

• ./control contains encodings for supplementary features such as task assignment, highway constraints, etc. for all (some) asprilo domains

File Name Convention

We adopt the following name conventions for the encoding files:

• For the base name of encoding files

  • capital letters M, P, P, and D stand for actions move, pickup, putdown, and deliver

  • lower case suffixes -c, -b, and -a indicate the addressed problem domain

  • specifically, this applies to all files matching

    • ./abc/goal-D-{a,b,c}.*
    • ./control/control-{a,b,c,m}.*
    • ./control/assign-{a,bcm}.*
    • etc.

• File extensions *.lp*, *.ilp, *.clp, *.iclp and *.dlp stand for regular, incremental, constraint, incremental constraint logic and difference logic programs, resp.

  • sometimes we need to disambiguate further, e.g. we use capital C in *.Clp and *``*.iClp to indicate that we use constraints for both robot & shelf positions and product quantities

• Omissions of such indicators are treated like wild-cards, i.e., general applicability

• Compatibility of encoding files is achieved by combing those with same (or similar) attributes.

Interface to asprilo I/O Format

• Files with base name prefix input* and output* handle I/O between asprilo and the encodings, e.g.

  ./input.lp
  ./m/output-M.lp
  ./m/output-M.ilp
  ./abc/output-MPPD.ilp
  ./abc/output-MPPD.lp
  ...

• Specifically,

  • input.lp converts asprilo instances to the format used in action theories and
  • output* files convert the resulting plan into the format of asprilo

Action Theory

• Files with base name prefix action* hold action theories, e.g.

  ./m/action-M.lp
  ./m/action-M.ilp
  ./abc/action-MPP.ilp
  ./abc/action-MPP.lp
  ...

• Encoded actions are move, pickup, and put-down.

Goal Conditions

• Files with base name prefix goal* hold goal conditions, e.g.

  ./m/goal-M.ilp
  ./m/goal-M.lp
  ./abc/goal-D-a.lp
  ./abc/goal-D-a.ilp
  ./abc/goal-D-b.lp
  ./abc/goal-D-b.ilp
  ...

• Except for asprilo domain M, they define what constitutes a delivery action indicated by capital letter D in the file names.

• Goal conditions depend on the asprilo domain and, hence, use in directory .abc/ base name suffixes *-a, *-b *-c for distinction

Product Quantities

• Files with base name prefix quantities* deal with amounts of products, e.g

  ./abc/quantities.clp
  ./abc/quantities.iclp
  ./abc/quantities.ilp
  ./abc/quantities.lp

• Goal condition encodings for domain A include quantity encodings fitting to their logic program type (*.lp, *.ilp, .clp, etc.)

Strategies

• Files with base name prefix strategy specify strategies, e.g.

  ./abc/strategy-MPP.ilp
  ./abc/strategy-MPP.lp

• Some strategies may not work with all layouts!

• Experimental feature!

Highways

• Files with base name prefix highways specify conditions for highway gird nodes, e.g.

  ./control/highways.lp
  ./control/highways.ilp
  ./control/highways.clp
  ./control/highways.iclp

Optimization

• Files with base name prefix optimization* specify objective functions, e.g.

  ./abc/optimization.lp
  ./abc/optimization.ilp

• Experimental feature!

Heuristics

• Files with base name prefix heuristic* specifying heuristics with clingo's #heuristic directive, e.g.

  ./control/heuristic.lp
  ./control/heuristic.ilp

• Experimental feature!

Encoding Shorthands

• Files with base name prefix encoding* provide shorthands to call matching action theory and goal encodings, e.g.

  ./abc/encoding-a.lp
  ./abc/encoding-a.ilp
  ./abc/encoding-b.lp
  ./abc/encoding-b.ilp
  ./abc/encoding-c.lp
  ./abc/encoding-c.ilp
  ./m/encoding.lp
  ./m/encoding.ilp
  ...

• This helps to shorten some calls (e.g. for benchmarking) and illustrate which encoding files fit together

Invocation Examples

• Some warehouse layouts merged with orders can be found in the directory ./examples Many of them contain (uncommented) calls in their header, e.g.

  clingo abc/{action-MPP.lp,strategy-MPP.lp,goal-D-c.lp,output-MPPD.lp} \
         examples/x4_y4_n16_r2_s3_ps1_pr2_u4_o2_N1.lp -c horizon=8

• There are also auxiliary bash scripts that for a clean output of facts:

  • ./clingo1facts to print only facts in one line
  • ./ clingo2facts to additionally print each fact in a new line (--out-ifs='\n')

asprilo Visualization

You can display your instance and plan execution in the asprilo's visualizer on the command-line by running

clingo $OPTS $ENCODINGS --outf=0 -V0 --out-atomf=%s. | \
head -n 1 | \
$VIZUALIZER

where

• $ENCODINGS holds your list of encoding file paths
• $OPTS holds your clingo options
• clingo options--outf=0 -V0 --out-atomf=%s. formats the output answer set in adherence to asprilo's input format
• UNIX command head -n1 strips off the trailing (UN)SATISFIABLE
• $VIZUALIZER holds the path to the asprilo visualizer script

For example

clingo abc/{action-MPP.lp,goal-D-c.lp} examples/x4_y4_n16_r2_s3_ps1_pr2_u4_o2_N1.lp -c horizon=8
output-MPPD.lp --outf=0 -V0 --out-atomf=%s. | head -n1 | $VISUALIZER