Incremental Version

About

  • I²DLV is intended as the incremental version of the intelligent grounder I-DLV: as its standard version, I²DLV is an Answer Set Programming (ASP) instantiator that natively supports the ASP-Core-2 standard language.

  • The I²DLV instantiation mechanism allows repeated “shots” in which previous instantiations are reused and updated according to the so-called “overgrounding technique”.

Download

  • You can download a beta release of I²DLV, here.

How to execute

It is possible to use the I²DLV system in different ways:

  • Run the system without any command-line options. The system will wait for user input. The default incremental grounding policy is the one described in the TPLP2019 paper.

./i2dlv

  • Forces output to be printed in textual format (see all the available options below).

./i2dlv -t

  • Run the system enabling simplification and desimplification steps as described in the ICLP2020 submission. The system will wait for user input.

./i2dlv --isd

  • Run the system with an associate XML file containing a set of instructions that has to be executed. The output will be printed in textual format.

./i2dlv -t < file.xml

How to Cite I²DLV

Syntax

Command

XML Command Scripts

  • I²DLV is intended to be executed as a process which is kept alive in memory. Users can communicate with the process by simply piping XML commands specifying the desired tasks. A permanent in-memory instantiation can be created, updated and piped to a given ASP solver.

Currently, the following XML commands are available:

Load Command

  • The tag load can be used to form an XML element that requests to load input programs or data; the admitted attribute is:

  • path a file path pointing to the data to be loaded, in ASP-Core-2 format.

    Example of load tag:

    <load path="./recursion.0.asp"/>

Ground Command

  • The tag ground can be used to form an XML statement that instructs I²DLV to ground/update the current logic program and, possibly, send the current instantiation to a solver; the admitted attributes are:

  • run_mode, which can be set to the following 3 values:

    1. print: the current ground program is updated and the result is printed on stdout (default);

    2. updateonly: the current ground program is updated in memory and no output is provided;

    3. solve: the current ground program is updated in memory and, then, piped to a solver. By default, the ground program is sent to the wasp solver (it is assumed that wasp is reachable in the default user PATH). The solver output will be printed on stdout.

      • solve_with: the default solver and its command-line options can be overriden when this value is specified.

Example of ground tag:

  • I²DLV updates the ground program and prints the result on stdout:

    <ground/>

  • I²DLV produces the ground program without printing the result:

    <ground run_mode="updateonly"/>

  • I²DLV produces the ground and pipes the result to a solver (wasp in this example).

Note

Note that --mode=wasp and --printonlyoptimum are options of the dlv2 system.

<ground run_mode="solve" solve_with="./dlv2 --mode=wasp --printonlyoptimum"/>

Reset Command

  • The tag reset can be used to form an XML element that requests to reset all data loaded so far. No attribute is admitted.

Example of reset tag:

<reset/>

Exit command

  • The tag exit can be used to form an XML element that requests to close the process. No attribute is admitted.

Example of exit tag:

<exit/>

Command-line Options

Grounding Options

  • --isd, --incremental-simpl-desimpl enable simplification and desimplification steps during grounding.

Output Options

  • -t, --textual prints in textual mode (same behaviour of --output=1), instead of the default numeric.

  • --filter filters the specified predicates with the specified arity.

    Example:

    --filter=p1/2,p2/3.

  • --print-rewriting prints in STDERR the rewritten program as preprocessed by IDLV.

Statistics Options

  • --time the system prints the grounding time of each rule.

  • --istats the system displays incremental grounding statistics.

General Options

  • --help the system prints this guide and exit.

  • --stdin the system reads input from standard input (default).

  • --mode set the execution mode:

    • 0 = Console: the user provides commands via standard input.

    • 1 = Server: the user provides commands via a connection over the IP and port numbers at which the system is reachable.

    Note

    By default --mode is set to 0.

  • --port set the port number in server mode (by default, it is set to 4790).

Example

  • A zip archive with a full working example can be downloaded, here. The File included in the zip archive are listed in the following.

  • The test folder containing:

    recursion/recursion.*.asp: ASP files given in input to I2DLV.
disjunction/disjunction.*.asp: ASP files given in input to I-DLV Incremental.
template.xml: it is an XML file containing all the instructions that have to be executed by I2DLV.

  • solver folder containing:

    dlv2: binaries of systems that integrate an ASP solver.

Disjunction

How to execute

./idlv-incremental/i2dlv < test/disjunction/template.xml

Recursion

How to execute

./idlv-incremental/i2dlv < test/recursion/template.xml