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Fast Downward 22.06

Fast Downward 22.06 was released on June 16, 2022.

Highlights:

• We fixed a bug in the translator component that could lead to incorrect behavior in tasks where predicates are mentioned in the goal that are not modified by any actions.
• Various speed improvements to landmark factories. This is part of a larger ongoing clean-up of the landmark code.
• More informative output, and more control over the output. The driver now prints the total runtime of all components. For many planner components, including all heuristics, the verbosity level can now be configured individually.

The Apptainer and Docker distributions of the planner include LP support using the SoPlex solver. Thank you to ZIB for their solver and for giving permission to include it in the release. SoPlex is licensed under the ZIB Academic License.

Downloads

• source tarball: fast-downward-22.06.tar.gz

• Apptainer (formerly known as Singularity) image: fast-downward.sif

• Docker container: aibasel/downward:22.06 on Docker Hub

• Vagrantfile: Vagrantfile for Fast Downward 22.06

For Apptainer, Docker and Vagrant, see QuickStart for instructions on how to run the planner. That page explains how to run the latest release of Fast Downward, so you have to amend the instructions if you want to run an older release.

For the tarball, if you have satisfied all dependencies, the following should build and run the planner with configuration alias lama-first on PDDL files /path/to/domain.pddl and /path/to/problem.pddl on a Linux or macOS system:

tar -xvzf fast-downward-22.06.tar.gz
cd fast-downward-22.06
./build.py
./fast-downward.py --alias lama-first /path/to/domain.pddl /path/to/problem.pddl

For dependencies and more advanced information (including Windows builds), see ObtainingAndRunningFastDownward.

Limitations

For licensing reasons, the binary distributions of Fast Downward have limited support for commercial LP solvers (CPLEX and Gurobi). The Docker and Apptainer distributions only support SoPlex. The Vagrant version supports SoPlex and/or CPLEX if they are available at provisioning time. See QuickStart for more information.

Referencing Fast Downward 22.06

If you use this version of Fast Downward in a scientific publication, we encourage you to mention the version number, as in "We ran experiments with Fast Downward 22.06." The canonical reference for citing Fast Downward is the following journal paper:

@Article{helmert-jair2006,
  author =  "Malte Helmert",
  title =   "The {Fast} {Downward} Planning System",
  journal = "Journal of Artificial Intelligence Research",
  year =    "2006",
  volume =  "26",
  pages =   "191--246"
}

Changes in Fast Downward 22.06

• translator: Fix a bug where the translator would not check goal conditions on predicates that are not modified by actions.
  https://issues.fast-downward.org/issue1055

• driver: Print overall planner resource limits and overall planner runtime on Linux and macOS systems.
  https://issues.fast-downward.org/issue1056

• logging: verbosity option for all evaluators
  https://issues.fast-downward.org/issue921
  All evaluators and heuristics now have their own configurable logger and no longer use g_log. These loggers have a verbosity option, which allows choosing between silent, normal, verbose and debug for all instances of evaluators created on the command line.

• landmarks: Speed up landmark generation time by 10-20% for lm_rhw, lm_zg, and lm_exhaust by avoiding unnecessary computations in the landmark exploration.
  https://issues.fast-downward.org/issue1044

• landmarks: Speed up landmark generation time by 5-15% for lm_rhw, lm_zg, and lm_exhaust` by computing reachability in the landmark exploration as boolean information instead of (unused) integer cost/level information.
  https://issues.fast-downward.org/issue1045

• landmarks: Improve landmark dead-end detection so that relevant static information is only computed once, instead of at every state evaluation.
  https://issues.fast-downward.org/issue1049

• infrastructure: Upgrade GitHub Actions to Windows Server 2019 (Visual Studio Enterprise 2019) and Windows Server 2022 (Visual Studio Enterprise 2022). Remove Windows Server 2016, because GitHub Actions no longer support it.
  https://issues.fast-downward.org/issue1054

• infrastructure: Run GitHub Actions only for the following branches: main, issue*, release-*.
  https://issues.fast-downward.org/issue1027