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Usage

Before running Fast Downward, you must build it using the build.py script.

To run Fast Downward, use the fast-downward.py driver script. At minimum, you need to specify the PDDL input files and search options. The driver script has many options to do things like running portfolios, running only the translation component of the planner, using a non-standard build, running a plan validator and various other things. To see the complete list of options, run

./fast-downward.py --help

If you want to run any of the planners based on Fast Downward that participated in IPC 2011, please also check IpcPlanners.

Different builds

Different builds of Fast Downward (e.g. 32-bit vs. 64-bit, release vs. debug) are placed in different directories by the build script. Hence, several builds can coexist and fast-downward.py must be told which build to use. By default, the release32 build is used, which is also the default build produced by build.py. To use a different build, pass --build=<name> to the driver script. The parameter --debug is an alias for --build=debug32 --validate.

Note on IDE projects (Visual Studio, XCode): You can use the CMake build system to generate a project for you favourite IDE. These projects are what CMake calls "multi-config generators", i.e., they are created without fixing the build configuration. At build time, the IDE decides whether to do a debug or release build and creates subdirectories in the output folder. Use the full path to the binaries as the value of --build (e.g., --build=path/to/visual/studio/project/bin/Debug/).

Exit codes

The driver exits with 0 if no errors are encountered. Otherwise, it returns the exit code of the first component that failed. The translator exits with the following codes:

The search component and the portfolios can produce the exit codes listed below. In addition to the numbers we list the names of the exit codes as they are defined in src/search/utilities.h and driver/portfolio_runner.py.

Examples

A* search

   1 # landmark-cut heuristic
   2  ./fast-downward.py domain.pddl task.pddl --search "astar(lmcut())"
   3 
   4 # iPDB heuristic with default settings
   5  ./fast-downward.py domain.pddl task.pddl --search "astar(ipdb())"
   6 
   7 # blind heuristic
   8  ./fast-downward.py domain.pddl task.pddl --search "astar(blind())"

Lazy greedy best-first search with preferred operators and the queue alternation method

   1 ## using FF heuristic and context-enhanced additive heuristic (previously: "fFyY")
   2  ./fast-downward.py domain.pddl task.pddl \
   3     --heuristic "hff=ff()" --heuristic "hcea=cea()" \
   4     --search "lazy_greedy([hff, hcea], preferred=[hff, hcea])" \
   5            
   6 
   7 ## using FF heuristic (previously: "fF")
   8  ./fast-downward.py domain.pddl task.pddl \
   9     --heuristic "hff=ff()" \
  10     --search "lazy_greedy([hff], preferred=[hff])" \
  11            
  12 
  13 ## using context-enhanced additive heuristic (previously: "yY")
  14  ./fast-downward.py domain.pddl task.pddl \
  15     --heuristic "hcea=cea()" \
  16     --search "lazy_greedy([hcea], preferred=[hcea])" \
  17 

LAMA 2011

 ./fast-downward.py --alias seq-sat-lama-2011 domain.pddl task.pddl

runs the "LAMA 2011 configuration" of the planner. (Note that this is not really the same as "LAMA 2011" as it participated at IPC 2011 because there have been bug fixes and other changes to the planner since 2011. See IpcPlanners for more information.) Please also check the comments below on 32-bit vs. 64-bit mode. To find out which actual search options the LAMA 2011 configuration corresponds to, check the source code of the src/driver/aliases.py module.

32-bit mode or 64-bit mode?

Our current codebase (as of November 2011) differs from the IPC versions of our planners in one way: by default, planner executables are compiled in 32-bit mode, while 64-bit was used at IPC 2011. The main differences between 32- vs. 64-bit mode are as follows:

• 64-bit mode is faster than 32-bit mode (in our limited experiments typically by a factor of ~1.1)
• 64-bit mode needs more memory than 32-bit mode (in our limited experiments typically by a factor of ~1.5)
• 64-bit mode can use essentially unbounded amounts of memory, while 32-bit mode can only use 3 GB of user space memory (on typical Linux systems -- numbers may differ on other operating systems and depending on kernel options)

In our experiments, the memory advantage of 32-bit mode tends to outweigh the speed disadvantage, which is why we enable 32-bit mode by default. See http://issues.fast-downward.org/issue213 for details. However, for memory limits substantially beyond 4 GB, you should use 64-bit mode due to the address space limitations of 32-bit mode.

To enable 64-bit, use the build configurations release64 and debug64. For manual builds, call CMake with the option -DALLOW_64_BIT=TRUE and set up your build environment to compile for 64 bit (this depends on your system). For example, the following would work on Linux with gcc:

mkdir -p builds/manual_64_bit_build
cd builds/manual_64_bit_build
cmake -DALLOW_64_BIT=TRUE -DCMAKE_CXX_FLAGS="-m64" ../../src
make

Other questions?

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