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LP solver support

Some configurations of the search component of Fast Downward, such as optimal cost partitioning for landmark heuristics, require a linear programming (LP) solver and will complain if the planner has not been built with support for such a solver.

Instructions for building Fast Downward with LP support

To enable LP support in Fast Downward, you need the Open Solver Interface (OSI) and (optionally but recommended) an external solver such as CPLEX installed on your system (see below). Once OSI is installed, you can build Fast Downward with LP support by calling make with the option DOWNWARD_USE_LP=1. This option can be either set as an environment variable or given to make in the commandline. If OSI is not installed in /opt/coin, you also need to set DOWNWARD_COIN_ROOT to its installation path.

make distclean
make DOWNWARD_USE_LP=1 DOWNWARD_COIN_ROOT=/path/to/coin

Installing CPLEX

IBM offers a free academic license that includes access to CPLEX. Once you are registered, you can download a binary from the member area of the Academic Initiative Website. Execute the binary and follow the guided installation. If you want to install in a global location, you have to execute the installer as root.

After the installation, set the following environment variables (adapt the paths if you did not install in the default location):

export DOWNWARD_CPLEX_INCDIR=/opt/ibm/ILOG/CPLEX_Studio1251/cplex/include/ilcplex
export DOWNWARD_CPLEX_LIBDIR=/opt/ibm/ILOG/CPLEX_Studio1251/cplex/lib/x86_sles10_4.1/static_pic

Installing the Open Solver Interface on Linux

These instructions apply to COIN/OSI 0.103.0, which was the last version that was bundled with Fast Downward. Newer versions from http://www.coin-or.org/download/source/Osi/ should work, too. If you experience problems, please let us know.

OSI provides a common interface to different LP solvers. OSI must be compiled after installing the solver. If you install a solver later, repeat the installation steps of OSI. We assume in the following that CPLEX and Gurobi are installed and the environment variables DOWNWARD_CPLEX_INCDIR, DOWNWARD_CPLEX_LIBDIR, DOWNWARD_GUROBI_INCDIR and DOWNWARD_GUROBI_LIBDIR are set up correctly. We only tested CPLEX so far. Only include options for the solvers you have installed.

   1 wget http://www.coin-or.org/download/source/Osi/Osi-0.103.0.tgz
   2 tar xvzf Osi-0.103.0.tgz
   3 cd Osi-0.103.0
   4 
   5 sudo ./configure CC="gcc"  CFLAGS="-m32 -pthread -Wno-long-long" \
   6                  CXX="g++" CXXFLAGS="-m32 -pthread -Wno-long-long" \
   7                  LDFLAGS="-L$DOWNWARD_CPLEX_LIBDIR -L$DOWNWARD_GUROBI_LIBDIR" \
   8                  --without-lapack --enable-static=yes \
   9                  --prefix="/opt/coin" \
  10                  --with-cplex-incdir=$DOWNWARD_CPLEX_INCDIR --with-cplex-lib="-lcplex -lm" \
  11                  --with-gurobi-incdir=$DOWNWARD_GUROBI_INCDIR --with-gurob-lib="-lgurobi"
  12 sudo make
  13 sudo make install
  14 cd ..
  15 rm -rf Osi-0.103.0
  16 rm Osi-0.103.0.tgz

After installation, set the environment variable DOWNWARD_COIN_ROOT to the prefix you used in the call to ./configure.

Installing the Open Solver Interface on Mac OS X

The installation above has been reported to fail on Mac OS X due to a bug in the CoinUtils configure script. (See issue295.) If you run into this problem, try downloading the patched file attached to this page, make it executable, and replace the file Osi-0.103.0/CoinUtils/configure with it:

    cp Dowloads/coinutils-configure.patched Osi-0.103.0/CoinUtils/configure
    chmod +x Osi-0.103.0/CoinUtils/configure

Otherwise, the instructions are identical to the Linux instructions above with the following changes:

Replace -m32 with -arch i386.
Replace --enable-static=yes with --enable-static=no.

If LP setup fails

The LP solver has a number of dependencies which might not be installed on your system. If for some reason the LP setup step fails, we would appreciate if you could attempt to troubleshoot it yourself.

If the configure step fails for COIN/OSI, have a look at their troubleshooting page. If you get warnings about unresolved references with CPLEX, visit their help pages.

If after troubleshooting you can get the LP package to work, please do let us know of your problem and its solution so that we can improve these instructions. If you still cannot get it to work, we may be able to provide some help, but note that the LP solver is an external package not developed by us.

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