This is a fork of Fast Downward extended with an implementation of the h^CFF heuristic and online refinement of explicit conjunctions. This implementation has been used for experiments in the following literature:

It is also the code base of the OLCFF planner that competes in the International Planning Competition 2018.

The heuristic and online-refinement search engines are implemented in src/search/conjunctions. Here's an example configuration to give you an idea how to run the heuristic with online refinement:

./ domain.pddl task.pddl \
    --heuristic "hcff=cff(cost_type=ONE, cache_estimates=false)" \
    --search "ehc_c(hcff, preferred=hcff, cost_type=ONE)"

Fast Downward

Fast Downward is a domain-independent planning system.

For documentation and contact information see

The following directories are not part of Fast Downward as covered by this license:

  • ./src/search/ext

For the rest, the following license applies:

Fast Downward is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later

Fast Downward is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program. If not, see <>.