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[trivial] Further polishing of the change log for the upcoming release.
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maltehelmert committed Oct 10, 2024
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Expand Up @@ -16,23 +16,42 @@ Released on October 10, 2024.
Highlights:

- We have improved the translator in several dimensions. Key
improvements include a revised and faster version of the invariant
algorithm, full support for negated predicates in the goal, and
improved error reporting for invalid PDDL. In addition, we have
moved the generation of negated axioms to the search component,
which can significantly improve the performance of configurations
that do not rely on negated axioms.

- We have implemented a new theory of landmark progression that, among
other things, closes a completeness gap for search configurations
like LAMA. Furthermore, this change makes it possible to use
reasonable orders for admissible landmark heuristics.

- We added the delete-relaxation operator-counting constraints
described by Masood Feyzbakhsh Rankooh and Jussi Rintanen.

- We have modernized the CMake build system, which now requires a
minimal version of CMake 3.16.
improvements include better error reporting for invalid PDDL,
revised and faster version of the invariant algorithm and full
support for negated predicates in the goal.

- Negated axioms are now computed in the search component, and only in
configurations that actually use them. This eliminates a worst-case
exponential performance bottleneck in cases where negated axioms are
not used. Heuristics that use negated axioms have a new option
(`axioms=approximate_negative`) to avoid this computation at the
cost of some heuristic accuracy.

- There are many improvements to the `landmark_sum` and
`landmark_cost_partitioning` heuristics. This includes a new theory
of landmark progression that fixes a gap in the completeness in
search configurations like LAMA and can deal directly with cyclic
landmark orders, support for reasonable orders in admissible
landmark heuristics, a cleaner definition of preferred operators,
deterministic synthesis of reasonable orders, and performance
improvements. Please note that the command-line options for landmark
heuristics have changed.

- We added a new set of operator-counting constraints
(`delete_relaxation_rr_constraints`), which implements the
delete-relaxation operator-counting constraints by Rankooh and
Rintanen. The old `delete_relaxation_constraints` plugin using the
constraints by Imai and Fukunaga has been renamed to
`delete_relaxation_if_constraints`.

- We added the alias `seq-sat-fdss-2023` for the satisficing Fast
Downward Stone Soup 2023 portfolio from IPC 2023.

- For developers: planner component objects (such as heuristics or
search algorithms) are now constructed with individual parameters
rather than having all parameters encapsulated in an `Options`
object. (We mention this primarily for developers maintaining their
own forks, as this change affects more than 200 source files.)

Details:

Expand All @@ -55,7 +74,7 @@ Details:
requirement to CMake 3.16. New files must now be listed in
src/search/CMakeLists.txt for compilation. For Soplex support, users
need to set the soplex_DIR environment variable instead of
DOWNWARD_SOPLEX_ROOT. Futhermore, we renamed CMake options from
DOWNWARD_SOPLEX_ROOT. Furthermore, we renamed CMake options from
PLUGIN_FF_HEURISTIC_ENABLED to LIBRARY_FF_HEURISTIC_ENABLED.
<https://issues.fast-downward.org/issue1097>

Expand Down Expand Up @@ -101,6 +120,10 @@ Details:
software versions used for our GitHub actions test suite.
<https://issues.fast-downward.org/issue1142>

- infrastructure: Windows builds using CPLEX in GitHub actions now
work with arbitrary repository names.
<https://issues.fast-downward.org/issue1121>

- landmarks, for users: We no longer break cycles in
landmark graphs because landmark progression can now deal
with cycles. Obedient-reasonable orderings are no longer used
Expand Down Expand Up @@ -157,18 +180,17 @@ Details:
<https://issues.fast-downward.org/issue1119>
<https://issues.fast-downward.org/issue1118>

- LP/MIP solvers, bug fix: CPLEX now compiles correctly on Windows for
arbitrary repository names.
<https://issues.fast-downward.org/issue1121>

- merge-and-shrink, for developers: We refactored and simplified the code
of the `merge_sccs` merge strategy.
<https://issues.fast-downward.org/issue1105>

- operator counting, for users: We implemented the delete-relaxation
operator-counting constraints described in "Efficient Computation and
Informative Estimation of h<sup>+</sup> by Integer and Linear
Programming" (Rankooh and Rintanen, ICAPS 2022).
- operator counting, for users: We added
`delete_relaxation_rr_constraints`, which implements the
delete-relaxation operator-counting constraints described in
"Efficient Computation and Informative Estimation of h<sup>+</sup>
by Integer and Linear Programming" (Rankooh and Rintanen, ICAPS
2022). The old `delete_relaxation_constraints` plugin is now called
`delete_relaxation_if_constraints`.
For details, see
<https://www.fast-downward.org/Doc/ConstraintGenerator#Delete_relaxation_constraints_from_Rankooh_and_Rintanen>
<https://issues.fast-downward.org/issue1134>
Expand Down

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