Textworld

Released on July 26, 2020.

Highlights:

- The Singularity and Docker distributions of the planner now include
LP support using the SoPlex solver out of the box. Thank you to ZIB
for their solver and for giving permission to include it in the
release.

- The Vagrant distribution of the planner now includes LP support
using the SoPlex and/or CPLEX solvers out of the box if they are
made available when the virtual machine is first provisioned. See
<http://www.fast-downward.org/QuickStart> for more information.

- A long-standing bug in the computation of derived predicates has
been fixed. Thanks to everyone who provided bug reports for their
help and for their patience!

- A new and much faster method for computing stubborn sets has been
added to the planner.

- The deprecated merge strategy aliases `merge_linear` and `merge_dfp`
have been removed.

Details:

- Fix crash of `--show-aliases` option of fast-downward.py.

- Fix incorrect computation of derived predicates.
<http://issues.fast-downward.org/issue453>
Derived predicates that were only needed in negated form and
cyclically depended on other derived predicates could be computed
incorrectly.

- Integrate new pruning method `atom_centric_stubborn_sets`.
<http://issues.fast-downward.org/issue781>
We merged the code for the SoCS 2020 paper "An Atom-Centric
Perspective on Stubborn Sets"
(<https://ai.dmi.unibas.ch/papers/roeger-et-al-socs2020.pdf>). See
<http://www.fast-downward.org/Doc/PruningMethod>.

- Remove deprecated merge strategy aliases `merge_linear` and `merge_dfp`.
The deprecated merge strategy aliases `merge_linear` for linear
merge strategies and `merge_dfp` for the DFP merge strategy are no
longer available. See http://www.fast-downward.org/Doc/MergeStrategy
for equivalent command line options to use these merge strategies.

- For developers: use global logging mechanism for all output.
<http://issues.fast-downward.org/issue963>
All output of the planner is now handled by a global logging
mechanism, which prefaces printed lines with time and memory
information. For developers, this means that output should no longer
be passed to `cout` but to `utils::g_log`. Further changes to
logging are in the works.

- For developers: store enum options as enums (not ints) in Options objects.
<http://issues.fast-downward.org/issue962>

- For developers: allow creating Timers in stopped state.
<http://issues.fast-downward.org/issue965>

Released on December 20, 2019.

Highlights:

- Fast Downward no longer supports Python 2.7, which reaches its end
of support on January 1, 2020. The minimum supported Python version
is now 3.6.

- Fast Downward now supports the SoPlex LP solver.

Details:

- general: raise minimum supported Python version to 3.6
<http://issues.fast-downward.org/issue939>
Fast Downward now requires Python 3.6 or newer; support for Python 2.7 and
Python 3.2-3.5 has been dropped. The main reason for this change is Python 2
reaching its end of support on January 1, 2020. See
https://python3statement.org/ for more background.

- LP solver: add support for the solver [SoPlex](https://soplex.zib.de/)
<http://issues.fast-downward.org/issue752>
The relative performance of CPLEX and SoPlex depends on the domain and
configuration with each solver outperforming the other in some cases.
See the issue for a more detailed discussion of performance.

- LP solver: add support for version 12.9 of CPLEX
<http://issues.fast-downward.org/issue925>
Older versions are still supported but we recommend using 12.9.
In our experiments, we saw performance differences between version
12.8 and 12.9, as well as between using static and dynamic linking.
However, on average there was no significant advantage for any
configuration. See the issue for details.

- LP solver: update build instructions of the open solver interface
<http://issues.fast-downward.org/issue752>
<http://issues.fast-downward.org/issue925>
The way we recommend building OSI now links dynamically against the
solvers and uses zlib. If your existing OSI installation stops
working, try installing zlib (sudo apt install zlib1g-dev) or
re-install OSI (http://www.fast-downward.org/LPBuildInstructions).

- merge-and-shrink: remove trivial factors
<http://issues.fast-downward.org/issue914>
When the merge-and-shrink computation terminates with several factors
(due to using a time limit), only keep those factors that are
non-trivial, i.e., which have a non-goal state or which represent a
non-total function.

- tests: use pytest for running most tests
<http://issues.fast-downward.org/issue935>
<http://issues.fast-downward.org/issue936>

- tests: test Python code with all supported Python versions using tox
<http://issues.fast-downward.org/issue930>

- tests: adjust style of Python code as suggested by flake8 and add this style
check to the continuous integration test suite
<http://issues.fast-downward.org/issue929>
<http://issues.fast-downward.org/issue931>
<http://issues.fast-downward.org/issue934>

- scripts: move Stone Soup generator scripts to separate repository at
https://github.com/aibasel/stonesoup.
<http://issues.fast-downward.org/issue932>

Released on June 11, 2019.
First time-based release.


Changelog

This changelog follows the following convention [https://keepachangelog.com/en/1.0.0/](https://keepachangelog.com/en/1.0.0/).

Fixed
- Fix security issue [[301](https://github.com/microsoft/TextWorld/pull/301)]
- Fix requirements and Inform7 links [[303](https://github.com/microsoft/TextWorld/pull/303)]
- Fix gym version [[305](https://github.com/microsoft/TextWorld/pull/305)]
- Fix documentation [[306](https://github.com/microsoft/TextWorld/pull/306)]
- Rename main branch and references to it [[307](https://github.com/microsoft/TextWorld/pull/307)]
- Use functools.partial instead of lambda functions. It's more multiprocessing friendly. [[294](https://github.com/microsoft/TextWorld/pull/294)]
- Wait for visualization server to be ready before connecting with Selenium. [[294](https://github.com/microsoft/TextWorld/pull/294)]
- Use constants' type as their name instead of `None`. [[293](https://github.com/microsoft/TextWorld/pull/293)]

Removed

- Remove MacOS 10.14 CI. [[294](https://github.com/microsoft/TextWorld/pull/294)]