Brian Damgaard has published a new version of his great and widely used Sokoban YASC program.
The release notes for this new version:
Improved solver "YASS"
The accompanying YASS level solver has been modified a little so it solves approximately 5% more of the levels in the standard test suites.
For instance, the program can now solve 89 of the 90 levels in the XSokoban test suite.
The YASS solver features two different main solver strategies:
a packing order search and a perimeter search.
The former tries to push boxes to goals in a precomputed order, possibly using temporary parking squares if necessary.
The perimeter search consists of first a backward search and then a forward search toward the frontier game states found by the backward search.
Earlier, the perimeter searches used an A* algorithm, with a chance of finding push-optimal solutions for small levels.
Now the perimeter searches use a greedy algorithm, thereby sacrificing push-optimality for solving more levels.
Support for Sokolution 6.0
The plugin script for running the Sokolution solver program from Sokoban YASC has been updated to match version 6.0 of the solver.
The solver program itself is not bundled with Sokoban YASC and must be downloaded from its own web page.
If you have used Sokolution from Sokoban YASC before, you need to add this new text line (without the quotation marks) to the Sokolution settings:
A better alternative is that you open the Sokolution settings file, delete all its contents, and save the emptied file.
Then Sokoban YASC creates a new file with default values the next time you open the settings.
Please also note that you need to edit the Sokolution program name in the settings each time a new version is released.
- Minor other changes
A feature comparison of the main Sokoban programs can be found in the Sokoban Wiki.