11feb2025

ver 1.3.1 -- 11feb2025

• Corrected a logic error affecting revisited box configurations.
• Added "inertia", meaning pulls are repeated if advantageous.
• Removed old solution methods 3,4,&5 for enhanced simplicity.
• Replaced old method 3 with a single step method equivalent to the previous version of hbox.
• Added new method 4 that omits the 6th heuristic, that is rarely useful.
• Added an additional sanity check on memory and aborts when when available memory is very low.

25jan2025

ver 1.3.0 -- 25jan2025

• Simplified the name to hbox.
• Added 6th heuristic that drives searching for alternate configurations with equal promise.
• Added better description of "baseline" solution methods 10..15, which are often quite usable, but less robust.
• Renamed "endgame" to "halfway" since it's more descriptive. This signifies a point in the solution search where several heuristics are dropped because their utility has ended.

27dec2024

ver 1.2.0 -- 27dec2024

• Added a 6th command line parm: outputFileName (for sokoban YASC).
• Fixed a problem with the embedded version of hbox5, method 3.

24dec2024

ver 1.1.9 -- 24dec2024

• Fixed embedded version code that is used in my RufasSok, Sokerban, SliderPuzzles apps.
• Added a 5th commandline parameter: TimeOutSec (integer). When omitted the default fallback is 660 seconds.
• Reduced memory-release-delay at end of external solver execution.

13dec24

ver 1.1.8 -- 13dec2024

• Added a memory check to assure its availability: Windows, OSX, linux.
• Enhanced portability of my linux build [by using an old compiler].
• Delayed the endgame, thus giving more time for the full set of heuristics to be in play.
• Added a 5th heuristic that generally improves performance; hence the name.
• Bumped default timeout limit from 10 to 11 minutes; but, al always, (ctrl)-c quits at any time.

1jan2024

ver 1.1.7 -- 2jan2024

• Fixed potential indexing error that adversely affected efficiency.

5dec2023

ver 1.1.6 -- 5dec2023

• Added more tweaks for faster execution.

1dec2023

ver 1.1.5 -- 1dec2023

• Reverted to older & faster splay queue implementation.
• Revised /docs/xsok90times.txt (smaller average).

25nov2023

ver 1.1.4 -- 25nov2023

• Now use preprocessing to determine minimal valid and "live" box positions.
• Extended box-count limitation from 24 to 32.
• Began the rigorous enforcement of theoretical limitations: 32 boxes, 256 valid box positions.
• Restructured data to better conserve memory usage without impacting runtimes.

21nov2023

ver 1.1.3 -- 21nov2023

• Revised an internal list structure; changed a LIFO stack into a FIFO queue. This means that among equal-priority configurations, the first one found is processed first. This is a more typical design, but new to hbox4. The push/move efficiency of solutions are somewhat improved.