Hi all,
Just a quick post (too busy am I ...) to let you know
that two new articles from mine do appear published in
the latest May-June issue of Datafile (V24 N3), namely:
- HP-71B Fantastic FOUR
This completes my survey of the awesome HP-71B Math ROM's capabilities featured in my previous HP-71B Math ROM Baker's Dozen (Vols. 1 & 2) articles (Datafile V24N1 & V24N2), with a 14th item, this time entirely dedicated to an amazing and, to most people, unexpected application of the rarely used FOUR keyword. The 8-page article includes an extremely short (8-10 line) subprogram to prove the point, which implements the desired functionality by using FOUR at THREE different places ! :-)
... And in case you might be wondering what it does do in 8 lines, well, just things like this:
5476140724498765145164255055853905531677983738245287518763857813
6327817291924274284391508535323487727034799658219644909081309067
2594828012506046508178728897837083606796788063811574831566277675
2690083042313089454529238719564594664469582430009810470529085361x
8613272483920715414162300723618786418866092062249377500985773606
4662458631705546812446590769217075964055392578377430132675516521
2090736216254127215458485945248165480236637192643292312151263003
6019700443135076274093253344852677580447279631645164021852716383=
4716749222040286496749070068312320467962230019683526396980208929
8144798698912068898209629755548948239606320386278774464309942475
6421364116184973206557156812839712328524690661728138363939626113
9758747743298173466811693657744732258337534982396879492806571297
3710834368617759391402653484418328618757195082961982876828493898
4603039652792831669763120962090875778261102590570752098488793116
2448856828704962797762336439900426048471952149128458059774536742
2290065181199484453117984492752773390888344738900086346330169263
only real fast and with much bigger numbers ...
- HP-71B Sudoku Solver's Sublime Sequel
A sequel to my original 35-line HP-71B Short & Sweet Sudoku Solver published in Datafile V24N2, which improves its speed enormously at the expense of just 10 additional lines of code, for a total of 45 lines (half a regular 80-line printed page), well under 2 Kb. Together they form a combined 19-page article which discusses important techniques for this kind of solvers (e.g., bitboards and boolean operations), plus it includes a thorough, 15-item Test Suite, to allow the reader to test any Sudoku solvers out there, or even his/her own human capabilities.
(Matter of fact, I did have this 'sequel' ready and working perfectly before my originally submitted article was published, and I contacted Datafile's Editor, Bruce Horrocks for him to drop it and publish this improved version instead, which would thus have appeared in V24N2. Bruce agreed, but personal complications arised and I was unable to find enough free time to rewrite the already existing article from scratch, so I further told him to go on with publishing the first version anyway, till I could find the time to submit the improved version properly formatted for its publication in Datafile. This is it!)
I hope you'll enjoy them. Also, in this same issue, "Slow Sudoku on the HP-12C" by Tony Hutchings boldly goes where no one dared before, implementing a Sudoku solver/assistant in both a regular HP-12C as well as a 200-step version for the HP-12C Platinum. For such a fan of the HP-12C as myself, this is really a must reading as well.
Best regards from V.
Edited: 20 June 2005, 5:51 a.m.