The New Sudoku Players' Forum

by **coloin** » Mon Jan 24, 2022 6:10 pm

champagne wrote:I don't know why

I blame gsfs minlexing treatment

of course there will be an unknown number of DB which have a requirement to have 5+6 clues but actually need 12 ....
these DB could be treated similarly .....

I'm not suggesting for one moment that mathemagics and I generate 900M plus 5+6+12 puzzles from different grids ... :lol:

and of course testing a DB [on your part] for no 11 [ie must be a 12] is faster than testing for a no 12

by **champagne** » Tue Jan 25, 2022 10:45 am

Hi Coloin,

more on this topic.

First of all, I can produce (reliable??) a list expected exhaustive of solution ED grids requiring a minimum of 12 clues just due to the fact that each band requires a minimum of 6 clues.
The best chance to have no valid sub puzzle with 12 clues in is this list where both bands have the minimum count of valid puzzles (band 224 index 0 count = 162)

Hidden Text: Show

in pairs with one or more band requiring less than 6 clues, the number of potential valid bands 1+2 increases sharply, and the chances for none of these to be a valid goes down in the same way.

by **coloin** » Wed Jan 26, 2022 1:28 pm

Hi

I looked at those grids .... there is a difference in band labelling (1;224;237;254;307;413 ) which explains the confusion

It appears that index416 labels bands which need 6 clues as { 1,132,145,168,202,413}

But yes there are grid solutions with 3 bands of (1;224;237;254;307;413 ) which wont have a 17.

And testing those 224 combinations looks like the best chance

by **champagne** » Wed Jan 26, 2022 1:45 pm

Hi coloin,
I run the scan for the 478 pairs index 0+0 listed above.
all of them have valid 12. The smallest number of valid 12 is 57 in the following pair

123456789457189326689327154214598673398674512576213498731942865842765931965831247

This gives nearly no chance to do better with pairs having a bigger number of {valid band 1 * valid band 2}

EDIT : bad error on my side mixing run time in milliseconds and number of valid 12 clues
for the given band, the right count is 113
and the lowest count is 90 for the band

123456789457189326689327154214965873375814962968273415531648297742591638896732541

at the end, the chances to find a minimum 13 clues are still lower

by **coloin** » Wed Jan 26, 2022 11:54 pm

Well done for validating that .... as much as is possible .... and it makes sense as there really isn't room for 13 UAs in a DB....
The misunderstanding was in the labelling of the bands [although 1 and 413 were the same] and I have edited the posted grids.

by **champagne** » Thu Jan 27, 2022 1:31 pm

I checked the 11811 pairs file with bands requiring 6 clues.
I put a filter to 300 valid 2 bands.
out of bands with twice the band index 0, I only have this one

123456789457189326698273514231798465574362198986541237349615872762834951815927643 1 1 102 valid bands 12

So, really, i can't see any chance to have a pair requiring 13 clues

by **debblez** » Mon Feb 20, 2023 3:44 pm

Mathimagics wrote:Ok, the search for new grids with 18C puzzles is now resumed, albeit with only 4 cores (JILL), as JACK is busy helping champagne with the 17C search.

I have rewritten the Gen18C process completely, and it is much simpler, and more efficient, I think. It looks to be achieving an NPH of ~3000 (new grids found per core-hour), which is quite good.

The current 18C grid count is 635,256,482.

Cheers
MM

Have you given up on the LCT project? I find it extremely interesting and your progress very impressive.

by **Mathimagics** » Tue Feb 21, 2023 8:10 pm

Hi debblez!

The LCT project is still active, you will be pleased to know.

champagne has been working hard on building a version of the code that we used to finalise the 17C puzzle count, for use with finding 18C puzzles.

It is hoped that this revised version will be ready for "beta" testing sometime soon.

At this stage, I would guess that we will have the code ready to begin the search sometime in March.

The search will require many cores, over many years (like the 17C search, but longer than that).

Cheers
MM

by **champagne** » Wed Feb 22, 2023 6:47 am

Hi debblez,

A little more after Mathimagics last post.

In the LCT project, Mathimagics did a significant step using the vicinity search to detect solution grids having one or more 18's.
He had to stop when the yield was too bad.

If we know that we have only 49158 ED 17s, the number of ED 18 is huge. I don't have an estimate of this number, but Blue and Mathimagics made an estimate that about 20% of the solution grids have at least one 18. As an average 5 18s per active solution grid is a reasonable bet, We should at the end have more then 5 billions ED 18s.

Blue delivered (not public) a DLL performing well for the 18 search in a unique solution grid. Unhappily, we don't have the sources and Blue withdrew from the project for personal reasons.
I suggested to Mathimagics to apply an improved process derived from the 17 scan to restart the project. Blue's DLL performance showed that we had room for that.

The first challenge was to guess how blue improved his process and to try to reach a similar or better run time. This is a hard job. There is no true economical challenge in the results, so it remains a kind of hobby research on my side and nobody was prepared to work with me on this code.

2 month ago, we were very close to have a beta test with a code approaching the DLL performance (but working in the frame used to scan the 17 field).

Thinking with Mathimagics of the best process to apply in his project, we came to the conclusion that we should change one of the main constraints of blue's design.
This leaded to another change in the last part of the process and pushed to another strategy to implement it.

This is of small (if any) interest for the users, but any change in this process requires many many tests not easy to design.

As wrote Mathimagics, we have now in hands a sound basis, with a code that seems faster than Blue's DLL, I agree that in March, we should have solved several minor performance issues and be in a position to start a beta test version for Mathimagics's project.

I chose to make public the draft of the code. This is consistent with my age and the risks attached the way this is implemented.

I open months ago a separate thread
http://forum.enjoysudoku.com/17clues-v7-scan-18-clues-scan-t40329.html
to give more details on this package. After a long silence, I intended to come back in the next weeks with a summary of the changes in progress.

Out of Mathimagics's project, the source could be modified easily to produce some 18s having specific properties, as for example a distribution in box 222222222, something on which works our friend coloin.

by **coloin** » Wed Feb 22, 2023 2:35 pm

champagne wrote: as for example a distribution in box 222222222, something on which works our friend coloin.

Indeed I have been leisurely generating the extremes of the 18C . [ post forthcoming]. Indeed blue has estimated that these box-222222222 puzzles make up ~ 0.75% of all 18C
I think blue and Afmob independantly estimnated with a high degree of certainty here that there were about

Supersets method - Afmob - 1.9 billion 18C
Grid sampling method - blue - 1.91 billion 18C

Total grids with an 18C : (0.9683 +/- 0.0129) * 10^9 ~ 0.97 billion
60% of grids with an 18C have only one 18C puzzle ,

However it has to be accepted that the the initial generation approach is doomed to only find perhaps 95% of puzzles and never knowingly complete.
The problem lies in that there are many 18C puzzles which are {-2+2} remote of another 18C - so even if we could do a complete {-2+2} we wouldnt find these. Pretty sure thats why mathimagics has regrouped on the project !

Here is a 2-remote 18C

Code: Select all: +---+---+---+ |...|...|...| |...|...|.65| |...|...|.27| +---+---+---+ |..1|38.|...| |..5|...|8..| |..6|..7|...| +---+---+---+ |.4.|.9.|3..| |.2.|...|...| |.7.|..2|..6| +---+---+---+

interesting in that it has empty box 1 and 2, and 4 clues in box 3

and here is ~90% complete list of 154 similar puzzles... which we can probably add most of these to the list

Hidden Text: Show

Code: Select all: ................12.......34.....5.....1..3.....2..46...3..2.....8..6.7..45..9.... ED=2.0/1.2/1.2 ................12.......34.....1.....5..6.....7..8.9..1..7...6.4..5.7...6..9.... ED=2.0/1.2/1.2 ................12.......34.....5.....2..4.....9..36...4..1.....7..6.8..35..9.... ED=2.0/2.0/2.0 ................12.......34..5...6....2..4.....7..8....8..5.....3..6.9...4.21.... ED=2.0/1.2/1.2 ................12.......34.....15....3..2.....6..5....1..3.....5..4....27..8.6.. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..24.....12.......43......7.9..5.. ED=7.2/2.3/2.3 ................12.......34..1........5..67....4.28....2.1......3.4......9...76.. ED=2.0/1.2/1.2 ................12.......34..1.....3..4..5.....6..78...2..1.....3..4.....9...87.. ED=2.0/1.2/1.2 ................12.......34.....15....4..5.....6..2....1..3.....5..4....27..8.6.. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..23.....12.......24......7.9..5.. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..23.....12.......24......7.9..8.. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..24.....12.......43......7.9..8.. ED=7.2/2.3/2.3 ................12.......34.....1....5...67...8..43.....14.......42......7.9..5.. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..43.....14.......42......7.9..8.. ED=2.0/1.2/1.2 ................12.......34..1........5..67....4.28....2.1......3.4......9...78.. ED=2.0/1.2/1.2 ................12.......34..1.....3..4..5.....6..78...2..1.....3..4.....9...85.. ED=2.0/1.2/1.2 ................12.......34..2.....3..4..5.....6..78...9..2.....3..4.....1...85.. ED=2.0/1.2/1.2 ................12.......34..2.....3..4..5.....6..78...9..2.....3..4.....1...87.. ED=2.0/1.2/1.2 ................14.......39..9.....3..4..5.....6..78...2..9.....3..4.....1...87.. ED=2.0/1.2/1.2 ................31.......94..1.....3..4..5.....6..78...2..1.....3..4.....9...85.. ED=2.0/1.2/1.2 ................12.......343....1....5...67.......4...8.12.......43......7.9..5.. ED=7.2/1.2/1.2 ................12.......34.....1....5...67..28...4.....12.......43.....7..9..5.. ED=2.0/1.2/1.2 ................12.......34..1........5..87....4.2.....2.1......3.46.....9...76.. ED=7.2/2.3/2.3 ................12.......34..1..5.....5..67....4.2.....2.1......3.4......9.7..6.. ED=7.2/2.3/2.3 ................12.......34..1..5.....5..67....4.2.....2.1......3.4......9.8..6.. ED=7.2/2.3/2.3 ................12.......34..1..5.....5..67....4.2.....2.1......3.4......9..8.6.. ED=7.2/2.3/2.3 ................12.......34..1........5..67....4.2.....2.17.....3.4......9..8.6.. ED=7.2/1.2/1.2 ................12.......34..1........5..67....4.2.....2.1......3.48.....9..7.6.. ED=7.2/1.2/1.2 ................12.......34..1........5..67....4.28....2.1......3.4......9..7.8.. ED=2.0/1.2/1.2 ................12.......34.....12...5...67...8..23.....1........24......7.9..5.. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..23.....1...3....24......7.9..5.. ED=2.0/1.5/1.5 ................12.......34.....1....5...67...8..23.....1........24......7.9.85.. ED=2.0/1.5/1.5 ................12.......34.....1....5...67...8..23.....1........24......7.9..52. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..23.....12.......24.....7..9..5.. ED=2.0/1.2/1.2 ................12.......34.....1...8....67..5...23.....12.......24......7.9..5.. ED=2.0/1.2/1.2 ................12.......34..4..1....5...67...8...3.....12........4.....37.9..5.. ED=2.0/1.5/1.5 ................12.......34.....12...5...67...8..23.....1........24......7.9..8.. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..23.....1...3....24......7.9..8.. ED=2.0/1.5/1.5 ................12.......34.....1....5...67...8..23.....1........24......7.9.58.. ED=2.0/1.5/1.5 ................12.......34.....1....5...67...8..23.....1........24......7.9..82. ED=2.0/1.2/1.2 ................12.......34.....14...5...67...8..43.....1........42......7.9..5.. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..43.....1...3....42......7.9..5.. ED=2.0/1.5/1.5 ................12.......34.....1....5...67...8..43.....1........42......7.9.85.. ED=2.0/1.5/1.5 ................12.......34.....1....5...67...8..43.....1........42......7.9..54. ED=2.0/1.2/1.2 ................12.......34..2..1....5...67...8...3.....14........2.....37.9..5.. ED=2.0/1.5/1.5 ................12.......34.....14...5...67...8..43.....1........42......7.9..8.. ED=2.0/1.2/1.2 ................12.......34.....1....5...67...8..43.....1...3....42......7.9..8.. ED=2.0/1.5/1.5 ................12.......34.....1....5...67...8..43.....1........42......7.9.58.. ED=2.0/1.5/1.5 ................12.......34.....1....5...67...8..43.....1........42......7.9..84. ED=2.0/1.2/1.2 ................12.......34..1..5.....5..67....4.2.....2.1......3.4......9..7.8.. ED=7.2/2.3/2.3 ................12.......34..1........5..67....4.2.....2.18.....3.4......9..7.8.. ED=7.2/2.3/2.3 ................12.......34..1........5..67....4.2.....2.1......3.48.....9..7.8.. ED=7.2/2.3/2.3 ................49.......78..4..8.....12..5....9..7....8.......47..5.....6..3.2.. ED=4.5/2.0/2.0 ................32.......14.....1....5...67..28...4.....12.......43.....7..9..5.. ED=2.0/1.2/1.2 ................32.......14..1........5..67....4.2.....2.17.....3.4......9..8.6.. ED=7.2/1.2/1.2 ................32.......14..1........5..67....4.2.....2.1......3.48.....9..7.6.. ED=7.2/1.2/1.2 ................32.......14..1........5..67....4.28....2.1......3.4......9..7.8.. ED=2.0/1.2/1.2 ................12.......34..4..1....5...68...8...3.....12........4.....37.9..5.. ED=2.0/1.5/1.5 ................12.......34..2..1....5...68...8...3.....14........2.....37.9..5.. ED=2.0/1.5/1.5 ................32.......14..1........5..67....4.2.....2.18.....3.4......9..7.8.. ED=7.2/2.0/2.0 ................32.......14..1........5..67....4.2.....2.1......3.48.....9..7.8.. ED=7.2/2.0/2.0 ................49.......78..4..8.....12..3....9..7....8.......47..5.....6..3.2.. ED=4.5/2.0/2.0 ................49.......78..4..8.....12..5....9..7....8........7.65.....6..3.2.. ED=2.0/1.2/1.2 ................49.......78..4..8.....12..3....9..7....8........7.65.....6..3.2.. ED=2.0/1.2/1.2 ................49.......78..4..8.....12..5....9..7....8.56.....7........6..3.2.. ED=2.0/1.2/1.2 ................49.......78..4..8.....12..5....9..7....8........7.65.2...6..3.... ED=2.0/1.2/1.2 ................12.......34.....5.....6..28...79..1.......3.6..4...7....52..4.... ED=2.0/1.2/1.2 ................12.......34.....1.....3..4.....5..67...4..8.....16.7....2...5.8.. ED=2.0/1.2/1.2 ................12.......34.....1.....5..7....78..26......9.8..1...4...74...3.... ED=2.0/1.2/1.2 ................12.......34.....1.....5..67...64..2....7..4.8..1...9....2...3.... ED=2.0/1.2/1.2 ................12.......34.....1.....5..67...64..2...1...7....2...3.....8..4.9.. ED=2.0/1.2/1.2 ................32.......14.....1....5...87..68...4.....12.......43.....7..9..5.. ED=2.0/1.2/1.2 ................32.......14.....1....5...6...68...47....12.......43.....7..9..5.. ED=2.0/1.2/1.2 ................59.......78..4..8.....52..3....9..7....8........7.65.....6..3.2.. ED=2.0/1.2/1.2 ................43.......78..4..8.....32..5....9..7....8........7.65.2...6..3.... ED=2.0/1.2/1.2 ................15.......74.....5.....6..28...79..1.......3.6..4...7....52..4.... ED=2.0/1.2/1.2 ................15.......34.....5.....6..28...79..1.......3.9..4...7....52..4.... ED=2.0/1.2/1.2 ................12.......74.....5.....6..28...79..1.......3.6..41..7....5...4.... ED=2.0/1.2/1.2 ................12.......74.....5.....6..28...79..1.......3.6..42..7....5...4.... ED=2.0/1.2/1.2 ................12.......34.....1.....6..7....75..26......9.8..1...4...74...3.... ED=2.0/1.2/1.2 ................12.......34.....1.....8..69...64..2....7..4.8..1...9....2...3.... ED=2.0/1.2/1.2 ................12.......34.....2.....6..58...79..1.......3.6..4...7....25..4.... ED=2.0/1.2/1.2 ................15.......34.....5.....6..18...79..2.......3.9..4...7....52..4.... ED=2.0/1.2/1.2 ................15.......34.....5.....6..28...39..1.......7.9..4...3....52..4.... ED=2.0/1.2/1.2 ................13.......78..1..8.....32..4....9..7....8........7.65.2...6..3.... ED=2.0/1.2/1.2 ................13.......78..1..8.....32..5....9..7....8........7.65.9...6..3.... ED=2.0/1.2/1.2 ................41.......78..4..8.....12..3....9..7....8........7.65.9...6..1.... ED=2.0/1.2/1.2 ................14.......263.1..5.....6..1...7....48...54.6........3.7......9.... ED=2.0/1.2/1.2 ................15.......231....5.....2..1.....7..89......6.....9..2.7..58..3.... ED=2.0/1.2/1.2 ................13.......56..3..6...2.6..5........49...9..2.8......3....57..1.... ED=2.0/1.2/1.2 ................13.......56..3..6...2.6..5........87...9..2.4......3....57..1.... ED=2.0/1.2/1.2 ................18.......56..3..6...1.6..5........27...9..8.4......3....57..1.... ED=2.0/1.2/1.2 ................83.......259.3..6........5...8....2....2..9...6.5..3.....7..1.4.. ED=2.0/1.2/1.2 ................18.......251.3..6.....8..2........5....2..1.....5..3..6..7..9.4.. ED=2.0/1.2/1.2 ................15.......27..1..2.....6..38....51......2..9.3...7.56.....4....... ED=2.0/1.2/1.2 ................16.......57..1........7..9.....56.43...9.7......6..1.....2..3.8.. ED=2.0/1.2/1.2 ................15.......74.....5.....6..2....79..18......3.9..4...7....52..4.... ED=2.0/1.2/1.2 ................15.......34.....5.....6..2....79..18......3.9..4...7....52..4.... ED=2.0/1.2/1.2 ................15.......34.....5.....6..2....79..18......3.9..42..7....5...4.... ED=2.0/1.2/1.2 ................12.......34...4.2.....6..5....7...18......3.6..4...7....25..4.... ED=2.0/1.2/1.2 ................12.......34.....2.....6..5....79..18......3.6..45..7....2...4.... ED=2.0/1.2/1.2 ................15.......26..3..69....8..7.....42.5....2..3.4..76...........1.... ED=2.0/1.2/1.2 ................16.......29..8..2.....1..9.....5..43...9........7..6.....2.15.7.. ED=2.0/1.2/1.2 ................18.......56.6...9.....2..37.......8...65..4.....9..2.4...1..7.... ED=2.5/1.2/1.2 ................16.......73..1..3.....5.149....6.......7.25.....8.6......3....2.. ED=2.0/1.2/1.2 ................48.......67.....65..1.8..7.....4..2....9..8...5....4.....7..1.3.. ED=2.0/1.2/1.2 ................15.......69...8.5.....7..14....6......19..4.....5..7.2...8..2.... ED=2.0/1.2/1.2 ................15.......69...8.5.....2..17....6......19..4.....5..2.4...8..7.... ED=2.0/1.2/1.2 ................16.......23..1..3...3.5..49.......2.......1.8..49..6.....2..7.... ED=2.0/1.2/1.2 ................31.......27..6..7.....8..2.7.9.4..5.......8.6..25..3........1.... ED=2.6/1.2/1.2 ................15.......283.4..59.......8.5...7..1.....9.6.4......2.....8..3.... ED=2.0/1.2/1.2 ................15.......283.4..59.......8.5...7..1.....9.6.7......2.....8..3.... ED=2.0/1.2/1.2 ................18.......253.4..59.......8.5...7..1.....9.6.7......2.....8..3.... ED=2.0/1.2/1.2 ................14.......268....5.....6..1...7....43.1.54.6........8.7......9.... ED=2.0/2.0/2.0 ................15.......36...8.5.....2..1.....6...7..15..4.....3..7.4...8..2.... ED=2.0/1.2/1.2 ................15.......96...8.5.....2..1.....6...7..15.3......9..2.4...8..7.... ED=2.3/1.2/1.2 ................65.......21..8...9....51.7.....6.......1..8...2.7.49.....2..3.... ED=2.6/1.2/1.2 ................62.......15..8.4.3....7..1.....5.......1....2...6..9.....2.73.4.. ED=2.0/1.2/1.2 ................62.......15..8.4.9....7..1.....5.......1....2...6..9.....2.73.4.. ED=2.0/1.2/1.2 ................65.......12..8.4.3....7..1.....5.......1....2...6..9.....2.73.4.. ED=2.0/1.2/1.2 ................16.......57..1........7..9.....56.83...9.7......6..1.....2..3.8.. ED=2.0/1.2/1.2 ................12.......94...4.2.....6..5....7...18......3.6..4...7....25..4.... ED=2.0/1.2/1.2 ................12.......34...4.2.....6..5....7...18......3.6..4...7....25.1..... ED=2.0/1.2/1.2 ................12.......94...4.2.....6..5....7...18......3.6..4...7....25.1..... ED=2.0/1.2/1.2 ................48.......67.....69..1.8..7.....4..2....3..8...5....4.....7..1.3.. ED=2.0/2.0/2.0 ................25.......183.4..59.......8.5...7..1.....9.6.4......2.....8..3.... ED=2.0/1.2/1.2 ................15.......36...8.5.....2..1.....6...7..15...8....3..7.4...8..4.... ED=2.0/1.2/1.2 ................51.......96...8.5.....2..1.....6...7..15.3......9..2.4...8..7.... ED=2.3/1.2/1.2 ................12.......65..8.4.9....7..1.....5.......1....2...6..9.....2.73.4.. ED=2.0/1.2/1.2 ................12.......36...2.5.....8..1.....6...7..15...2....3..7.4...2..4.... ED=2.0/1.2/1.2 ................15.......23...8.5.....6..1.....2...7..15...8....3..7.4...8..4.... ED=2.0/1.2/1.2 ................15.......36...8.5.....2..1.....3...7..15...8....8..2.4...6..7.... ED=2.0/1.2/1.2 ................18.......23...8.5.....6..1.....2...7..15...8....3..7.4...8..4.... ED=2.0/1.2/1.2 ................18.......36...8.5.....2..1.....6...7..15...8....8..2.4...3..7.... ED=2.0/1.2/1.2 ................51.......26...8.5.....3..1.....4...7..15.2......9..6.4...8..7.... ED=2.3/1.2/1.2 ................94.......28.....2...4.1..8........73..9.2.4.....7..1.5...3..9.... ED=5.6/1.2/1.2 ................94.......28.....2...4.1..8........73..9.2.4.....7..1.5...5..9.... ED=4.5/1.2/1.2 ................16.......27..67.4.....5.9.8....1.......4....3...7.25.....2..8.... ED=2.0/1.2/1.2 ................19.......27..6..7.....8..54..97...2.......8.6..25..3........1.... ED=2.0/1.2/1.2 ................16.......27..12.7.....5..9.....9..48..47...........5.3...2..8.... ED=2.0/1.2/1.2 ................15.......36...8.5.....7..1.....2...7..95...8....8..2.4...1..6.... ED=3.4/1.2/1.2 ................19.......87..4........1.2.3....9..7..6.8.15.2...7........6..3.... ED=2.3/1.2/1.2 ................49.......28..4..6...1.3..87.......2....2..9.....7..4.5...8.1..... ED=2.0/1.2/1.2 ................97.......24.7...58....2..1.....4..8...51..6........7..4..8..9.... ED=3.4/1.2/1.2 ................15.......36...5.9.....2..1.....6...7..15.9......9..7.4...3..4.... ED=2.0/1.2/1.2 ................67.......12..7.4.3....6..1.8...5.......1........8..9.....2.73.4.. ED=2.3/1.2/1.2 ................17.......92..91.7.....6...5.......4....4.28.3...7..5....1...3.... ED=2.0/1.2/1.2 ................65.......27..138......5...8....6..7....4..9.3...2........7...2..6 ED=2.0/1.2/1.2 ................16.......72..12.7.....5..9.....9..48..47...........5.3...2..8.... ED=2.0/1.2/1.2 ................18.......747.34.......8..9.....4..59...6..7.....1....5.....34.... ED=2.0/1.2/1.2 ................16.......27..12.7.....59.......9..48..47...........5.3...2..6.... ED=2.0/1.2/1.2 ................15.......36...8.5.....7..1.....2...7..95..4.....8..2.4...1..6.... ED=2.0/1.2/1.2 ................19.......87..4........1.2.3..8....7..6..315.2...7........6..3.... ED=2.6/1.2/1.2 ................67.......12..7.4.3..2....1.8...5.......1........8..9......973.4.. ED=2.6/1.2/1.2

by **dobrichev** » Thu Feb 23, 2023 3:29 am

I'm glad the project is active.

by **Mathimagics** » Thu Feb 23, 2023 7:38 am

.
Thanks Mladen for your moral support! 8-)

And thanks Colin for your succinct observations regarding the "state of play" (not to mention the millions of puzzles you contributed to the initial vicinity search)!

coloin wrote:I think blue and Afmob independently estimated ... that there were about

Supersets method - Afmob: 1.9 billion 18C
Grid sampling method - blue: 1.91 billion 18C

Total grids with an 18C : (0.9683 +/- 0.0129) * 10^9 = estimated 0.97 billion

However, it has to be accepted that the initial generation approach is doomed to only find perhaps 95% of puzzles and never knowingly complete.

The problem lies in that there are many 18C puzzles which are {-2+2} remote of another 18C - so even if we could do a complete {-2+2} we wouldnt find these.

Pretty sure that is why mathimagics has regrouped on the project !

Exactly! It is only with a systematic comprehensive approach that we can locate the missing 18's, and be able to make a claim to completeness of the results.

There are two possible approaches that we can take:

plan B: use blue's DLL to test every grid

plan C: use champagne's code to enumerate all the 18C's

We believe that plan C will take less time than plan B. champagne's code should be faster overall, but to what extent remains to be seen. The time comparisons will become more clear when we do production testing in March.

Finally, I should note (again), blue's DLL remains the only method to test a grid explicitly for having an 18C. Without it, we would be totally in the dark - we would have no way to verify that champagne's code is correct. This project would probably be dead in the water without blue's contribution.

Cheers
MM

by **champagne** » Thu Feb 23, 2023 7:45 am

Mathimagics wrote:.

Finally, I should note (again), blue's DLL remains the only method to test a grid explicitly for having an 18C. Without it, we would be totally in the dark - we would have no way to verify that champagne's code is correct. This project would probably be dead in the water without blue's contribution.

Cheers
MM

Gridchecker can do this, but is much too slow to make it feasible, so yes, at the end you can write that Blue's DLL is to-day the only working process.

by **champagne** » Thu Feb 23, 2023 8:06 am

just some remarks linked to hard discussions here and there in other threads.

The code written here uses many "native instructions" of the families of processors having the same set of instructions than Intel processors.

The code is implemented using visual C++, but verified wit g++ to have the compatibility with LINUX.

Although we have no GUI here, we faced several portability problems that our expert mladen solved in due time. Thanks again to him.
Use of "native" instructions (as popcout, bitscan, use of 128 bits registers..) has been done to meet the performance requirements.

Here, discussion of the compatibility with a processor having another set of instructions has no interest.

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