New Version

I'm not sure if this project is still active but I have recently developed it further to include 'X-wing' solutions of order 2, 3 (swordfish) and 4 (jellyfish). I've also fixed a problem that occurrs in php 5.2.8 due to changes in the _to_string operation. I'm not sure how to post the code here but I can email it to the author if interested. It still does not solve the 'hard' example but it now solves everything in 'Extreme Sudoku' by Wayne Gould.

Hi Mike,
This is the true spirit of open source!
Yes, I would like to post your new version!
Please send it to me and I will do that.

I did not look at the package for quite a while, it is a hobby project after all. But I am still planning to do also the last resort: brute force tree walking, so that it can really solve every puzzle. But I still think that its solution strategy should be humanly understandable, therefore brute force is not really interesting.
Cheers, Ghica

Hi Ghica,

Did you get my new code? I sent it to the email address you have on this site.

I have been extending the program further to include XY and Single Chains. The XY Chains now mean the hard puzzle can be solved logically.

Mike

Yes, I got your code. I will post it, but I first wanted to try it out.
Cheers, Ghica.

The new code has been posted. Works great! Thanks for the good work Mike.
I hope this will inspire me to fresh-up the UI a bit.