constraint based killer sudoku solver performance improvements

[Blockheads Oi Oi]

On 27/01/2012 07:47, Blockheads Oi Oi wrote:
> On 27/01/2012 06:57, Frank Millman wrote:
>>
>> "Blockheads Oi Oi"<breamoreboy at yahoo.co.uk> wrote:
>>
>>> I have a working program based on [1] that sets up all different
>>> constraints for each row, column and box and then sets exact sum
>>> constraints for each cage. It'll run in around 0.2 secs for a simple
>>> problem, but a tough one takes 2 hours 45 minutes. I did some research
>>> into improving the performance and found [2] but can't work out how to
>>> implement the constraints given. Can someone please help, assuming that
>>> it's even possible.
>>>
>>> [1] http://pypi.python.org/pypi/python-constraint/1.1
>>> [2] http://4c.ucc.ie/~hsimonis/sudoku.pdf
>>
>> I don't have an answer, but are you aware of this -
>>
>> http://www.ics.uci.edu/~eppstein/PADS/Sudoku.py
>>
>> It is a sudoko solver written in pure python.
>>
>> I don't know what you call a tough problem, but this one solves the
>> hardest
>> one I have thrown at it in the blink of an eye. It also outputs a full
>> trace
>> of the reasoning it used to arrive at a solution.
>>
>> Frank Millman
>>
>
> I'd looked at this years back and forgotten all about it so thanks for
> the reminder :) Some of the code names directly match ideas given in my
> [2] above so I'll take another look.

Just for the record I ended up using gecode-python and 2 hours 45 
minutes became 2 milli seconds with the same model.  As most politicains 
have been known to say, lessons will be learned :)

-- 
Cheers.

Mark Lawrence.