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Subject: Re: Diep beats Crafty!

Author: Keith Evans

Date: 22:05:35 07/07/04

Go up one level in this thread


On July 08, 2004 at 00:06:12, Robert Hyatt wrote:

>On July 07, 2004 at 23:45:53, Keith Evans wrote:
>
>>On July 07, 2004 at 22:56:46, Robert Hyatt wrote:
>>
>>>On July 07, 2004 at 20:55:10, Mike Byrne wrote:
>>>
>>>>On July 07, 2004 at 11:51:44, Gian-Carlo Pascutto wrote:
>>>>
>>>>>...in the blitz tournament :)
>>>>>
>>>>>Couldn't get a PGN yet.
>>>>>
>>>>>--
>>>>>GCP
>>>>
>>>>Whew - I thought you meant at long time controls.  We all know anything cna
>>>>happen in Blitz, just ask Topalov.
>>>>
>>>>;>)
>>>
>>>
>>>I have not looked at the games.  But Peter and I discussed this and we chose to
>>>use my wide-open ICC book for these games to avoid giving away anything about
>>>his tournament preparation.
>>>
>>>I knew that we would bust one or more openings.  The one thing I forgot is that
>>>I cleverly copied my binary books from my xeon to the opteron.  Doesn't work.
>>>90% of my book was unusable leading to some bizarre opening choices.  I did that
>>>late at night and just forgot that even though the opteron and xeon are both
>>>little-endian, the opteron has a longer struct padding (to 8 bytes rather than 4
>>>bytes) which kills my binary book copy.
>>>
>>>Stupid.  Stupid.  Stupid.
>>>
>>>I should have remembered.  :(
>>
>>Is there any way that you can have crafty automatically detect that a binary
>>book has been "corrupted" in this fashion? This seems worth doing. If you made
>>this mistake, then surely a lot of other people will make the same mistake.
>
>No.  But there is a plan to have a portable binary format for Crafty.  Part of
>the code is written.  The rest will be finished after the WCCC, and will start
>version 20.0 with a new binary book format.  I'll read byte-by-byte and pack the
>bytes into a struct after reading, to avoid this endian stuff and varying
>lengths for floating point and binary numbers and the structure padding
>incompatibilities.
>
>IE when I get this finished, a book.bin will be transportable to any
>architecture and this problem will be history.  That is the only responsible way
>to solve this mess...
>
>I can't "detect" it unfortunately, although I could add a signature to the end
>of the file (the same as I do for the version) to note that it was big endian,
>little endian, and 32 vs 64 bit.  But the architecture independent approach is
>better for obvious reasons.

I didn't know that you were planning on this. It's definitely much better to be
able to use a book, than to see a message "Sorry your book isn't compatible
please try again."



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