[Bug-gnubg] Makebearoff questions and errors

[Ian Shaw]

What are the trade-offs with specifying different hash sizes? Is there any 
difference between the terms "size of hash" used for 2-sided, and "size of 
cache" used for 1-sided?

Is there any interaction between the one-sided and two-sided databases? Can 
they look up results in each other to save time?
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Is there any demand for pre-generated databases? The 6x8 two-sided one took 
about an hour on my PC, so I'd be happy to do larger ones and make them 
available. Joseph isn't giving us any more rollouts to do, so I can give it 
some CPU time. I could post them on a website, in parts or as a whole.

I can see that it might not be worthwhile because it might be faster to create 
your own rather than download it, but if there's demand I'll do it. If you want 
a particular size let me know. But yow! The size stacks up quickly.

6x8:     72 Mb
6x9:    200 Mb
6x10:   500 Mb
6x12:   1.2 Gb
6x13:   1.5 Gb
6x14:   reports -86 Mb!!
Total number of positions    :   1502337600
Size of resulting file       :   -866201088 bytes
6x15:
Total number of positions    :  -1350385600
Size of resulting file       :   2081817088 bytes

Perhaps there's a problem converting between signed & unsigned integers?
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Is there a way of storing a small(ish) database in the gnubg directory, and 
having a larger one on CD? GnuBg could use the local one where possible and go 
to the CD if it exists.
_____________________________________________________________________________________

I'm having trouble extending my database. I get the message, "Error 
initialising old bearoff database!

Here's my attempt:

C:\GnuBg>makebearoff -v
makebearoff $Revision: 1.17 $

C:\GnuBg>makebearoff -t 6x3 -f 6_3_gnubg_ts.bd
Two-sided database:
Number of points             :            6
Number of chequers           :            3
Calculate equities           : cubeless and cubeful
Write header                 : yes
Number of one-sided positions:           84
Total number of positions    :         7056
Size of resulting file       :        56448 bytes
Size of hash                 :    100000000 bytes
Reuse old bearoff database   : no
Hash status:
Size:    12500000 elements
Queries: 0 (hits: 0)
Entries: 0 (overwrites: 0)
7056/7056
Hash status:
Size:    12500000 elements
Queries: 269667 (hits: 269667)
Entries: 7056 (overwrites: 0)

C:\GnuBg>makebearoff -t 6x4 -O 6_3_gnu_ts.bd -f gnubg_ts.bd
Two-sided database:
Number of points             :            6
Number of chequers           :            4
Calculate equities           : cubeless and cubeful
Write header                 : yes
Number of one-sided positions:          210
Total number of positions    :        44100
Size of resulting file       :       352800 bytes
Size of hash                 :    100000000 bytes
Reuse old bearoff database   : yes 6_3_gnu_ts.bd
Error initialising old bearoff database!
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Creating the one-sided database didn't generate the same error, but didn't 
appear to use the existing one. (See final line):
C:\GnuBg>makebearoff -o 3 -f gnubg_os.bd
One-sided database:
Number of points                  :            3
Number of chequers                :           15
Number of positions               :          816
Approximate by normal distribution: no
Include gammon distributions      : yes
Use compression scheme            : yes
Write header                      : yes
Size of cache                     :    100000000
Reuse old bearoff database        : no
Size of database (uncompressed)   :       104448
Estimated size of compressed db   :        26112
Hash status:
Size:    781250 elements
Queries: 0 (hits: 0)
Entries: 0 (overwrites: 0)
1:800/816
Hash status:
Size:    781250 elements
Queries: 33585 (hits: 33585)
Entries: 816 (overwrites: 0)

C:\GnuBg>makebearoff -o 4 -O gnubg_os.bd -f gnubg_os4.bd
One-sided database:
Number of points                  :            4
Number of chequers                :           15
Number of positions               :         3876
Approximate by normal distribution: no
Include gammon distributions      : yes
Use compression scheme            : yes
Write header                      : yes
Size of cache                     :    100000000
Reuse old bearoff database        : yes gnubg_os.bd
Size of database (uncompressed)   :       496128
Estimated size of compressed db   :       124032
Hash status:
Size:    781250 elements
Queries: 0 (hits: 0)
Entries: 0 (overwrites: 0)
1:3800/3876
Hash status:
Size:    781250 elements
Queries: 226632 (hits: 226632)
Entries: 3876 (overwrites: 0)
Number of reads in old database: 0
                                 ^
Look: ===========================^

--Ian