[Bug-gnubg] bearoff databases (again!)

[Joern Thyssen]

Hi all,

I've made a few changes to the generation of two sided bearoff
databases.

Instead of storing intermediate results in floating point numbers
they're now stored as 2 byte integers. This has at least two advantages:

* the calculations will be faster (since most computeres perform integer
  arithmetics faster than floating point arithmetics)
* more positions can be stored in the memory while generating the
  database (the resulting file has the same size)

The drawback is that the new two-sided databases differ slightly from
the previous ones. The largest deviation I've seen is around 0.0002
measured in equity (the deviation is due to rounding errors).

I plan to publish MD5 checksums of the two-sided bearoff databases as I
generate them. However, if you're using two sided bearoff databases from
the previous version, you can't compare these MD5 checksums.

MD5 check sums for one-sided bearoff databases:

The table below contains the MD5 checksums for the compressed one sided
bearoff databases, i.e., databases generated with default options.

*Chequers*         *Points*           *MD5 checksum*
15                 1                  `c789f049ec98ce4e307b471257999f39'
15                 2                  `b6e61c1625ae4b3b164e93ab064192b9'
15                 3                  `346dae6139ccb4b227c534373e5c52e4'
15                 4                  `653255f5f9f22fd50277f7ff25b2a343'
15                 5                  `2064f9a56b23117d053a573c96a92fa2'
15                 6                  `3dc7b833c4670849cee00479a9e21b49'
15                 7                  `67235c8e0ee152df5daf36cbeae5b3c2'
15                 8                  `a4acbb5c7e9e1f08e561afe0af934e5c'
15                 9                  `9c4ddab4e51c3e668c9c97b8f8768dbc'
15                 10                 `81b3898f06bbd08ee8295a839251a10a'
15                 11                 `78ecb4be86dab6af8755ea4063d50fb6'

I'm generating the 12 point database right now. It's been running for 11
hours and is approximately half finished. I'll probably not go further
than this, although the 13pt database is a bit interesting as many races
starts by breaking contact on the midpoints.

The table below contains the MD5 checksums for the default two sided
bearoff databases.

*Chequers*         *Points*           *MD5 checksum*
1                  6                  `7ed6f8e7fce16ea2b80e07a4a516653c'
2                  6                  `e9d760bf213841c285245ed757a52f4d'
3                  6                  `9d67da3db32ad4720cc38eecf9a67967'
4                  6                  `9156f37032d1d4b0352a41186e632dfc'
5                  6                  `0db19ab08feae1feb33ddbd709479f62'
6                  6                  `44b6040b49b46cb9dd2ce8caa947044d'
7                  6                  `9eb8b042d4d2ddf8d40e74a892745ad5'
8                  6                  `fcdbbc80b7ef84ddc81b839d0f26bed1'

I'll generate the 9 chequer and 10 chequer databases as well. Possibly
also the 11 chequer database.

Jørn