OliThink 5.4.0 has been published with an big leap in strength for only 3 lines of code

[Dann Corbit]

I guess with shared hash and threads, about 3500 Elo{*].
i have 64 threads on my box.
[*] CCRL or CEGT scale

[Graham Banks]

I will be starting an OliThink gauntlet for CCRL 40/15 this week.
I was going to use 5.6.6, but I guess that I should now use 5.6.8 or later if you release again today?

[OliverBr]

I will be starting an OliThink gauntlet for CCRL 40/15 this week.
I was going to use 5.6.6, but I guess that I should now use 5.6.8 or later if you release again today?

Hi Graham,
Which OS are you using? Windows? I have just released a 5.6.8 using popcnt hardware support for Windows 64:
http://brausch.org/home/chess/OliThink568pop.win64.zip

I am looking forward for your tourney.

[Graham Banks]

I will be starting an OliThink gauntlet for CCRL 40/15 this week.
I was going to use 5.6.6, but I guess that I should now use 5.6.8 or later if you release again today?

Hi Graham,
Which OS are you using? Windows? I have just released a 5.6.8 using popcnt hardware support for Windows 64:
http://brausch.org/home/chess/OliThink568pop.win64.zip

Windows.
I'll use 5.6.8 unless there is a later one once I'm ready to start.

[OliverBr]

Windows.
I'll use 5.6.8 unless there is a later one once I'm ready to start.

I know, I am releasing a lot of versions nowadays, that's because I have a new toy, a 32-core test computer, so I could improve quite a bit. Anyway the 5.6.8 is good, a newer version is not expected very soon.

[OliverBr]

Windows.
I'll use 5.6.8 unless there is a later one once I'm ready to start.

I know, I am releasing a lot of versions nowadays, that's because I have a new toy, a 32-core test computer, so I could improve quite a bit. Anyway the 5.6.8 is good, a newer version is not expected very soon.

Hi Graham.. I actually found a little change which improves 5.6.8 another 20 ELO points.. So, yes another version (5.6.9) is coming soon.

Code: Select all

   # PLAYER             :  RATING  ERROR  POINTS  PLAYED   (%)     W     D     L  D(%)  CFS(%)
   1 OliThink 5.6.8b    :      22      9  2002.0    3765  53.2  1290  1424  1051  37.8     100
   2 OliThink 5.6.8a    :       0   ----  1763.0    3765  46.8  1051  1424  1290  37.8     ---

White advantage = 21.06 +/- 4.45
Draw rate (equal opponents) = 38.06 % +/- 0.79

[OliverBr]

5.6.9 has been released. It gains about 25 ELO to 5.6.8, thus OliThink finally has more than ELO 2600.

The trick was a revert of the following change in OliThink 5.1.7 from the year 2008:

5.1.6 has in line 1549:

Code: Select all

    for (i = 0; i < 64; i++) nmobil[i] = bitcnt(nmoves[i])*8;

5.1.7 has:

Code: Select all

    for (i = 0; i < 64; i++) nmobil[i] = (bitcnt(nmoves[i])-1)*6;

5.1.7 has been 25 ELO weaker than 5.1.6 after modification. I couldn't know those days, but now I found it out with a big tournament.
So in 5.6.9 I reverted it, again using a factor 8.



PS: Funny fact: When starting small tournaments with fast timecontrol and another engine like Fruit2.1, it always plays very strong at the beginning.
After about 100 games for each engine:

Code: Select all

   # PLAYER             :  RATING  ERROR  POINTS  PLAYED   (%)    W    D    L  D(%)  CFS(%)
   1 OliThink 5.6.9	:      70     69    50.5      90  56.1   34   33   23  36.7      68
   2 Fruit 2.1          :      54     65    47.5      90  52.8   33   29   28  32.2      95
   3 OliThink 5.6.8     :       0   ----    38.0      92  41.3   21   34   37  37.0     ---

White advantage = 10.54 +/- 25.14
Draw rate (equal opponents) = 35.92 % +/- 4.31

But with more games this is converging to the expected result:

Code: Select all

   # PLAYER             :  RATING  ERROR  POINTS  PLAYED   (%)    W    D    L  D(%)  CFS(%)
   1 Fruit 2.1          :      92     21   613.5    1008  60.9  518  191  299  18.9     100
   2 OliThink 5.6.9     :      28     21   478.5    1008  47.5  325  307  376  30.5     100
   3 OliThink 5.6.8     :       0   ----   420.0    1008  41.7  270  300  438  29.8     ---

White advantage = 28.64 +/- 7.94
Draw rate (equal opponents) = 27.16 % +/- 1.17

This is reproducible. What could be an explanation for this?

[Kieren Pearson]

5.6.9 has been released. It gains about 25 ELO to 5.6.8, thus OliThink finally has more than ELO 2600.

The trick was a revert of the following change in OliThink 5.1.7 from the year 2008:

5.1.6 has in line 1549:

Code: Select all

    for (i = 0; i < 64; i++) nmobil[i] = bitcnt(nmoves[i])*8;

5.1.7 has:

Code: Select all

    for (i = 0; i < 64; i++) nmobil[i] = (bitcnt(nmoves[i])-1)*6;

5.1.7 has been 25 ELO weaker than 5.1.6 after modification. I couldn't know those days, but now I found it out with a big tournament.
So in 5.6.9 I reverted it, again using a factor 8.



PS: Funny fact: When starting small tournaments with fast timecontrol and another engine like Fruit2.1, it always plays very strong at the beginning.
After about 100 games for each engine:

Code: Select all

   # PLAYER             :  RATING  ERROR  POINTS  PLAYED   (%)    W    D    L  D(%)  CFS(%)
   1 OliThink 5.6.9	:      70     69    50.5      90  56.1   34   33   23  36.7      68
   2 Fruit 2.1          :      54     65    47.5      90  52.8   33   29   28  32.2      95
   3 OliThink 5.6.8     :       0   ----    38.0      92  41.3   21   34   37  37.0     ---

White advantage = 10.54 +/- 25.14
Draw rate (equal opponents) = 35.92 % +/- 4.31

But with more games this is converging to the expected result:

Code: Select all

   # PLAYER             :  RATING  ERROR  POINTS  PLAYED   (%)    W    D    L  D(%)  CFS(%)
   1 Fruit 2.1          :      92     21   613.5    1008  60.9  518  191  299  18.9     100
   2 OliThink 5.6.9     :      28     21   478.5    1008  47.5  325  307  376  30.5     100
   3 OliThink 5.6.8     :       0   ----   420.0    1008  41.7  270  300  438  29.8     ---

White advantage = 28.64 +/- 7.94
Draw rate (equal opponents) = 27.16 % +/- 1.17

This is reproducible. What could be an explanation for this?

This is very strange. Does the GUI restart each engine after each match?

[OliverBr]

This is reproducible. What could be an explanation for this?

This is very strange. Does the GUI restart each engine after each match?

No, cutechess-cli is not restarting the engine. There is actually a parameter in the xboard protocol ("reuse") , it's the recommended "1", the engine will not restartet. Actually this should be standard.

I guess that Fruit is a good learner just alone by filling the Hash(TT)Tables. OliThink always replaces hash-entries, so they don't live very long.

After more 3000 games, there is +22 ELO, same as in the battle between the OliThinks

Code: Select all

   # PLAYER             :  RATING  ERROR  POINTS  PLAYED   (%)     W    D     L  D(%)  CFS(%)
   1 Fruit 2.1          :      91     12  1931.0    3156  61.2  1644  574   938  18.2     100
   2 OliThink 5.6.9    :      22     12  1474.5    3158  46.7  1015  919  1224  29.1     100
   3 OliThink 5.6.8     :       0   ----  1330.5    3158  42.1   868  925  1365  29.3     ---

White advantage = 28.37 +/- 4.38
Draw rate (equal opponents) = 26.28 % +/- 0.69

[Kieren Pearson]

I find it hard to believe that fruit is able to use transposition entries from different games to observe a noticeable increase in strength over time. There’s no way those entities are surviving that long and if they were future games should have had a different opening and the entires wouldn’t even be useful anyways.

Do you use an opening book for your tournaments?

Two more possibilities: It was just a coincidence that your engine did better for the first 100 games, or maybe your engine has a bug which causes it to have lowered nps over time. I say this because my engine had a similar bug early in its development.