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Posted: **Fri May 04, 2018 6:48 am**

I'm discovering to quad-board structure on chessprogrammingwiki : is it faster than regular bitboards ? Is there any perft benchmark somewhere to compare engines using different structures ?

Posted: **Fri May 04, 2018 8:24 am**

I use Quad-board, is very fast.
(in fact, I use Penta-board)

Posted: **Fri May 04, 2018 8:52 am**

I don't have data on quad-bitboard versus octa-bitboard, but quad-bitboard engines require a monochrome board representation, and my own testing does show that those are slightly slower than double colour board representations.

I can provide more accurate data in a few hours.

Posted: **Fri May 04, 2018 9:21 am**

What is your penta-board representation ? What is the 5th board used for ?

Posted: **Fri May 04, 2018 9:22 am**

Thanks Matthew, waiting for your data

Posted: **Fri May 04, 2018 10:06 am**

j_romang wrote:What is your penta-board representation ? What is the 5th board used for ?

Code: Select all

typedef struct
&#123;
    U64 a;  // &#1084;&#1072;&#1089;&#1082;&#1072; &#1072;&#1083;&#1100;&#1092;&#1072;-&#1092;&#1080;&#1075;&#1091;&#1088;
    U64 b;  // &#1084;&#1072;&#1089;&#1082;&#1072; b
    U64 c;  // &#1084;&#1072;&#1089;&#1082;&#1072; c
    U64 d;  // &#1084;&#1072;&#1089;&#1082;&#1072; d

    U16 k;  // 0&#1093;10110000 00110000 (&#1094;&#1074;&#1077;&#1090;, &#1088;&#1086;&#1082;&#1080;&#1088;&#1086;&#1074;&#1082;&#1080;, &#1082;&#1086;&#1083;-&#1074;&#1086; &#1092;&#1080;&#1075;&#1091;&#1088;)
    U8 e;   // ep 0..7 &#1077;&#1089;&#1083;&#1080; &#1077;&#1089;&#1090;&#1100;, 8 &#1077;&#1089;&#1083;&#1080; &#1085;&#1077;&#1090;
    U8 t;   // &#1089;&#1095;&#1077;&#1090;&#1095;&#1080;&#1082; 50-&#1080; &#1093;&#1086;&#1076;&#1086;&#1074;
    U8 r;   // &#1087;&#1086;&#1074;&#1090;&#1086;&#1088; &#1087;&#1086;&#1079;&#1080;&#1094;&#1080;&#1080;
    U8 s;   // &#1089;&#1087;&#1077;&#1094;&#1080;&#1092;&#1080;&#1082;&#1072; &#1087;&#1088;&#1077;&#1076;&#1099;&#1076;&#1091;&#1097;&#1077;&#1075;&#1086; &#1093;&#1086;&#1076;&#1072;
    S16 m;  // &#1084;&#1072;&#1090;&#1077;&#1088;&#1080;&#1072;&#1083;
&#125; tpos;

Posted: **Fri May 04, 2018 11:41 am**

Thanks eugene ! Could you explain what you store in 'e', 's', and 'm' ? 'r' is a repetition counter, right ?

Posted: **Fri May 04, 2018 12:13 pm**

j_romang wrote:Thanks eugene ! Could you explain what you store in 'e', 's', and 'm' ? 'r' is a repetition counter, right ?

k - color, castling, number of pieces
e - EP
t - the counter of 50 move rule
r - repeat position
s - specifics of the previous move
m - material

Posted: **Mon May 07, 2018 10:12 pm**

This got sidetracked by the forum migration and me getting ill over the weekend.

So, I ran a Perft benchmark (which admittedly isn't the whole story of a search, but it magnifies the important part).

It turns out that a monochrome move generator is slightly faster:

Code: Select all

AMD FX-6300 @ 3.5GHz: 
Double-colour:
CPW [637,032,715 nodes]:
real    1m16.190s
user    1m15.781s
sys     0m0.063s

Hartmann [4,782,906,132 nodes]:
real    10m9.788s
user    10m6.125s
sys     0m0.141s

Single-colour:
CPW:
real    1m15.089s
user    1m14.719s
sys     0m0.016s

Hartmann:
real    9m44.185s
user    9m40.984s
sys     0m0.188s

However, as a counterpoint:

Code: Select all

RPi 3B+ @ 1.4GHz:
Double-colour CPW:
real    6m14.229s
user    6m13.821s
sys     0m0.026s

Single-colour CPW:
real    8m24.195s
user    8m23.984s
sys     0m0.055s

So it's rather hardware dependent.

Posted: **Tue May 08, 2018 6:19 pm**

Thanks ! Is your raspberry Pi B+ running in 32 or 64 bit mode ?

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