Search found 142 matches

by Fulvio
Wed Mar 27, 2019 5:21 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: No bishop magics with fixed shift 8
Replies: 17
Views: 3286

Re: No bishop magics with fixed shift 8

Some futher considerations, I hope the math is correct. For a bishop in C1, let's define: bitboard_D2 = 1 << 11; bitboard_E3 = 1 << 20; bitboard_D2_E3 = bitboard_D2 + bitboard_E3; If we search for a 4 bits hash, we know that: idx_bitboard_D2 > 0 && idx_bitboard_D2 < 16 idx_bitboard_E3 > 0 && idx_bit...
by Fulvio
Tue Mar 26, 2019 8:54 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: No bishop magics with fixed shift 8
Replies: 17
Views: 3286

Re: No bishop magics with fixed shift 8

we have selected the smallest possible numbers for hash values which avoid collisions with previously chosen hash values. That's the problem. We know that collisions can be valid. Picking powers of 2 generates big gaps, so it is necessary to demonstrate that all those gaps are filled with invalid c...
by Fulvio
Mon Mar 25, 2019 7:43 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: No bishop magics with fixed shift 8
Replies: 17
Views: 3286

Re: No bishop magics with fixed shift 8

and now the minimum magic number is 0x40100c0a00000 If you try this as a magic number for the C1 square you will see that it does not work. Yes, it is not the minimum valid magic number, but it is a guaranteed lower bound; i.e. any smaller number cannot be a valid magic number. It also provides an ...
by Fulvio
Mon Mar 25, 2019 4:42 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: No bishop magics with fixed shift 8
Replies: 17
Views: 3286

Re: No bishop magics with fixed shift 8

I see, given a 64-bit magic number and a bitboard with only one square, we can divide it in 3 parts considering how it affects the index: the first (64 - n_hashbits - square - 1) bits are ignored, due to the right shift; the last (square) bits are ignored, due to the left shift; the bits in the midd...
by Fulvio
Sat Mar 23, 2019 9:41 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: No bishop magics with fixed shift 8
Replies: 17
Views: 3286

Re: No bishop magics with fixed shift 8

For instance, the square F6 (45) has a occupancy mask that includes the squares B2 (9), C3 (18), D4 (27), E5 (36), G5 (38), E7 (52), and G7 (54). Assuming we are looking for magics that have a right shift of 7, we can determine the minimum possible magic number as: 2^(64-7-9) + 2^(64-7-18+1) = 0x10...
by Fulvio
Fri Mar 15, 2019 10:06 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Further progress on new move generator
Replies: 28
Views: 3096

Re: Further progress on new move generator

Perft is a poor measure for engine move-generation speed anyway, for several reasons: * It emulates full-width search, while an engine is spending most of its time in QS. * It requires explicit checking of the moves for legality, while most engines just test for King capture in the daughter node * ...
by Fulvio
Fri Mar 15, 2019 9:58 am
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Further progress on new move generator
Replies: 28
Views: 3096

Re: Further progress on new move generator

In the example of 75 mln. nodes/sec you gave above you forgot to mention what kind of CPU you tested this on, this is not very useful either. That's why I posted the code, and I should have also posted how to compile it. After downloading the lc0 code from github and saving that code into lc0/src/c...
by Fulvio
Thu Mar 14, 2019 4:37 pm
Forum: Computer Chess Club: Programming and Technical Discussions
Topic: Further progress on new move generator
Replies: 28
Views: 3096

Re: Further progress on new move generator

And this is a strawman argument. You changed the argument from is one faster than the other to did you count nodes properly. Well, if both count nodes in the same way and the table lookup is faster, which I can also demonstrate, your argument is non sequitur. It is not my intention at all to sugges...
by Fulvio
Mon Feb 04, 2019 4:21 pm
Forum: Computer Chess Club: General Topics
Topic: SCID 4.7
Replies: 44
Views: 4860

Re: SCID 4.7

Another question: How can I create an epd file? When I click on New... I only get two options under "save as type", si4 and pgn, but the wiki says it's possible to create new epd files. At the moment it is not possible to create epd files. It is not a difficult feature to add, I only wonder what th...
by Fulvio
Mon Feb 04, 2019 4:14 pm
Forum: Computer Chess Club: General Topics
Topic: SCID 4.7
Replies: 44
Views: 4860

Re: SCID 4.7

I am going to download SCID for the first time today. I am wondering if this Shane person is still involved or who is in charge of SCID. No, the original author of SCID stopped working on it many yeas ago: https://sourceforge.net/p/scid/wiki/ShaneHudson/ I'm the one maintaining the project since 20...