Questions tagged [bitboard]
For questions about bitboards and using bitboards
29
questions
2
votes
1
answer
57
views
Issue with Magic Bitboards
I have a implemented a similar version to the example given on the chess programming wiki by Tord Romstad.
I just changed the random generation and stored the magics in an array. I even kept the old ...
- 91
2
votes
2
answers
94
views
Why consider all possible combinations of empty/occupied square a sliding piece can move to in attack table generation?
When generating attack tables for a rook, why do we consider all 2^(number of set bits on the mask) potential configurations of empty or occupied squares along the ranks and files where a rook can ...
- 21
0
votes
0
answers
68
views
Difficulty with magic bitboards
I am having some difficulty with magic bitboards, in that multiple blocker bitboards which would result in different attack boards having the same index. I realize this is likely because of one of the ...
- 1
-1
votes
1
answer
63
views
Storing generated moves for a chess engine in Java [closed]
I am in the process of building a chess engine in Java using bitboards. I know C/C++ is more optimal for this but I have no knowledge of either so I'd rather attempt to do it with Java for now. I have ...
2
votes
2
answers
220
views
Border pieces in Magic Bitboards
I've been trying to understand magic bitboards, but everywhere I've read failed to explain how edge pieces are handled.
The pieces at the borders are ignored to save space.
So for a bishop at D3, the ...
- 23
4
votes
1
answer
727
views
How do Chess Bitboards generate individual moves?
If I have a pawn bitboard like this, for example,
00000000
00000000
00000000
00000000
00001000
00000001
11110110
00000000
generating all of the, say, legal capture moves to the right will perform a ...
- 388
2
votes
1
answer
619
views
Bitboard chess engine design
What are the best approaches to designing a chess engine? What classes/structures should it have? How are they connected to each other? I'm building a chess engine but I often find myself overwhelmed. ...
- 103
4
votes
1
answer
497
views
Move generation for sliding pieces and Hyperbola Quintessence
I'm working on a bitboard-based chess engine at the moment and I have managed to generate pseudo-legal moves for knights, kings and pawns. However, I'm still trying to wrap my head around sliding ...
- 103
0
votes
1
answer
171
views
Search function for chess engines
I'm creating a bitboard based chess engine in c++ and I'm trying to write the search function. It currently looks something like this
double search(Position& pos, int depth, double alpha, double ...
- 171
1
vote
1
answer
319
views
Evaluation function in a bitboard based chess engine
How do you go about writing an evaluation function for a bitboard bases chess engine? I want to start of simple and only evaluate based on piece value, and where the pieces stand. For example a knight ...
- 171
1
vote
1
answer
375
views
Bitboards and sliding piece attacks
I have been searching about bit boards and piece attacks. The concept of using a bitwise and to find the set of attacked pieces (ie: knightAttackSet & opponentPieces) is really elegant and ...
- 113
2
votes
1
answer
637
views
Fastest way to parse a bitboard
I am making a chess engine, and for now I’m working on the move generation. I’m using bitboards, and so for example my magic bit boards file for a knight on d4 is
00000000
00000000
00101000
01000100
...
- 123
4
votes
1
answer
1k
views
How do I complete this implementation of magic bitboards?
I'm currently coding a chess engine in C++, and have run into a bit of trouble with my magic bitboard implementation.
So far, I have a function that calculates blockerBoards (all the possible pieces ...
- 43
2
votes
1
answer
319
views
How can I convert a possible pieces' moves to an actual move in a bitboard?
If I have a bitboard (e.g. for knight squares he can move to) like this:
00000000
00000000
00000000
00000000
00000000
01000000
00100000
N0000000
How can I "convert" it into a move or "...
- 21
1
vote
1
answer
255
views
How do I find bitboard attack maps non-manually?
I am writing a C++ chess engine based on the magic bitboard, where ordering for bitboards is from LSB to MSB in Little-Endian Rank-File mapping. I'd like to have a 6x64 dimension 2D array for all ...
- 13
1
vote
3
answers
771
views
Fastest way to generate castling moves in a computer chess engine
I am currently developing a Bitboard chess engine using C++. I am in the process of creating the move generator function. I have completed most of it and only the casting part is left.
I have used ...
user24649
3
votes
1
answer
163
views
How do I apply moves (bitboard) and continue searching? My current attempt is throwing a strange error!
Explanation
I have a list of all possible current moves in a position. At each node, I want to then generate all possible moves and continue. The problem is that my code is modifying the list of moves ...
1
vote
1
answer
347
views
How to store moves for a magic bitboard system?
I am currently trying to implement magic bitboards into my chess engine. Let's just talk about rooks here. Given a square, what I can currently do is:
-Calculate the sliding moves on an empty board.
...
4
votes
2
answers
3k
views
Quickly converting board to bitboard representation using python-chess library
I would like to convert a given chess board into its bitboard representation, but my implementation is rather slow. Here is what I'm doing (using the python-chess package):
board = chess.Board('...
- 171
3
votes
1
answer
415
views
Magic Bitboards, Feeding in Randoms - Why have to find magic instead of just loading from disk?
I read about Looking for Magics for Magic Bitboard, they mentioned the method "Feeding in Randoms".
As I understand, this method works like this:
label RETRY;
magic = random();//trial
for (all ...
- 181
5
votes
1
answer
535
views
Are these magics wrong?
I am working on my chess engine and wanted to finally implement magic bitboards to get a huge increase in performance.
Basically I was writing a method to check if a number can be used as a magic for ...
- 340
2
votes
1
answer
245
views
Can engines use the current pawn structure to refine its search/eval?
As I understand it, engines use so-called "bitboards" to generate the current position & possible moves. I'm wondering if any engine uses the pawn bitboard to refine its search and eval.
To ...
- 26.1k
5
votes
2
answers
940
views
Chess Engine: Generate a Bitboard of Pinned Pieces
I'm currently working on a chess engine and have a pseudo-legal move generator working. I'm looking for a way to efficiently generate a bitboard of pinned pieces, so I could skip them when generating ...
- 141
5
votes
3
answers
5k
views
What's the right approach of storing moves generated using bitboards?
I am building a chess engine from scratch using bitboards and, so far I am able to generate pawns moves. But, I am stuck on what should I do after finding all possible moves for pawns.
Right now the ...
- 171
1
vote
1
answer
3k
views
Understanding magic bitboard
I have read a lot of stuff about magic bitboard but some stuff is not clear. A lot of authors say to create the move masks for the piece avoiding the border positions. So, for a bishop at D3 the move ...
- 161
4
votes
2
answers
2k
views
Building a chess using magic bitboard... how do I know if the movement is valid
OK I have read a lot of things on the web most of them using Java that doesn't have unsigned int. I am working on Objective-C that has unsigned int.
Lets consider the following scenario.
The board ...
- 161
7
votes
3
answers
6k
views
Representing Moves found via BitBoards, applying them, and removing them
I understand how to find all valid moves for all pieces on the board. For example I know that a certain knight can hit all of the 1's in this board
01000000
00100000
N0000000
00100000
01000000
...
- 449
9
votes
1
answer
3k
views
Find magic numbers for bitboards
I am writing a C++ chess engine and I am looking for magic numbers for Little-Endian Rank-File Mapping bitboards to generate moves for sliding pieces.
The rival chess website gives magic numbers but ...
- 667
12
votes
2
answers
19k
views
How to represent chess state with a bitboard
I'm interested in programming a chess engine and using bitboards to represent the state of the game. I know there are a few open source chess engines that use bitboards, but its not so easy to look at ...
- 383