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Questions tagged [engines]

An engine is any machine or computer program that plays chess.

4
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1answer
164 views

Chess environments for reinforcement learning

I want to try some reinforcement learning techniques (borrowed from AlphaZero, etc.) and so I need a chess environment in order to run games. I code in python, so I found python-chess but ...
3
votes
1answer
92 views

What is %eval syntax in PGN

I've seen two formats of [%eval] syntax in PGN: [%eval 250,5] meaning white is +2.5 pawn up at depth 5 [%eval +0.25] means white is 0.25 pawn up Is any of those mentioned by some PGN standard? Which ...
3
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1answer
658 views

What is Alpha Zero's Play Style? (Including its Openings and its Middlegame) [closed]

If you want to read about its opening strategy, it is down below the link. If you want to read about its middlegame strategy or basic play style, it is at the top I want to know how I can play more ...
4
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3answers
192 views

Minimax and alpha beta

I want to implement a simple chess bot so I have been reading about this algorithm a lot. I can say I understand the basic idea of the algorithm but I can't clearly see how am I supposed to apply it ...
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0answers
59 views

Why don’t bots always play the same moves? [duplicate]

Stockfish recently played AlphaZero in an 100 game match. AlphaZero won 28 of them and the rest were drawn. Surely since chess engines always assess any given situation in the same manner they should ...
3
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1answer
104 views

What kind of hand-crafted features do top performing family of engines use to evaluate a position?

AlphaZero paper which introduced the engine which allegidly outperformed stockfish mentioned the following: These programs evaluate positions using features handcrafted by human grandmasters and ...
0
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1answer
74 views

convert stockfish pv output to show piece names [duplicate]

What are suggested coding snippets to add pieces to pure algebraic notation (this would change g1f3 to Nf3) when using the chess.js and chessboard.js (javascript) interface. Stockfish uses this type ...
1
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2answers
144 views

Why continue to increase search depth after mate is found?

Playing with test sets, several times I come across a behavior of the chess engines which I can't understand: Let's say I have the endgame [FEN "8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - - 0 1"] which after ...
5
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2answers
2k views

Chess GUI that allows null-moves

Is there a GUI that allows null-moves as legal moves? Of course for engines the null-move heuristic already is an established technique.
5
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3answers
368 views

How can minimax chess engines do alpha-beta pruning without reaching the final positions?

In order to calculate far ahead, minimax chess engines must perform alpha-beta pruning, where they don't calculate positions that are obviously winning or obviously losing. Without doing pruning, ...
6
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6answers
385 views

Is it wise to resign a game if the win is only apparent too many moves ahead?

I will clarify my question with an example: A grandmaster plays a game against stockfish, with a material handicap for stockfish, and the advantage is not clear for either of the players. Throughout ...
7
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2answers
306 views

How do chess engines evaluate a position if the position is in the middle of an exchange?

In the minimax algorithm, chess engines do a depth-first search as far as they can calculate ahead, and then evaluate all these final positions. Then, using these evaluations they work backwards one ...
5
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4answers
613 views

Do the new chess AIs play gambits?

Do the new chess AIs, such as Alpha Zero and Leela Zero, play gambits? By gambit, I do not mean a merely nominal gambit like the mainline Queen's Gambit, but rather a genuinely speculative offer of ...
0
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0answers
61 views

Two engines match from a given position

I use Fritz 15, which allows the following options: You can let play two engines against each other a normal game. You can setup a position and let one engine play out the position. What I would like ...
2
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1answer
244 views

How to make Lichess local analysis utilize more cpu and memory? [closed]

I get around x12 faster evaluation when I run Stockfish myself, so I checked my utilization when running local analysis (Chromium and Firefox) and saw that it just utilizes one thread and few ...
5
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1answer
103 views

alpha-beta algorithm returns a value between alpha and beta inclusive?

I am coding up a chess engine and using the alpha-beta algorithm for tree scanning. I ended up doing what they posted here: int alphabeta(int depth, int alpha, int beta) { move bestmove; if (...
8
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3answers
248 views

Chess engine with danger (mate) warnings for beginners?

I am new to the site and would appreciate help in this area. At my current stage (beginner) I have started to draw or sometimes even beat the computer at low levels (ex. chess.com level1,2,3, lichess....
4
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1answer
165 views

Output whether the best move is “much better” or only “slightly better” than the other moves

On Oct 31, 2014, Tord Romstad wrote: The moves are not searched in descending order from best to worst. Stockfish has no idea which move is the second, third best, etc., and it doesn't have any ...
3
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3answers
1k views

What is the Elo rating of Stockfish version that played AlphaZero?

AlphaZero has defeated Stockfish with all novelties and brilliant strategic sacrifices. But some people were disputing its win, because Stockfish was running on weak hardware (1 GB RAM), not access to ...
2
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3answers
358 views

Engine evaluating changing after making move suggested by engine

I've noticed that the engine (Stockfish 9) evaluates positions as significantly better for white if the evaluation is performed while white is on the move. The difference is sometimes more than half a ...
7
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1answer
177 views

In the Dubois-Steinitz match (1862), at what point does the match become irreversibly lost for White? And why does the engine not pick it up early?

I am a beginner player (~1400 rating on lichess). I was studying a famous match between Dubois and Steinitz shown below (analysis done by Stockfish on lichess.org). My doubts are: 1) At what move ...
4
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2answers
615 views

The principal variation is always wrong!

I read in an internet blog that when analyzing my games with an engine, it is often useless to copy the principal variation to my annotations, because (they say) it is well known that the principal ...
1
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2answers
127 views

Why do we increase depth of search for a mate detection in alpha beta pruning?

I was following a tutorial for making a chess engine and in that, while writing the alpha beta pruning function the tutorial before checking for all possible moves generated , checks weather the ...
5
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1answer
255 views

Do chess engines really prune more than 90% of branches?

I was looking at Fritz Online (https://fritz.chessbase.com/) engine's parameters/performance. Here is screen relating to one of made moves. It means that there was a general depth equals to 15 but ...
3
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5answers
339 views

Custom Chess (game) engine

Is there a chess engine which you can use regardless of the game's rules? For example I wanna create my own chess version in which queen will also be able to move as knight or just a 10x10-square ...
1
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2answers
125 views

I wanted to understand the chess engine comparison. What does this result matrix show?

For example in the first row and second column, Stockfish vs Houdini, the result is 27-25+7-3=-16. I understand that 27 signifies Stockfish's number of wins+ draws, similarly 25 signifies that of ...
2
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1answer
140 views

Is it possible to get DTM of a position from sygyzy tables?

This is a programming question related to chess endgame tables. As far as I know syzygy tables allow me to get WDL and DTZ information for a given position. Is it possible to somehow (without access ...
0
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2answers
105 views

Could chess puzzles change with the introduction of stronger engines?

Something I've noticed is even older chess puzzles never seem to age, somehow they even seem more masterful and demanding then the puzzles created today, but what if the solution for a puzzle is ...
2
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2answers
145 views

How Do Top Engines' Achieve Large Search Depth

Im new to programming chess engines. I have implemented a transposition table, search tree, and alpha-beta pruning, an can analyze ~80000 boards per second. However, even with alpha-beta search, when ...
0
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3answers
247 views

Why doing the Engine suggested move worsen my position?

It is going from #26 through +60 to +9. Thats all engines best moves with deep analysis. Schould it not be a forced checkmate if I will follow the engine evaluation?
0
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1answer
355 views

How do engines evaluate a position (actual algorithm)? [duplicate]

How do chess engines actually evaluate a position? I am looking for a technical answer, not a general summary of how minimax works, I already know how minimax and alpha-beta, etc, work, so please do ...
0
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0answers
26 views

How is the chess engine loaded into GUI? [duplicate]

Can I load my chess engine into a GUI while it's in the development process so things like debugging are easier ? If so, How and what are the difference between the different GUI Protocols ? Thanks ...
0
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1answer
224 views

Connecting UCI engine with iOS? [closed]

So I'm not actually making a Chess app, but I am trying to hook up an engine that uses a protocol almost exactly the same as UCI. I can get it working quite easily on a macOS app. Now, the hard part ...
1
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1answer
130 views

Engine recommends a move that (I think) loses a pawn

[FEN "rn2kbnr/ppp1pppp/8/3q4/3P4/8/PP2PPPP/1RBQKBNR w Kkq - 0 5"] If white doesn't play Ra1 then black can play Qxa2. But the engine says this is an inaccuracy, and that the best line is e2-e3.
1
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1answer
125 views

Tips for debugging and progressing a chess engine's implementation

As I mentioned in previous questions I'm currently following this tutorial for building my chess engine. The code was written in C#, but mine is in C++ and I'm in the phase of finalizing the board / ...
8
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2answers
421 views

Three Pawns for a Knight - Why Doesn't Stockfish Like it?

In a recent game I swapped off a knight for 3 pawns: [Event "County Match"] [Site "Deepest Darkest Southern England"] [Date "2018.01.20"] [White "English Player"] [Black "Ian Bush"] [Result "0-1"] [...
2
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1answer
202 views

Human–machine stronger than machine?

It seems to be pretty well established since the days of (the second) Deep Blue vs. Kasparov match that top machines can beat top humans at playing chess. However, Kasparov seems to claim that the ...
2
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2answers
252 views

Is it possible for stockfish to tell that mate is in X moves, when mate is in X + Y moves?

I know that it is possible for a chess engine to evaluate a position as mate in X moves, when in fact there exist a mate in smaller number of moves. But can the reverse situation happen? For example ...
1
vote
1answer
77 views

Notes on Chess Piece Class

I have following this tutorial http://www.chessbin.com/post/Chess-Piece-Representation to build simple chess engine right now . at the very first step of Chess Piece Class there are many things ...
0
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0answers
48 views

What is Chess Endianess? [duplicate]

What are those techniques to represent the board into chess program and What is the difference between them ? Little - Endian Least Significant Rank . Little - Endian Least Significant File . Big - ...
3
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2answers
150 views

What's is the Least significant File and Least Significant Rank?

I'm Reading this tutorial and there are 2 definitions that confuse me : https://chessprogramming.wikispaces.com/Square+Mapping+Considerations What's is the Least significant File and Least ...
4
votes
1answer
525 views

Is Deep Blue outdated?

I bought a laptop, a Dell, model XPS 13. I found a technical review which mentioned the Fritz test: Fritz is a chess benchmark that tests the computing capabilities of the CPU with various chess ...
5
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2answers
339 views

Losers Chess variant engine

Is there a strong Losers chess variant engine? I had a look at stockfish, but it doesn't support Losers chess, seemingly. (to be used on a Linux platform)
7
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2answers
378 views

How does an engine decide which node to search first?

This is a follow-up question to Randomness in Engine Play. SmallChess's answer indicates that in one instance, Stockfish searched a given number of nodes after 20s, and a different number in the other ...
0
votes
1answer
202 views

How the engine can detect the 3-fold repetition using FEN input? [duplicate]

When I run the engine (UCI interface), I usually feed the last position from the game using position fen ... command and get the best move back. The FEN encodes the possibility of the castlings, en-...
10
votes
2answers
590 views

Randomness in engine play

If I get two engines to play against each other with the same colours, will the same game result every time? If not, where does the randomness in engine play come from? (Neglecting the opening book, ...
0
votes
1answer
462 views

How to play against an engine using scid for a particular level?

The best free chess program SCID vs Pc is installed and the latest chess engines are installed. After watching video Jeremy Silman, to play for first low level then intermediate and then Master level. ...
8
votes
1answer
658 views

What was the source of randomness in the Alpha Zero vs Stockfish match?

My understanding is that Alpha Zero's algorithm was fixed after the "learning" phase, so would it come up with the same move for every position? Was the variability in the match entirely due to a ...
8
votes
1answer
945 views

Did Stockfish have access to an opening book in its games against AlphaZero?

I have seen some commentary that implies that Stockfish did not have access to an opening book in its much-reported match with AlphaZero, but I cannot find a conclusive citation, and my inability to ...
21
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7answers
10k views

Hardware used in AlphaZero vs Stockfish match

I understand that AlphaZero has to use a different kind of hardware than regular Stockfish. I would expect that the hardware has a large effect on engine strength. That's why I wonder whether there ...