Computer chess analysis

"I want to see what it looks like to analyze a game with a program."

Really, you need no new software to do this. Just use the existing "play against machine feature" to accomplish this task.

For each move, feed the game position into crafty on level 8 and get crafty's move. Then, compare it to the players move.

If the move is not the same, state crafty's move.

You can set up a queue to analyse games after they are finished, or analyse each move after it is made. In each of these cases you could store the results into your database.

Also, since english hates repetition, you could use a dictionary of alternating phrases for good and bad moves.

@Mephostophilis
I am sure that stockfish is much better, but you should ask yourself: How many people actually beat crafty on level 8 without using assistance? How much harder need it get? You should consider this before switching.

I've beaten Crafty on level 8 without using computer assistance several times.

Granted, the vast majority of my games with Crafty are losses.

But I agree that thibault doesn't need to upgrade engines necessarily. Crafty is already popular and open-source, and more than enough for most people to handle XD. Still, if we're talking about features like engine analysis while replaying your own games and calling processes externally, there are situations where it would be preferable to upgrade to Stockfish.

"Play against the machine" does not really accomplish the same thing because if Crafty replies with a different move than the one your opponent did, you lose control over replaying the game in Crafty because the position and the rest of the game is changed.

Cant believe I didnt read this topic earlier.

There are many different ways to analyze games via chess engines. And of course different programs do it different.

Chessbase for example allows you to
analyze in several ways (I personally like chessbase analysis most, while not perfect it is very good).

For example the chess program can analyze the position in a human like manner. The outcome will be in plain words (English), with the best move (or short variation) of moves right beside it.

Another more common method is a simple blunder check
with variations written near the moves from the game.
This displays the point differential between the two players
based on the engines analysis. Additionally it will display the best variation possible beside it.
How long this variation is depends on the strength of engine, how much seconds / move you give for the analysis, and other options.

Another program that analyzes games is Arena.
I believe what it does is save the moves and candidate moves in a file somewhere inside its own folders.

On FICS (I use BabasChess) there is an analyze feature.
It uses Crafty also and its fairly good. Well above Master level in most cases. (although programs like Stockfish will demolish Crafty).

It displays the point differential and spits out the best variation
(just a few moves usually).

I think if you play on FICS or any other website with these features you will get a good idea of how it works.

As for switching from Crafty to Stockfish or other program
I would not worry about it unless you are really bored Thib.

Awesome. Lots of options.

Personally I dislike the English text because I think it's biased; I'd rather just read the numbers and stats in UCI interfaces like Chessbase.

I completely understand that view point.
I personally think a combo of both is the best option.

However what Thib posted appears to be text description based
and I think thats more work than just spitting out the numbers.

I will post more shortly

yeah I'm not sure but I guess he wants to inline the analysis feature while going to Replay and Analyse to make reviewing our games more convenient, without having to copy pasta the PGN notation text and such.

A hybrid of English text and numbers can certainly be less confusing to some people than pure numbers alone, though, yeah. Depends how much they know XD

That's my new challenge with lichess: provide automatic game analysis for the players. Display the results in a comprehensive way, that help spotting errors and maybe getting better at chess.

Also it will help the mods greatly when detecting engine users.

I'm actually looking at integrating stockfish. Will keep you updated.

I was going to post screenshots of various analyze features
but its way to much work for each scenario.

Thib with analyze features there is a fair amount of different outputs that could be shown.

Lichess mostly has casual and beginner players.

How many players would know what -+ means or -1.32 or
?!. For me its quite simple but I definetly can see players being confused.

Here is my suggestion:

In the engine analysis output...
Have 1)Chess Punctuation, 2)A few moves to demonstrate the best option, 3)Points differential can be optional depending on your mood lol.

1)Chess Punctuations are the following:

1. Move evaluation symbols

   • 1.1 ??: Blunder
   • 1.2 ?: Mistake
   • 1.3 ?!: Dubious move
   • 1.4 !?: Interesting move
   • 1.5 !: Good move
   • 1.6 ?: Brilliant move

2. Position evaluation symbols

   • 3.1 8: Unclear
   • 3.2 =/8: With compensation
   • 3.3 =: Even position
   • 3.4 +/= (=/+): Slight advantage
   • 3.5 +/- (-/+): Advantage
   • 3.6 +- (-+): Decisive advantage