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How is lichess able to analyse a game so fast

I am using game analysis feature and it is blazingly fast. In a matter of 30 seconds I get the analysis of 60 moves.

With how many plies is it analyzing a game? Is it possible to make a deeper analysis?
It analyses each position for 2.5 seconds on a single core with various clock speeds (but I think that they're all pretty high speed CPUs).

This is performed in parallel across several servers (each server gets a position to analyse) so the time it takes to produce an analysis is incredibly low.

The primary function of the computer analysis on lichess is you give you a rough idea of your performance, and point out any obvious mistakes. It's not really intended for more nuanced positions.

If you want to get deeper analysis, you'll have to download the PGN from lichess and install an engine on your computer. There's lots of decent options out there.
Thank you for super fast reply. Are you one of the developers? The paralleled part was not really obvious to me. I am also curious are there any posts here about how Stockfish was connected to a webserver.
Kinda sorta a developer. More like a moderator and designer.

The way stockfish interacts with the main server and all the rest of it is pretty technical and beyond the scope of my knowledge. I think you'd have to go digging through the source code for that info.
The source code for lichess is here: github.com/ornicar/lila

The technicalities are, well, technical, but sliiightly modified implementation of Stockfish 5 is used which is compatible for web purposes as well as for chess variants like King of The Hill that vanilla Stockfish doesn't support. If you're keen on further details, the #lichess IRC channel on Freenode is open to all your queries :)

PS: If you have a specific question about lichess in future, use the Q&A section here so as to benefit everyone and prevent duplicate questions http://en.lichess.org/qa :)

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