perft test

Discussion of chess software programming and technical issues.

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giggetto71
Posts: 3
Joined: Tue Aug 31, 2021 8:33 am
Full name: Pierluigi Meloni

perft test

Post by giggetto71 »

Hi,
I need some guidance with respect to perft test (https://www.chessprogramming.org/Perft_Results).
I get perfect result up to perft(5).
When I run perft(6) I get 119059876 instead of 119060324 and I cannot find anything that could explain that. Apparently the moves generator is working ok, I mean if there were some issue shouldn't I get wrong numbers in perft(4) and perft(5) already? I notice that at perft(6) level discovery checks and double checks start appearing so I thought I had some issues there in the move gen but I checked manually many discovery and double and apparently everything looks fine. Can you recommend some testing I could do understand where that difference may come from?
thanks you very much.
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R. Tomasi
Posts: 307
Joined: Wed Sep 01, 2021 4:08 pm
Location: Germany
Full name: Roland Tomasi

Re: perft test

Post by R. Tomasi »

giggetto71 wrote: ↑Fri Sep 24, 2021 12:07 pm Hi,
I need some guidance with respect to perft test (https://www.chessprogramming.org/Perft_Results).
I get perfect result up to perft(5).
When I run perft(6) I get 119059876 instead of 119060324 and I cannot find anything that could explain that. Apparently the moves generator is working ok, I mean if there were some issue shouldn't I get wrong numbers in perft(4) and perft(5) already? I notice that at perft(6) level discovery checks and double checks start appearing so I thought I had some issues there in the move gen but I checked manually many discovery and double and apparently everything looks fine. Can you recommend some testing I could do understand where that difference may come from?
thanks you very much.
What really helps when debugging perft/move generation is to have a perft routine with divide, i.e. for every move in the root position prints the number of submoves. Like this:

Code: Select all

perft 3

  b1a3  : 400
  b1c3  : 440
  g1f3  : 440
  g1h3  : 400
  a2a3  : 380
  b2b3  : 420
  c2c3  : 420
  d2d3  : 539
  e2e3  : 599
  f2f3  : 380
  g2g3  : 420
  h2h3  : 380
  a2a4  : 420
  b2b4  : 421
  c2c4  : 441
  d2d4  : 560
  e2e4  : 600
  f2f4  : 401
  g2g4  : 421
  h2h4  : 420
You can then compare your results with the perft of other engines that also have divide. If for a move the numbers don't match, then make that move and redo a perft with depth reduced by 1. Eventually you will end up exactly at the move that is missing.
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mvanthoor
Posts: 1784
Joined: Wed Jul 03, 2019 4:42 pm
Location: Netherlands
Full name: Marcel Vanthoor

Re: perft test

Post by mvanthoor »

Not enough information...

Is your code viewable somewhere?
What position are you running perft on?
Did you implement a "divide perft", so you can compare move by move against a known-good engine or perft utility that can also do divide perft?
Author of Rustic, an engine written in Rust.
Releases | Code | Docs | Progress | CCRL
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dangi12012
Posts: 1062
Joined: Tue Apr 28, 2020 10:03 pm
Full name: Daniel Infuehr

Re: perft test

Post by dangi12012 »

Dont try the default fen - there are many - many - many bugs that are hidden until later positions. Deep bugs in movegen are having todo with pinned enpassant captures that may or may not be valid. Also castling when one of the castling squares is attacked is a very common bug.

Also think about pinned pawn promotion. And maybe if you are in check you still can do a promotion to avoid the check etc.

The best information I can give you is to use Juddperft Debug mode https://github.com/jniemann66/juddperft
with the text-external command. It will find the one position where you get a buggy behaviour.

Also here are some positions with the depths that I run before running anything to make sure my engine is working correctly:
Most if not all mistakes occure in there somewhere

Code: Select all

#pragma once
#include <string>
#include <vector>
#include <sstream>
#include <iostream>

namespace Test {
	std::string Positions[] =
	{
		std::string("rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 ;D1 20 ;D2 400 ;D3 8902 ;D4 197281 ;D5 4865609 ;D6 119060324"),
		std::string("r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1 ;D1 48 ;D2 2039 ;D3 97862 ;D4 4085603 ;D5 193690690"),
		std::string("4k3/8/8/8/8/8/8/4K2R w K - 0 1 ;D1 15 ;D2 66 ;D3 1197 ;D4 7059 ;D5 133987 ;D6 764643"),
		std::string("4k3/8/8/8/8/8/8/R3K3 w Q - 0 1 ;D1 16 ;D2 71 ;D3 1287 ;D4 7626 ;D5 145232 ;D6 846648"),
		std::string("4k2r/8/8/8/8/8/8/4K3 w k - 0 1 ;D1 5 ;D2 75 ;D3 459 ;D4 8290 ;D5 47635 ;D6 899442"),
		std::string("r3k3/8/8/8/8/8/8/4K3 w q - 0 1 ;D1 5 ;D2 80 ;D3 493 ;D4 8897 ;D5 52710 ;D6 1001523"),
		std::string("4k3/8/8/8/8/8/8/R3K2R w KQ - 0 1 ;D1 26 ;D2 112 ;D3 3189 ;D4 17945 ;D5 532933 ;D6 2788982"),
		std::string("r3k2r/8/8/8/8/8/8/4K3 w kq - 0 1 ;D1 5 ;D2 130 ;D3 782 ;D4 22180 ;D5 118882 ;D6 3517770"),
		std::string("8/8/8/8/8/8/6k1/4K2R w K - 0 1 ;D1 12 ;D2 38 ;D3 564 ;D4 2219 ;D5 37735 ;D6 185867"),
		std::string("8/8/8/8/8/8/1k6/R3K3 w Q - 0 1 ;D1 15 ;D2 65 ;D3 1018 ;D4 4573 ;D5 80619 ;D6 413018"),
		std::string("4k2r/6K1/8/8/8/8/8/8 w k - 0 1 ;D1 3 ;D2 32 ;D3 134 ;D4 2073 ;D5 10485 ;D6 179869"),
		std::string("r3k3/1K6/8/8/8/8/8/8 w q - 0 1 ;D1 4 ;D2 49 ;D3 243 ;D4 3991 ;D5 20780 ;D6 367724"),
		std::string("r3k2r/8/8/8/8/8/8/R3K2R w KQkq - 0 1 ;D1 26 ;D2 568 ;D3 13744 ;D4 314346 ;D5 7594526 ;D6 179862938"),
		std::string("r3k2r/8/8/8/8/8/8/1R2K2R w Kkq - 0 1 ;D1 25 ;D2 567 ;D3 14095 ;D4 328965 ;D5 8153719 ;D6 195629489"),
		std::string("r3k2r/8/8/8/8/8/8/2R1K2R w Kkq - 0 1 ;D1 25 ;D2 548 ;D3 13502 ;D4 312835 ;D5 7736373 ;D6 184411439"),
		std::string("r3k2r/8/8/8/8/8/8/R3K1R1 w Qkq - 0 1 ;D1 25 ;D2 547 ;D3 13579 ;D4 316214 ;D5 7878456 ;D6 189224276"),
		std::string("1r2k2r/8/8/8/8/8/8/R3K2R w KQk - 0 1 ;D1 26 ;D2 583 ;D3 14252 ;D4 334705 ;D5 8198901 ;D6 198328929"),
		std::string("2r1k2r/8/8/8/8/8/8/R3K2R w KQk - 0 1 ;D1 25 ;D2 560 ;D3 13592 ;D4 317324 ;D5 7710115 ;D6 185959088"),
		std::string("r3k1r1/8/8/8/8/8/8/R3K2R w KQq - 0 1 ;D1 25 ;D2 560 ;D3 13607 ;D4 320792 ;D5 7848606 ;D6 190755813"),
		std::string("4k3/8/8/8/8/8/8/4K2R b K - 0 1 ;D1 5 ;D2 75 ;D3 459 ;D4 8290 ;D5 47635 ;D6 899442"),
		std::string("4k3/8/8/8/8/8/8/R3K3 b Q - 0 1 ;D1 5 ;D2 80 ;D3 493 ;D4 8897 ;D5 52710 ;D6 1001523"),
		std::string("4k2r/8/8/8/8/8/8/4K3 b k - 0 1 ;D1 15 ;D2 66 ;D3 1197 ;D4 7059 ;D5 133987 ;D6 764643"),
		std::string("r3k3/8/8/8/8/8/8/4K3 b q - 0 1 ;D1 16 ;D2 71 ;D3 1287 ;D4 7626 ;D5 145232 ;D6 846648"),
		std::string("4k3/8/8/8/8/8/8/R3K2R b KQ - 0 1 ;D1 5 ;D2 130 ;D3 782 ;D4 22180 ;D5 118882 ;D6 3517770"),
		std::string("r3k2r/8/8/8/8/8/8/4K3 b kq - 0 1 ;D1 26 ;D2 112 ;D3 3189 ;D4 17945 ;D5 532933 ;D6 2788982"),
		std::string("8/8/8/8/8/8/6k1/4K2R b K - 0 1 ;D1 3 ;D2 32 ;D3 134 ;D4 2073 ;D5 10485 ;D6 179869"),
		std::string("8/8/8/8/8/8/1k6/R3K3 b Q - 0 1 ;D1 4 ;D2 49 ;D3 243 ;D4 3991 ;D5 20780 ;D6 367724"),
		std::string("4k2r/6K1/8/8/8/8/8/8 b k - 0 1 ;D1 12 ;D2 38 ;D3 564 ;D4 2219 ;D5 37735 ;D6 185867"),
		std::string("r3k3/1K6/8/8/8/8/8/8 b q - 0 1 ;D1 15 ;D2 65 ;D3 1018 ;D4 4573 ;D5 80619 ;D6 413018"),
		std::string("r3k2r/8/8/8/8/8/8/R3K2R b KQkq - 0 1 ;D1 26 ;D2 568 ;D3 13744 ;D4 314346 ;D5 7594526 ;D6 179862938"),
		std::string("r3k2r/8/8/8/8/8/8/1R2K2R b Kkq - 0 1 ;D1 26 ;D2 583 ;D3 14252 ;D4 334705 ;D5 8198901 ;D6 198328929"),
		std::string("r3k2r/8/8/8/8/8/8/2R1K2R b Kkq - 0 1 ;D1 25 ;D2 560 ;D3 13592 ;D4 317324 ;D5 7710115 ;D6 185959088"),
		std::string("r3k2r/8/8/8/8/8/8/R3K1R1 b Qkq - 0 1 ;D1 25 ;D2 560 ;D3 13607 ;D4 320792 ;D5 7848606 ;D6 190755813"),
		std::string("1r2k2r/8/8/8/8/8/8/R3K2R b KQk - 0 1 ;D1 25 ;D2 567 ;D3 14095 ;D4 328965 ;D5 8153719 ;D6 195629489"),
		std::string("2r1k2r/8/8/8/8/8/8/R3K2R b KQk - 0 1 ;D1 25 ;D2 548 ;D3 13502 ;D4 312835 ;D5 7736373 ;D6 184411439"),
		std::string("r3k1r1/8/8/8/8/8/8/R3K2R b KQq - 0 1 ;D1 25 ;D2 547 ;D3 13579 ;D4 316214 ;D5 7878456 ;D6 189224276"),
		std::string("8/1n4N1/2k5/8/8/5K2/1N4n1/8 w - - 0 1 ;D1 14 ;D2 195 ;D3 2760 ;D4 38675 ;D5 570726 ;D6 8107539"),
		std::string("8/1k6/8/5N2/8/4n3/8/2K5 w - - 0 1 ;D1 11 ;D2 156 ;D3 1636 ;D4 20534 ;D5 223507 ;D6 2594412"),
		std::string("8/8/4k3/3Nn3/3nN3/4K3/8/8 w - - 0 1 ;D1 19 ;D2 289 ;D3 4442 ;D4 73584 ;D5 1198299 ;D6 19870403"),
		std::string("K7/8/2n5/1n6/8/8/8/k6N w - - 0 1 ;D1 3 ;D2 51 ;D3 345 ;D4 5301 ;D5 38348 ;D6 588695"),
		std::string("k7/8/2N5/1N6/8/8/8/K6n w - - 0 1 ;D1 17 ;D2 54 ;D3 835 ;D4 5910 ;D5 92250 ;D6 688780"),
		std::string("8/1n4N1/2k5/8/8/5K2/1N4n1/8 b - - 0 1 ;D1 15 ;D2 193 ;D3 2816 ;D4 40039 ;D5 582642 ;D6 8503277"),
		std::string("8/1k6/8/5N2/8/4n3/8/2K5 b - - 0 1 ;D1 16 ;D2 180 ;D3 2290 ;D4 24640 ;D5 288141 ;D6 3147566"),
		std::string("8/8/3K4/3Nn3/3nN3/4k3/8/8 b - - 0 1 ;D1 4 ;D2 68 ;D3 1118 ;D4 16199 ;D5 281190 ;D6 4405103"),
		std::string("K7/8/2n5/1n6/8/8/8/k6N b - - 0 1 ;D1 17 ;D2 54 ;D3 835 ;D4 5910 ;D5 92250 ;D6 688780"),
		std::string("k7/8/2N5/1N6/8/8/8/K6n b - - 0 1 ;D1 3 ;D2 51 ;D3 345 ;D4 5301 ;D5 38348 ;D6 588695"),
		std::string("B6b/8/8/8/2K5/4k3/8/b6B w - - 0 1 ;D1 17 ;D2 278 ;D3 4607 ;D4 76778 ;D5 1320507 ;D6 22823890"),
		std::string("8/8/1B6/7b/7k/8/2B1b3/7K w - - 0 1 ;D1 21 ;D2 316 ;D3 5744 ;D4 93338 ;D5 1713368 ;D6 28861171"),
		std::string("k7/B7/1B6/1B6/8/8/8/K6b w - - 0 1 ;D1 21 ;D2 144 ;D3 3242 ;D4 32955 ;D5 787524 ;D6 7881673"),
		std::string("K7/b7/1b6/1b6/8/8/8/k6B w - - 0 1 ;D1 7 ;D2 143 ;D3 1416 ;D4 31787 ;D5 310862 ;D6 7382896"),
		std::string("B6b/8/8/8/2K5/5k2/8/b6B b - - 0 1 ;D1 6 ;D2 106 ;D3 1829 ;D4 31151 ;D5 530585 ;D6 9250746"),
		std::string("8/8/1B6/7b/7k/8/2B1b3/7K b - - 0 1 ;D1 17 ;D2 309 ;D3 5133 ;D4 93603 ;D5 1591064 ;D6 29027891"),
		std::string("k7/B7/1B6/1B6/8/8/8/K6b b - - 0 1 ;D1 7 ;D2 143 ;D3 1416 ;D4 31787 ;D5 310862 ;D6 7382896"),
		std::string("K7/b7/1b6/1b6/8/8/8/k6B b - - 0 1 ;D1 21 ;D2 144 ;D3 3242 ;D4 32955 ;D5 787524 ;D6 7881673"),
		std::string("7k/RR6/8/8/8/8/rr6/7K w - - 0 1 ;D1 19 ;D2 275 ;D3 5300 ;D4 104342 ;D5 2161211 ;D6 44956585"),
		std::string("R6r/8/8/2K5/5k2/8/8/r6R w - - 0 1 ;D1 36 ;D2 1027 ;D3 29215 ;D4 771461 ;D5 20506480 ;D6 525169084"),
		std::string("7k/RR6/8/8/8/8/rr6/7K b - - 0 1 ;D1 19 ;D2 275 ;D3 5300 ;D4 104342 ;D5 2161211 ;D6 44956585"),
		std::string("R6r/8/8/2K5/5k2/8/8/r6R b - - 0 1 ;D1 36 ;D2 1027 ;D3 29227 ;D4 771368 ;D5 20521342 ;D6 524966748"),
		std::string("6kq/8/8/8/8/8/8/7K w - - 0 1 ;D1 2 ;D2 36 ;D3 143 ;D4 3637 ;D5 14893 ;D6 391507"),
		std::string("6KQ/8/8/8/8/8/8/7k b - - 0 1 ;D1 2 ;D2 36 ;D3 143 ;D4 3637 ;D5 14893 ;D6 391507"),
		std::string("K7/8/8/3Q4/4q3/8/8/7k w - - 0 1 ;D1 6 ;D2 35 ;D3 495 ;D4 8349 ;D5 166741 ;D6 3370175"),
		std::string("6qk/8/8/8/8/8/8/7K b - - 0 1 ;D1 22 ;D2 43 ;D3 1015 ;D4 4167 ;D5 105749 ;D6 419369"),
		std::string("6KQ/8/8/8/8/8/8/7k b - - 0 1 ;D1 2 ;D2 36 ;D3 143 ;D4 3637 ;D5 14893 ;D6 391507"),
		std::string("K7/8/8/3Q4/4q3/8/8/7k b - - 0 1 ;D1 6 ;D2 35 ;D3 495 ;D4 8349 ;D5 166741 ;D6 3370175"),
		std::string("8/8/8/8/8/K7/P7/k7 w - - 0 1 ;D1 3 ;D2 7 ;D3 43 ;D4 199 ;D5 1347 ;D6 6249"),
		std::string("8/8/8/8/8/7K/7P/7k w - - 0 1 ;D1 3 ;D2 7 ;D3 43 ;D4 199 ;D5 1347 ;D6 6249"),
		std::string("K7/p7/k7/8/8/8/8/8 w - - 0 1 ;D1 1 ;D2 3 ;D3 12 ;D4 80 ;D5 342 ;D6 2343"),
		std::string("7K/7p/7k/8/8/8/8/8 w - - 0 1 ;D1 1 ;D2 3 ;D3 12 ;D4 80 ;D5 342 ;D6 2343"),
		std::string("8/2k1p3/3pP3/3P2K1/8/8/8/8 w - - 0 1 ;D1 7 ;D2 35 ;D3 210 ;D4 1091 ;D5 7028 ;D6 34834"),
		std::string("8/8/8/8/8/K7/P7/k7 b - - 0 1 ;D1 1 ;D2 3 ;D3 12 ;D4 80 ;D5 342 ;D6 2343"),
		std::string("8/8/8/8/8/7K/7P/7k b - - 0 1 ;D1 1 ;D2 3 ;D3 12 ;D4 80 ;D5 342 ;D6 2343"),
		std::string("K7/p7/k7/8/8/8/8/8 b - - 0 1 ;D1 3 ;D2 7 ;D3 43 ;D4 199 ;D5 1347 ;D6 6249"),
		std::string("7K/7p/7k/8/8/8/8/8 b - - 0 1 ;D1 3 ;D2 7 ;D3 43 ;D4 199 ;D5 1347 ;D6 6249"),
		std::string("8/2k1p3/3pP3/3P2K1/8/8/8/8 b - - 0 1 ;D1 5 ;D2 35 ;D3 182 ;D4 1091 ;D5 5408 ;D6 34822"),
		std::string("8/8/8/8/8/4k3/4P3/4K3 w - - 0 1 ;D1 2 ;D2 8 ;D3 44 ;D4 282 ;D5 1814 ;D6 11848"),
		std::string("4k3/4p3/4K3/8/8/8/8/8 b - - 0 1 ;D1 2 ;D2 8 ;D3 44 ;D4 282 ;D5 1814 ;D6 11848"),
		std::string("8/8/7k/7p/7P/7K/8/8 w - - 0 1 ;D1 3 ;D2 9 ;D3 57 ;D4 360 ;D5 1969 ;D6 10724"),
		std::string("8/8/k7/p7/P7/K7/8/8 w - - 0 1 ;D1 3 ;D2 9 ;D3 57 ;D4 360 ;D5 1969 ;D6 10724"),
		std::string("8/8/3k4/3p4/3P4/3K4/8/8 w - - 0 1 ;D1 5 ;D2 25 ;D3 180 ;D4 1294 ;D5 8296 ;D6 53138"),
		std::string("8/3k4/3p4/8/3P4/3K4/8/8 w - - 0 1 ;D1 8 ;D2 61 ;D3 483 ;D4 3213 ;D5 23599 ;D6 157093"),
		std::string("8/8/3k4/3p4/8/3P4/3K4/8 w - - 0 1 ;D1 8 ;D2 61 ;D3 411 ;D4 3213 ;D5 21637 ;D6 158065"),
		std::string("k7/8/3p4/8/3P4/8/8/7K w - - 0 1 ;D1 4 ;D2 15 ;D3 90 ;D4 534 ;D5 3450 ;D6 20960"),
		std::string("8/8/7k/7p/7P/7K/8/8 b - - 0 1 ;D1 3 ;D2 9 ;D3 57 ;D4 360 ;D5 1969 ;D6 10724"),
		std::string("8/8/k7/p7/P7/K7/8/8 b - - 0 1 ;D1 3 ;D2 9 ;D3 57 ;D4 360 ;D5 1969 ;D6 10724"),
		std::string("8/8/3k4/3p4/3P4/3K4/8/8 b - - 0 1 ;D1 5 ;D2 25 ;D3 180 ;D4 1294 ;D5 8296 ;D6 53138"),
		std::string("8/3k4/3p4/8/3P4/3K4/8/8 b - - 0 1 ;D1 8 ;D2 61 ;D3 411 ;D4 3213 ;D5 21637 ;D6 158065"),
		std::string("8/8/3k4/3p4/8/3P4/3K4/8 b - - 0 1 ;D1 8 ;D2 61 ;D3 483 ;D4 3213 ;D5 23599 ;D6 157093"),
		std::string("k7/8/3p4/8/3P4/8/8/7K b - - 0 1 ;D1 4 ;D2 15 ;D3 89 ;D4 537 ;D5 3309 ;D6 21104"),
		std::string("7k/3p4/8/8/3P4/8/8/K7 w - - 0 1 ;D1 4 ;D2 19 ;D3 117 ;D4 720 ;D5 4661 ;D6 32191"),
		std::string("7k/8/8/3p4/8/8/3P4/K7 w - - 0 1 ;D1 5 ;D2 19 ;D3 116 ;D4 716 ;D5 4786 ;D6 30980"),
		std::string("k7/8/8/7p/6P1/8/8/K7 w - - 0 1 ;D1 5 ;D2 22 ;D3 139 ;D4 877 ;D5 6112 ;D6 41874"),
		std::string("k7/8/7p/8/8/6P1/8/K7 w - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4354 ;D6 29679"),
		std::string("k7/8/8/6p1/7P/8/8/K7 w - - 0 1 ;D1 5 ;D2 22 ;D3 139 ;D4 877 ;D5 6112 ;D6 41874"),
		std::string("k7/8/6p1/8/8/7P/8/K7 w - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4354 ;D6 29679"),
		std::string("k7/8/8/3p4/4p3/8/8/7K w - - 0 1 ;D1 3 ;D2 15 ;D3 84 ;D4 573 ;D5 3013 ;D6 22886"),
		std::string("k7/8/3p4/8/8/4P3/8/7K w - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4271 ;D6 28662"),
		std::string("7k/3p4/8/8/3P4/8/8/K7 b - - 0 1 ;D1 5 ;D2 19 ;D3 117 ;D4 720 ;D5 5014 ;D6 32167"),
		std::string("7k/8/8/3p4/8/8/3P4/K7 b - - 0 1 ;D1 4 ;D2 19 ;D3 117 ;D4 712 ;D5 4658 ;D6 30749"),
		std::string("k7/8/8/7p/6P1/8/8/K7 b - - 0 1 ;D1 5 ;D2 22 ;D3 139 ;D4 877 ;D5 6112 ;D6 41874"),
		std::string("k7/8/7p/8/8/6P1/8/K7 b - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4354 ;D6 29679"),
		std::string("k7/8/8/6p1/7P/8/8/K7 b - - 0 1 ;D1 5 ;D2 22 ;D3 139 ;D4 877 ;D5 6112 ;D6 41874"),
		std::string("k7/8/6p1/8/8/7P/8/K7 b - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4354 ;D6 29679"),
		std::string("k7/8/8/3p4/4p3/8/8/7K b - - 0 1 ;D1 5 ;D2 15 ;D3 102 ;D4 569 ;D5 4337 ;D6 22579"),
		std::string("k7/8/3p4/8/8/4P3/8/7K b - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4271 ;D6 28662"),
		std::string("7k/8/8/p7/1P6/8/8/7K w - - 0 1 ;D1 5 ;D2 22 ;D3 139 ;D4 877 ;D5 6112 ;D6 41874"),
		std::string("7k/8/p7/8/8/1P6/8/7K w - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4354 ;D6 29679"),
		std::string("7k/8/8/1p6/P7/8/8/7K w - - 0 1 ;D1 5 ;D2 22 ;D3 139 ;D4 877 ;D5 6112 ;D6 41874"),
		std::string("7k/8/1p6/8/8/P7/8/7K w - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4354 ;D6 29679"),
		std::string("k7/7p/8/8/8/8/6P1/K7 w - - 0 1 ;D1 5 ;D2 25 ;D3 161 ;D4 1035 ;D5 7574 ;D6 55338"),
		std::string("k7/6p1/8/8/8/8/7P/K7 w - - 0 1 ;D1 5 ;D2 25 ;D3 161 ;D4 1035 ;D5 7574 ;D6 55338"),
		std::string("3k4/3pp3/8/8/8/8/3PP3/3K4 w - - 0 1 ;D1 7 ;D2 49 ;D3 378 ;D4 2902 ;D5 24122 ;D6 199002"),
		std::string("7k/8/8/p7/1P6/8/8/7K b - - 0 1 ;D1 5 ;D2 22 ;D3 139 ;D4 877 ;D5 6112 ;D6 41874"),
		std::string("7k/8/p7/8/8/1P6/8/7K b - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4354 ;D6 29679"),
		std::string("7k/8/8/1p6/P7/8/8/7K b - - 0 1 ;D1 5 ;D2 22 ;D3 139 ;D4 877 ;D5 6112 ;D6 41874"),
		std::string("7k/8/1p6/8/8/P7/8/7K b - - 0 1 ;D1 4 ;D2 16 ;D3 101 ;D4 637 ;D5 4354 ;D6 29679"),
		std::string("k7/7p/8/8/8/8/6P1/K7 b - - 0 1 ;D1 5 ;D2 25 ;D3 161 ;D4 1035 ;D5 7574 ;D6 55338"),
		std::string("k7/6p1/8/8/8/8/7P/K7 b - - 0 1 ;D1 5 ;D2 25 ;D3 161 ;D4 1035 ;D5 7574 ;D6 55338"),
		std::string("3k4/3pp3/8/8/8/8/3PP3/3K4 b - - 0 1 ;D1 7 ;D2 49 ;D3 378 ;D4 2902 ;D5 24122 ;D6 199002"),
		std::string("8/Pk6/8/8/8/8/6Kp/8 w - - 0 1 ;D1 11 ;D2 97 ;D3 887 ;D4 8048 ;D5 90606 ;D6 1030499"),
		std::string("n1n5/1Pk5/8/8/8/8/5Kp1/5N1N w - - 0 1 ;D1 24 ;D2 421 ;D3 7421 ;D4 124608 ;D5 2193768 ;D6 37665329"),
		std::string("8/PPPk4/8/8/8/8/4Kppp/8 w - - 0 1 ;D1 18 ;D2 270 ;D3 4699 ;D4 79355 ;D5 1533145 ;D6 28859283"),
		std::string("n1n5/PPPk4/8/8/8/8/4Kppp/5N1N w - - 0 1 ;D1 24 ;D2 496 ;D3 9483 ;D4 182838 ;D5 3605103 ;D6 71179139"),
		std::string("8/Pk6/8/8/8/8/6Kp/8 b - - 0 1 ;D1 11 ;D2 97 ;D3 887 ;D4 8048 ;D5 90606 ;D6 1030499"),
		std::string("n1n5/1Pk5/8/8/8/8/5Kp1/5N1N b - - 0 1 ;D1 24 ;D2 421 ;D3 7421 ;D4 124608 ;D5 2193768 ;D6 37665329"),
		std::string("8/PPPk4/8/8/8/8/4Kppp/8 b - - 0 1 ;D1 18 ;D2 270 ;D3 4699 ;D4 79355 ;D5 1533145 ;D6 28859283"),
		std::string("n1n5/PPPk4/8/8/8/8/4Kppp/5N1N b - - 0 1 ;D1 24 ;D2 496 ;D3 9483 ;D4 182838 ;D5 3605103 ;D6 71179139"),
		std::string("8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1 ;D1 14 ;D2 191 ;D3 2812 ;D4 43238 ;D5 674624 ;D6 11030083"),
		std::string("rnbqkb1r/ppppp1pp/7n/4Pp2/8/8/PPPP1PPP/RNBQKBNR w KQkq f6 0 3 ;D1 31 ;D2 570 ;D3 17546 ;D4 351806 ;D5 11139762;D6 244063299")
	};

	static std::vector<std::string> GetElements(std::string strToSplit, char delimeter)
	{
		std::stringstream ss(strToSplit);
		std::string item;
		std::vector<std::string> splittedStrings;
		while (std::getline(ss, item, delimeter))
		{
			splittedStrings.push_back(item);
		}
		return splittedStrings;
	}

}
Worlds-fastest-Bitboard-Chess-Movegenerator
Daniel Inführ - Software Developer
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R. Tomasi
Posts: 307
Joined: Wed Sep 01, 2021 4:08 pm
Location: Germany
Full name: Roland Tomasi

Re: perft test

Post by R. Tomasi »

dangi12012 wrote: ↑Fri Sep 24, 2021 12:18 pm Dont try the default fen - there are many - many - many bugs that are hidden until later positions.
Absolutely.

I have a special test-movegen command in my engine that will do perft at different depth for many positions that are stored (with the correct result) in a table. It will automatically run all these perfts and compare them with the expected results. Whenever I touch anything related to move-generation I run that command to ensure that I did not introduce any bug.
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MartinBryant
Posts: 87
Joined: Thu Nov 21, 2013 12:37 am
Location: Manchester, UK
Full name: Martin Bryant

Re: perft test

Post by MartinBryant »

The 6th ply from the root position is where black gets its first chance to capture en-passant (I think?)
Have you double-checked your en-passant code for black?

To verify it is correct try doing a perft(2) search on a much simpler position like...
3k4/8/8/8/4p3/8/3P4/3K4 w - - 0 1
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giggetto71
Posts: 3
Joined: Tue Aug 31, 2021 8:33 am
Full name: Pierluigi Meloni

Re: perft test

Post by giggetto71 »

wow! so many responses full of great advices! this is my first post and I really did not expect such level of support! Thanks to some of small FENs found in the responses I identified a couple of hidden bugs related to the 0-0..I will keep searching!
THANKS SOOO MUCH to all!
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dangi12012
Posts: 1062
Joined: Tue Apr 28, 2020 10:03 pm
Full name: Daniel Infuehr

Re: perft test

Post by dangi12012 »

Try that position: https://lichess.org/analysis/8/2p5/3p4/ ... b_-_e3_0_1
Checked by Enpassant pawn - Accept Enpassant to stop the check
Worlds-fastest-Bitboard-Chess-Movegenerator
Daniel Inführ - Software Developer
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JVMerlino
Posts: 1404
Joined: Wed Mar 08, 2006 10:15 pm
Location: San Francisco, California

Re: perft test

Post by JVMerlino »

I've posted these before, but I'll do it again so you don't have to look around for them.

r3k2r/8/8/8/3pPp2/8/8/R3K1RR b KQkq e3 0 1 // perft(6) = 485,647,607
r3k2r/Pppp1ppp/1b3nbN/nP6/BBP1P3/q4N2/Pp1P2PP/R2Q1RK1 w kq - 0 1 // perft(6) = 706,045,033
8/7p/p5pb/4k3/P1pPn3/8/P5PP/1rB2RK1 b - d3 0 28 // perft(6) = 38,633,283
8/3K4/2p5/p2b2r1/5k2/8/8/1q6 b - - 1 67 // perft(7) = 493,407,574
rnbqkb1r/ppppp1pp/7n/4Pp2/8/8/PPPP1PPP/RNBQKBNR w KQkq f6 0 3 // perft(6) = 244,063,299
r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - // perft(5) = 193,690,690
8/p7/8/1P6/K1k3p1/6P1/7P/8 w - - // perft(8) = 8,103,790
n1n5/PPPk4/8/8/8/8/4Kppp/5N1N b - - // perft(6) = 71,179,139
r3k2r/p6p/8/B7/1pp1p3/3b4/P6P/R3K2R w KQkq - // perft(6) = 77,054,993
8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - // perft(7) = 178,633,661
8/5p2/8/2k3P1/p3K3/8/1P6/8 b - - // perft(8) = 64,451,405
r3k2r/pb3p2/5npp/n2p4/1p1PPB2/6P1/P2N1PBP/R3K2R w KQkq - // perft(5) = 29,179,893
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pedrojdm2021
Posts: 157
Joined: Fri Apr 30, 2021 7:19 am
Full name: Pedro Duran

Re: perft test

Post by pedrojdm2021 »

You can download stockfish and run:

Code: Select all

position fen your_perft_fen
go perft perft_depth
it will print each move with the number of child moves on each item.
you have to program your engine that outputs the move string with the number of child moves too just as stockfish does.

then you have to compare it with stockfish and find differences. OR program a functon that reads some sort of .txt file that you create with stockfish information and compare it and prints differences for you (this will save you a LOT of time, i do that in my engine and is a hugue time saver for debugging. )

When you find a difference then repeat the process with the move:

imagine that starting position on the move a2a3 is printing different value compared with stockfish in depth of 3:

now i can execute

Code: Select all

position fen fen_starting_position moves a2a3
go perft 2
and it will print me the data for the sub-tree of that a2a3, and then you have to repeat the process like you did in the root node, continue until you reach a depth of 1.

and you will end up in the position that is generating the issue.

if you reach depth of 1, and you find that the position is printing the correct results, then it's something wrong with your move make/unmake function.
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