Author: Robert Hyatt
Date: 16:41:30 11/22/01
Go up one level in this thread
On November 22, 2001 at 15:52:22, Uri Blass wrote: >The times of my program in calculating perft(number of legal games of fixed >number of plies) are not bad. > >I get on p800 33 seconds for finding perft 6=119060324 in the initial position >and also 33 seconds for finding perft 5=193690690 in another known position > >this is not a mistake and my program needs similiar time because it generates >only legal moves so it needs less nodes to calculate perft 5. > > >[D]r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1 > > >I am interested to know what is the speed of the best free or commercial program >in calculating perft. > >Yace is the fastest free program that I know. >I do not know about a commercial programs with this function. > > >My move generator is not 100% correct because it has some probelms with the en >passant rule that I did not care to fix but it finds the right numbers and it is >clear that fixing the errors is not going to change significantly the speed of >the program. > > >yace is slightly faster than my program in caculating perft 6 in the initial >position(32 seconds) but has no chance in the second position and I plan to >improve the algorithm(there wer important things that I did not do because of >more important things). > >The main improvement that I worked about in the last days was improvement in >generating moves(my previous version generated only piece go to square when I >started from the target square and now I start from the piece except checks). > >second improvement that I found was a mistake of generating move twice when I >did not need to do it. > >I calculate perft 4 in the following ways: >1)generate all legal moves >2)make a3 >3)generate all legal moves >4)make a6 >5)generate all the legal moves >6)make a4 >7)generate all the legal moves and add their number into perft The original idea behind perft was to measure move generation _and_ make/unmake speed. IE if you do perft 4, a program would generate and make every move up to 4 plies deep. You are cutting off the last ply of make/unmake, which is ok, but it isn't comparable to the original intent of this. Otherwise everybody will go faster by dumping the last layer of make/unmake which is expensive... >8)undo a4 >9)generate all the legal moves >10)make b3 >11)generate all the legal moves and add their number to perft >12)undo b3 >13)generate all the legalmoves >14)make b4 > >I understood that I can save time by not doing 9,13,... because it was exactly >the same job that I did in 5 and it saved me almost half of the job of >generating moves(it was not close to 50% improvement because my program also >make moves and not only generates them but it was a big improvement). > >Uri
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