Author: Robert Hyatt
Date: 14:21:40 07/30/03
Go up one level in this thread
On July 30, 2003 at 16:31:50, Angrim wrote: >On July 29, 2003 at 23:56:03, Robert Hyatt wrote: > >>You finally reached the ultimate conclusion. :) >> >>But to re-iterate another point, perft is a correctness benchmark _only_, as it >>is defined. It is _not_ a performance benchmark. If it were, most of us would >>write it differently, certainly using hashing to avoid traversing duplicate >>parts of the tree searched due to transpositions. > >That would be monumentally stupid, unless the numbers were being used by >a marketing department to sell the engine or something. If the goal is >for the person who is coding the perft() to find out how his movegen, makemove, >and unmakemove speed compares to others to get an idea of how much he >could speed it up, or to compare the speed of two different versions of >his own movegen, then there is no rational reason to cheat, since this >only hurts himself. That wasn't why it was first done. It was done to catch generator/make/unmake _errors_ which then cause the count to go wrong. IE it helped many of us find bugs in en passant captures, castling errors, pawn promotion errors, illegal move errors, etc. >This is like someone designing a racecar trying to benchmark how fast >their car is by putting it up on blocks and taking the wheels off, and >timing how fast the axles rotate. > I think that timing perft can be a useful benchmark, as long as you >code perft as defined and visit each leaf node. If you use hash tables >and avoid visiting the leaf nodes, then you have written something that >outputs the same number as perft does, but it isn't the same function. > >Angrim Comparing times is not particularly useful, unless you both do the same kinds of things in make/unmake move. IE for someone that incrementally updates some global pawn structure values, their make/unmake will be slower, their perft result will be slower, but their program might actually be faster overall.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.