Author: KarinsDad
Date: 11:49:37 05/20/99
Go up one level in this thread
On May 20, 1999 at 13:31:53, Dann Corbit wrote: >On May 19, 1999 at 20:55:40, Eugene Nalimov wrote: > >>I'm participating in that thread because I'm curious: how much we can "squeeze" >>the average position. Unfortunately, I don't see who will implement suggested >>algorithms and where it'll be used. >> >>To speak more generally, I can see 3 different goals for such the algorithm that >>results in 3 different representation requirements: >>(1) To store the entire game in the least possible # of bits. Here, as it was >>pointed earlier, you'd better store starting position (if necessary) and >>sequence of moves. >>(2) To store the random position in the *fixed* number of bits, so that the >>resulting file (database?) can be directly indexed. That means you have to >>optimize the worst case. And here majority of the clever tricks (e.g. using less >>bits for pawns or pieces on the 1st/8th ranks) will not work. IMHO, that >>representation must be able to cover even the pathological cases that cannot >>happen in the real games. >>(3) To store the *average* position in the minimum amount of bits. That >>representation can work if you plan to use only sequental search through those >>positions. And here is the place of KarinsDad's schema - *average* position will >>be stored significally better than by using the algorithm from the case (2). >I think I should make clear why I brought it up in the first place. For *my* >purposes, I do not necessarily need the very smallest conceivable. I just want >something very small and very fast and easy to understand. It will be used to >take a few hundred thousand EPD records and create an in-memory table for >lookups. Hence, it has to work in the general case. I looked over some common >schemes and just wanted to make sure that I was not overlooking something >important that could save a lot of space. To store games, you could use a >scheme like pigbase which only needs one byte per position. But I don't want >that. I need to be able to access a random position that may not even be >connected to other positions. This being the case Dann, why not just use the internal structure from EPD? It's about as fast as you can probably get and takes up 24 bytes per position. KarinsDad :)
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