Author: Angrim
Date: 16:04:00 10/16/03
Go up one level in this thread
On October 16, 2003 at 03:16:58, Axel Schumacher wrote: >Hi, >I stumbled across the new engine Gothic Vortex, which seems to be a 80 bit >engine! What is your opinion to this approach? This looks like a fairly normal bitboard engine once you overlook the hype. Obviously a bitboard engine for the gothic chess variant will have to be useing 80 bits per board. >http://www.gothicchess.org/gothic_vortex.html > >Excerpt from the page: <snip> >It is possible to use an Array Move Generator. Most programmers who attempt to >write something as complex as a chess program first build an Array Move >Generator. On the plus side, an Array Move Generator is easier to program and >debug. It also "makes sense" to think in terms of an Array Move Generator, since >the computer instructions used to encode the program closely resemble the >process a human player might use to do the same thing. On the minus side, an >Array Move Generator is many times slower than a Bitboard Move Generator. A >recent experiment showed that the Bitboard Move Generator in the Gothic Vortex >program is about 30 times as fast as the Array Move Generator found in the >Zillions-Of-Games engine. As noted elsewhere, this is a straw man. ZoG may be useing an array move generator, but that is irrelevant to its speed, which is based on the fact that it has a general-purpose movegen which has to interpret the rules to the game that it is currently playing rather than a custom-built one that is designed for a specific game. >All of this was mentioned because Gothic Chess, with an 80 square board, is even >more difficult to implement as a Bitboard Move Generator. There are no 80-bit >operating systems, and the types of 80-bit instructions that are needed for >maximum speed of execution are just not available. Writing code to handle the >data as three discrete packets of 32-, 32-, and 16-bit chunks is so tedious that >it almost defies a rational explanation. > >What is needed is an 80-bit emulation core, and this is very difficult to >design. What is needed is to use C++ and create a bitboard80 class which implements the bit level operators. This is really simple. >Just designing such a core was a huge project unto itself. Once the core was >completed, the rest of the game shell had to be designed around it. Using >something known as 45-degree rotated bitboards for an 80 square board and >intelligent 80-bit register shifts, the Gothic Chess engine was hand crafted. >The result was the equivalent of a Nitrous Oxide powered dragster. > >Gothic Vortex is capable of performing very deep searches in only a matter of >seconds! The web page makes repeated references to matches against Zog, for those to be at all interesting says a lot about how good ZoG is and little about how strong the custom engine is. Hmm, anyone want to set up a ZoG version that can play suicide chess, and run it on FICS so that I can pick on it? I'll offer 120:1 time odds(0.1 seconds a move vs 12 seconds a move) :) Angrim
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