Author: Vincent Diepeveen
Date: 08:25:24 07/04/03
Go up one level in this thread
On July 04, 2003 at 11:18:58, Vincent Diepeveen wrote: >On July 03, 2003 at 13:57:02, Dann Corbit wrote: > >>On July 03, 2003 at 12:28:05, Ralph Stoesser wrote: >> >>>Dear chess programmers, >>> >>>What are your personal experiences with the MTD(f) search introduced by Aske >>>Plaat some years ago? >> >>It does not work for me as well as it does for some others. >> >>I think success will depend very much on your particular engine. >> >>Andrew Williams has a successful implementation. > >Claims to have a successful implementation is more near the truth. > >Hopefully getting a position from hashtable doesn't eat 4 >microseconds with him. For those who do not understand what i mean, let's be clear for the non experts. Aske Plaat claimed a successful implementation of MTD in Cilkchess. However i do not see how it is possible to implement MTD in a supercomputer program. Without hashtables you in advance cannot use MTD. Too expensive researches you need. Average latency at supercomputers is like 4 microseconds - 30 microseconds. In short if you plan to get more than 15000 nodes a second at a cpu, forget it at a supercomputer with MTD. 15000 nps means already hashtable eats 50% of your system time with MTD and in reality it will eat more as you need more than 2 references a node with MTD. 1 read and 1 write. Write is way more expensive than load. This is why cilkchess searched with CILK around 5k nps a cpu and at his laptop without cilk it searched 200k nps. The supercomputer chip was higher clocked than his laptop. Also the supercomputer chip was 64 bits and cilkchess as we all know is a bitboards thing. How can you claim MTD to be succesful then? Best regards, Vincent
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