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Subject: Re: Forced moves

Author: Ed Schröder

Date: 10:44:40 08/03/99

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On August 03, 1999 at 13:14:37, Eugene Nalimov wrote:

>If I understand Ed properly, he wrote "Customers do not like when the program
>for several minutes thinks on the obvious move. And they don't like it so much,
>that I have to solve that problem somwhow, even if solution is not 100% correct
>and sometimes causes bad play".
>
>Eugene

That was indeed the starting point some 10 years ago when I made a first
implementation of the easy-move algorithm. In the beginning the error
rate was quite high (6502 5Mhz) but people were satisfied.

These days the easy-move algorithm is a lot better plus the fast hardware
of today guarantees no single error anymore. Well... maybe one a year?

Rebel depending on the position divides its time by 2,4 or 8.

Ed Schroder



>On August 03, 1999 at 09:14:30, Robert Hyatt wrote:
>
>>On August 03, 1999 at 05:25:52, Ed Schröder wrote:
>>
>>>>Posted by leonid on August 02, 1999 at 21:23:37:
>>>>
>>>>>IMHO low-brain fast-searches like DB vs Kasparov have proved it is better to
>>>>>forget about trouble makers and exceptions and just go for the brute force
>>>>>approach. Fast and dumb rules. Forget about exceptions they are waste of
>>>>>time.
>>>>>You spend all clock cycles and programmer time on worrying about
>>>>>exceptions and then you are full of bugs.
>>>>>
>>>>>Ciao
>>>>>
>>>>>Mark
>>>>>
>>>>>
>>>>>>
>>>>>>And because of today's fast computers the exceptions fade away as for
>>>>>>example the Cray Blitz position is seen by Rebel in 0.5 second.
>>>>>>
>>>>>>Ed Schroder
>>>>
>>>>I really agree with what was said obove. Now on very quick computers Rebel
>>>>10 can see by "brute force" 6 plys ahead in just one or two seconds. Some
>>>>less superficial revision of the moves but with "fixed horizon" can lead up
>>>>to 10 or even 12 plys deep. This way of searching the move is best
>>>>that some other method that care too much about exceptions. Exceptions
>>>>that take that much space to care about and can produce anyway very
>>>>suspicious result.
>>>>
>>>>Leonid.
>>>
>>>I do not agree with was has been said above except what has been said
>>>by myself of course :-)
>>>
>>>If you have a commercial program and playing a 40/2:00 game for instance
>>>you can not afford to think 6 minutes (or worse) on a simple recapture as
>>>people are going to laugh on the stupidness of the silicon.
>>>
>>>So you are forced to come up with some intelligent software that handles
>>>forced moves. This means you are going to have to deal with all the
>>>exceptions. No choice.
>>>
>>>Ed Schroder
>>
>>
>>That is debatable...  I think your reasoning is a dead match for the reasons
>>that Slate/Atkin used for their famous "that was easy" idea in chess 4.x...
>>they didn't like sitting for N minutes on an obvious recapture.  Many of us
>>didn't want to look silly like that.  And often (or probably all of the time
>>in fact) the fix was actually worse than the "problem".  But we didn't realize
>>this until we got burned once...
>>
>>then the question is, which is worse...  to take forever on an obvious more or
>>get burned by playing an 'obvious' move that really isn't?



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