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Subject: Re: Gandalf HASH notice for all!!

Author: Dann Corbit

Date: 16:15:02 01/09/01

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On January 09, 2001 at 08:12:21, Steffen Jakob wrote:

>[...]
>
>>>Setting a flag takes some time especially if its part of a bitset in a data
>>>type. I wrote a little example where setting the flags of 160 MB takes 1.75
>>>seconds on my machine. Clearing the whole table with memset() takes 1.02
>>>seconds. I dont know, but if Steend does something additionally it might take 5
>>>seconds (or if the RAM is slower).
>>
>>Okay, your numbers are not unreasonable. You are still far below Jouni's 5 - 10
>>seconds. I got ~ 0.5 secs to clear 64 MB with memset on my machine.
>>I think that you must really do a lot per entry in order to make it take 5-10
>>seconds. Wouldn't you agree to this, Steffen ?
>
>Yes, you are right. Maybe Steen can give us some information why it takes so
>long.
>
>Greetings,
>Steffen.
>
>P.S.: I once had a discussion with Chrilly about reducing the hash size when you
>are low on time and he agreed that this was a good idea (but I dont think that
>he added this to Nimzo).

When doing EPD analysis with Crafty, if the time control is only a few seconds I
get better results (deeper plies, higher NPS) by using a smaller hashsize than
for deep analysis.  I like 32 megs for 5 seconds, and 320 megs for one hour
(machine has 512 megs).



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