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Subject: Re: The need to unmake move

Author: Vincent Diepeveen

Date: 09:30:37 09/03/03

Go up one level in this thread


On September 03, 2003 at 10:57:17, Sune Fischer wrote:

>On September 03, 2003 at 10:51:56, Vincent Diepeveen wrote:
>
>>On September 03, 2003 at 10:44:11, Sune Fischer wrote:
>>
>>>On September 03, 2003 at 10:35:11, Gian-Carlo Pascutto wrote:
>>>
>>>>On September 03, 2003 at 10:26:19, Sune Fischer wrote:
>>>>
>>>>>>What is your point?
>>>>>
>>>>>Heh :)
>>>>>
>>>>>You said (remote) checking for fail_high conditions at every node was required,
>>>>>and I disagree.
>>>>
>>>>I never say 'at every node'.
>>>
>>>You said constantly, then I don't know what you mean by that.
>>>
>>>>Each time you get a subtree score, you must send out the score update to
>>>>all processors, or store it locally and rely on remote processors to check
>>>>it in your memory.
>>>>
>>>>Either way, you need remote accesses.
>>>>
>>>>Got it now?
>>>
>>>This is an entirely different matter, you don't get subtree scores "constantly".
>>>And I still say you only have to access when there is something to communicate.
>>>
>>>If you just quietly exit the subtree on a fail low, I see no need for
>>>communication.
>>
>>And how big is your search going to be. 10 ply minimax?
>>
>>Or do you prefer 10 ply alfabeta + nullmove.
>>
>>How many times is your processor going to check whether he is doing work for
>>nothing?
>>
>>Each node?
>>Each 10 million nodes?
>>
>>The advantage of each node is that it won't idle too much.
>>The advantage of each 10 million nodes is that you don't eat up bandwidth, but
>>that your search will be as bad as a single cpu.
>>
>>So how are you going to do it?
>
>Ah yes, agreed.
>There is a treade off to be made here, some experiments would have to help me
>decide on that.
>
>But since you don't want to spawn new search threads constantly, you don't
>terminate search threads constantly either. As a matter of fact the numbers are
>identical.

I hope you realize that when Huber said his thing would work like the
sun on that machine in july 2002,  that i was pretty amazed to hear he
spawns each move new processes.

Thanks to some other 300 processors being busy with something eating 200GB ram
(each processor has 1 GB ram) and the i/o being broken (they were upgrading the
machine), just that spawning of 59 diep processes took 15 minutes.

A few months ago when i spawned 129 diep processes (so 130 processes in total)
with just 10GB ram, that took 1.5 hours.

They are currently creating a database of 10 TB with extreme weather predictions
for the coming centuries, so you'll see the results soon at the discovery
channel i guess. Of course they already run for months continuesly at 258
processors (out of 1024).

Let's pray they have finished before november ;)

Thanks,
Vincent

>-S.
>
>>
>>>-S.
>>>>--
>>>>GCP



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