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Subject: Re: How many nodes do you need to search 15 plies?

Author: blass uri

Date: 20:36:51 07/21/00

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On July 21, 2000 at 23:27:47, Robert Hyatt wrote:

<snipped>
>Here is my numbers, on a quad xeon/550mhz machine.
>
>9 plies took 2M nodes
>10 plies took 5M nodes (this is 5M total from plies 1-10)
>11 plies took 9M nodes
>12 plies took 100M nodes
>13 plies took 500M nodes
>14 plies took 700M nodes
>15 plies took 1300M nodes
>
>If I could average 200M nodes per second, I could do that search in probably
>under 5 seconds, given enough memory.  If I could peak at 1B, I could do that
>search between 1 and 5 seconds somewhere, depending on how the peak went...
>
>Note that his 30% efficiency figure is an average as is my 3.2X faster on a
>quad.  I have many positions where I run 4x faster.  I have a couple where
>I run 1/10th as fast as one cpu...
>
>For me, these numbers should be reduced by at least 25%, which is my search
>overhead (extra nodes searched that a sequential search would not examine).
>Hsu's 200M figure already had his overhead factored out...
>
>I am not sure what this proves, when you factor in parallel search.  Odd
>things happen.  Some searches go way fast.  Others go way slow.  Trying to
>compare searches by comparing depths is not so useful.  In some positions
>I might extend way too much.   In other positions they might do the same.
>In other positions we might extend pretty equally. How to know and compare?
>
>I could probably search this tree in less than 1/2 the nodes if I had a decent
>sized hash table.  This grossly overruns anything I can use on this machine
>tonight...

Did you use recursive null move pruning in this search?(I think you should not
use null move pruning in order to do the right comparison)

Uri




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