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Subject: Re: new questions (scott gasch!)

Author: Daniel Shawul

Date: 00:42:23 11/22/04

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On November 21, 2004 at 23:36:11, Robert Hyatt wrote:

>On November 21, 2004 at 19:14:35, Dan Honeycutt wrote:
>
>>On November 21, 2004 at 12:18:58, Robert Hyatt wrote:
>>
>>>
>>>If you plan on hacking and testing, repeated for a _long_ time, that is the way
>>>to go.  The first parallel version of Crafty (version 15.0) was designed, then
>>>written, after the complete approach had been considered, designed, and
>>>carefully evaluated...  only _then_ did the first line of code get written.
>>>
>>
>>*   15.0    this is the first version to support a parallel search using      *
>>*           multiple processors on a shared-memory machinel.  this version    *
>>*           uses the "PVS" algorithm (Principal Variation Search) that is an  *
>>*           early form of "Young Brothers Wait".  this is not the final       *
>>*           search algorithm that will be used, but it is relatively easy to  *
>>*           implement, so that the massive data structure changes can be de-  *
>>*           bugged before getting too fancy.  the major performance problem   *
>>
>>Sounds like what Daniel is doing, something relatively easy to implement so he
>>can test and debug before getting too fancy.
>>
>>Dan H.
>
>Didn't to me.  The version above had the current parallel search implemented in
>total.  All parts were not enabled initially to attempt to avoid introducing too
>many bugs at one time...  but the program as it exists today was designed
>completely in 15.0, from the parallel search perspective.  Only change after
>that point was adding the ability to split the tree at the root, something that
>is a bit more problematic than splitting at ply 2 or deeper.
>
>My reading Daniel's post sounds like he is just writing code left and right
>without having a clear idea of what the ultimate parallel search algorithm will
>look like.  That's a recipe for lots of debugging and rewriting.

  Why don't we end the discussion like this. I think i am doing the right thing
, you think i don't have a clue. The biggest design change may occur if i decide
to use YBW [which i don't think will be able to even try soon],until then
i will enjoy myself with the simple things which i can do.Like pvs splitting
which will aquaint me more with parallel searching stuff. And if i ever decide
to change to DTS or YBW and i have to make a big design change, i will not be
asking lots of programming questions like i am doing right now.Until then,I
would like to keep it simple and have something to experiment with. I don't
expect speed up numbers just something which works which i think i managed to
do.

daniel






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