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Subject: Re: Q&A with Feng-Hsiung Hsu

Author: Uri Blass

Date: 17:50:55 10/17/02

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On October 17, 2002 at 18:21:06, Robert Hyatt wrote:

>On October 17, 2002 at 11:34:35, Uri Blass wrote:
>
>>On October 17, 2002 at 10:41:20, Robert Hyatt wrote:
>>
>>>On October 17, 2002 at 06:13:26, Johan Melin wrote:
>>>
>>>>On October 16, 2002 at 23:35:10, Robert Hyatt wrote:
>>>>
>>>>>On October 15, 2002 at 14:01:35, Johan Melin wrote:
>>>>>
>>>>>>On October 14, 2002 at 07:34:16, Bas Hamstra wrote:
>>>>>>
>>>>>>>Bob, did you read the Hsu transcript posted here? It is pretty clear to me that
>>>>>>>Hsu himself says 12 ply fullwidth *total*. Case closed. Please read the complete
>>>>>>>transcript.
>>>>>>>
>>>>>>>Best regards,
>>>>>>>Bas.
>>>>>>
>>>>>>I agree. The transcript with Hsu is clear. But it would be out of character for
>>>>>>CCC if everybody just agreed with each other, there still has to be a fight ...
>>>>>>;)
>>>>>>
>>>>>>/Johan Melin
>>>>>
>>>>>
>>>>>Here is the relevant part of the transcript:
>>>>>
>>>>
>>>>There are other relevant parts? How about:
>>>>
>>>>----------------------------------
>>>>EeEk(* DM) kibitzes: kib question from ardee: Does "12(6)" mean 12
>>>>total ply or 12+6=18 total ply?  This has the been source of huge
>>>>arguments for years!
>>>>CrazyBird(DM) kibitzes: 12 total in terms of brute force. 6 is just
>>>>the max partition in hardware.
>>>>----------------------------------
>>>>
>>>>He sais 12 _total_. He also refers to 6 as "just", implying that it is less
>>>>important than the 12.
>>>
>>>
>>>No he clearly did _not_ say "12 total".  He said "12 plies of brute force".  He
>>>also
>>>said elsewhere that the _hardware_ does forward pruning.  So "12 plies of brute
>>>force"
>>>implies that is non-hardware...
>>
>>It is not clear from it.
>>
>>suppose the hardware never pruned in the first 3 plies in the hardware when the
>>hardware get depth 6.
>
>I don't disagree, although I know how the hardware was implemented, and it isn't
>nearly
>so clean to try to be asymmetric based on search depth.  This is basically a
>finite state machine
>and it makes far more sense for everything to be done the same way, from ply 1
>to ply N,
>inside the hardware...
>
>
>>Suppose also that the software sent the hardware only lines of at least 9 moves.
>>You can have 12 plies of brute force when 6 is the maximal depth in the
>>hardware.
>
>Sure.  That is why the question needs to be posed properly rather than the vague
>questions
>that were asked the last time...
>
>
>>>
>>>
>>>
>>>>
>>>>If somebody tells you that "the storage capacity of this harddrive is 20 GB, 5
>>>>GB is just the linux partition", then what is the storage capacity? 25 GB?
>>>
>>>No.  But nobody has said that.  they have said "20 gigabytes of space".
>>>The hardware has 5 gigabytes of buffer."  Does the thing have 20 gigs or
>>>25 gigs _now_???  From a speed perspective, it matters how that is done.
>>>
>>>
>>>>
>>>>----------------------------------
>>>>EeEk(* DM) kibitzes: question from parabola444:  You mentioned Deep
>>>>Blue searched about 12 plies brute force + extensions, which is
>>>>similar to what pc programs these days get on a fast pc - since Deep
>>>>Blue hardware was much faster, how come it didn't search significantly
>>>>deeper ?
>>>>CrazyBird(DM) kibitzes: to all the book readers, if you do like the
>>>>book, please tell your friends would might be interested. thanks.
>>>>CrazyBird(DM) kibitzes: replace would with who:).
>>>>CrazyBird(DM) kibitzes: we were using fairly extensive search
>>>>extensions, and the decision not to use null move pruning was an
>>>>deliberate one.
>>>>----------------------------------
>>>>
>>>>The interesting part here is not just what he says, but what he doesn't say. If
>>>>they search 18 plies nominal, he would have said so. Why would he hold back such
>>>>a statement? He indirectly agrees to searching only 12 plies.
>>>
>>>Again, Hsu tries to answer what he is asked, as briefly as possible.  The
>>>hardware does
>>>forward pruning.  They have _always_ given the "software depth" when they
>>>discuss
>>>this kind of number.  Whether he still is is up for debate, but I doubt he would
>>>suddenly
>>>change his terminology after using it for 15 years...
>>>
>>>
>>>
>>>
>>>>
>>>>
>>>>>-----------------------------------------------------------------------------------------------------------------------
>>>>>CrazyBird(DM) kibitzes: 12(6) means 12 plies of brute force (not
>>>>>counting the search extensions & quiescence).
>>>>>CrazyBird(DM) kibitzes: 6 means the maximum hardware search depth
>>>>>allowed.
>>>>>CrazyBird(DM) kibitzes: this means that the PV could be up to 6 plies
>>>>>deeper before quiescence.
>>>>>-----------------------------------------------------------------------------------------------------------------------
>>>>
>>>>Note that in the first line he states "not counting ..." but does not mention
>>>>any extra plies from hardware. Wouldn't 6 plies be more significant than
>>>>quiescence? So why doesn't he mention that it isn't included in the 12 plies?
>>>>
>>>
>>>What about the last sentence.  It seems to say exactly what you say is missing.
>>>
>>>"up to 6 plies deeper".
>>
>>up to 6 plies deeper relative to the logfile.
>>I do not know if they did extensions in the hardware but even if I assume that
>>they did ply can include also extensions.
>>
>>When people says that the program search 6 plies it includes extensions so it is
>>possible that when 6 plies are missing it includes extensions.
>
>But "up to 6" then means "no more than 6 plies of extensions."  I _know_ that
>they
>allowed two plies of extensions for every 2 plies of search, which means that a
>2
>ply search could go to 40+ plies if needed...
>
>The "up to 6" doesn't fit there at all...


My guess is that Hsu meant that the pv could be 6 plies deeper before quiescence
and extensions but forgot to say the word extensions
>
>
>>
>>
>>>
>>>
>>>
>>>
>>>>>
>>>>>OK, some questions:
>>>>>
>>>>>1.  If 12(6) means 12 plies total, with 6 done in hardware, how do you reconcile
>>>>>that
>>>>>_last_ sentence above (the PV could be up to 6 plies _deeper_ before
>>>>>quiescence).
>>>>>Deeper than what?  Only possible answer is deeper than 12 plies.
>>>>
>>>>He is talking about the PV. Their hardware return a score, but no PV. So
>>>>sometimes they didn't get a complete PV, and say "the pv COULD BE UP TO ...".
>>>
>>>
>>>
>>>That makes no sense.  They don't limit the 12 ply search to 6 plies of
>>>extensions
>>>total.    So he is not talking about search extensions.   Saying "the PV could
>>>be up
>>>to 6 plies deeper" is _obviously_ not a reference to the missing pv from the
>>>hardware
>>>for many reasons.  First, if the hardware is searching 6 plies, the PV would not
>>>be
>>>"up to 6 plies more" it would be "at _least_ 6 plies more because of the
>>>hardware search
>>>extensions + qsearch".
>>
>>
>>>
>>>
>>>>
>>>>>
>>>>>2.  If 12(6) means 12 plies total, with 6 in hardware, what does 4(5) mean?  4
>>>>>plies total
>>>>
>>>>Uri Blass suggests aggresive extensions that increase the remaining depth.
>>>
>>>Again, that makes no sense in this context.  It would _instantly_ have to resort
>>>to a
>>>hardware-chip only search if the above means 4 plies brute force, 5 plies of
>>>that done
>>>by hardware.
>>
>>I do not see the problem.
>>
>>It is possible that deeper blue extended 4 plies for the first 3 plies so the
>>first 3 plies were done in the software and the last 5 plies were done in the
>>hardware.
>
>Then vincent's 4(5) can't possibly be right either.  Hsu _clearly_ said 4 means
>4
>plies of "brute-force" search.  Whatever the hardware does, it does at _every_
>ply,
>so the 4(5) explanation you are proposing just doesn't fit...

I do not try to defend vincent explanation but to explain how it is possible to
get 4 plies by normal definition when 5 is the maximal depth of the hardware.

Suppose that the software searches in some line 3 plies and the remaining depth
after the 3 plies is 5 thanks to extension.

It means that the normal depth of the search was 4 and the maximal depth of the
hardware was 5.

Uri



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