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

Author: Uri Blass

Date: 12:02:57 10/18/02

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On October 18, 2002 at 14:59:09, Robert Hyatt wrote:

>On October 18, 2002 at 03:11:41, Uri Blass wrote:
>
>>On October 18, 2002 at 00:00:17, Robert Hyatt wrote:
>>
>>>On October 17, 2002 at 20:50:55, Uri Blass wrote:
>>>
>>>>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
>>>
>>>We know some specifics.  We know that the hardware didn't do 1-2 ply searches.
>>>It couldn't
>>>because it finished so quickly the SP2 couldn't keep up.  Therefore, this still
>>>doesn't work...
>>
>>In the example that I give the hardware did 5 plies search
>>and not 1-2 ply search so I still do not see the problem.
>>
>>It is possible that 5 plies is the maximal depth and
>>there were also cases
>>when the software asked the hardware to do 4 ply search
>>but not 1-2 ply search.
>>
>>Uri
>
>
>OK, then again tell me how 4(5) is going to always let the hardware do 5 ply
>searches
>(which I don't believe by the way as he said "up to 5 plies in hardware"
>recently) with only
>4 plies of brute-force search.  You can _not_ assume that there are extensions
>in the brute
>force search because in many positions, there are none...

I did not say that 4(5) is going to always let the hardware do 5 ply searches.
doing 5 plies search in part of the cases when in another part of the cases you
do 4 ply search is enough.

Uri



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