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Subject: Re: speedup of cray blitz as published in 1997

Author: Robert Hyatt

Date: 21:38:36 09/24/01

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On September 24, 2001 at 22:30:26, Vincent Diepeveen wrote:

>Hello,
>
>Here written down speedups as claimed by a guy called R. Hyatt
>by cray blitz for 24 different positoins as they occured in
>a game:
>
>pos  speedup
>1     2.0
>2     2.0
>3     2.0
>4     2.0
>5     2.0
>6     2.0
>7     1.9
>8     2.0
>9     2.0
>10    2.0
>11    2.0
>12    1.9
>13    1.9
>14    2.0
>15    2.0
>16    1.9
>17    1.7
>18    1.8
>19    2.0
>20    2.0
>21    2.0
>22    1.9
>23    2.0
>24    2.0
>avg   2.0

Please re-do your math.  No way to average 2.0 with even _one_ value that
is < 2.0

There are several above that are less than 2.0




>
>So YOU, Robert Hyatt, claims in an OFFICIAL magazine,
>called ICCA journal march 1997,
>an AVERAGE speedup of 2.0 with cray blitz at 2 processors.
>

I don't see an average of 2.0...



>Now i claim the same with DIEP if i'm not using dangerous
>extensions (which btw are turned on by default).

No... You claim > 2.0 which is not possible over a set of positions.  Unless
your sequential search is simply badly flawed.  Then it doesn't matter.  Go get
a copy of my Ph.D. dissertation.  I proved quite clearly that for a minimax
search (alpha/beta with worst-possible ordering) it is possible to get a
near-perfect speedup curve.  I also proved that with perfect ordering, the
same is possible.  But The real point was that I clearly proved that we can't
get perfect move ordering (for obvious reasons) so that for normal cases, an
optimal (4.0 using 4 cpus) is not possible.





>
>It appears you hadn't turned them on either (smart guy
>to publish only speedups without dangerous extensions and only
>tell in 2001 that you hadn't turned them on).

I was supposed to tell I hadn't turned on something I was not using because
it caused a serious problem???  I don't follow that logic.  And I don't consider
the SE as "a dangerous extension".  I don't do "dangerous extensions" anywhere
in my code, either now or then...



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