Computer Chess Club Archives




Subject: Re: Everything you know is wrong

Author: Sune Fischer

Date: 05:29:17 12/18/02

Go up one level in this thread

On December 18, 2002 at 07:47:01, Vincent Diepeveen wrote:

>Right he has wrongly split it in order to avoid even the worst proofreader
>from smelling the truth.

Or to hide the real truth, that it stabilises the search and will be really
really great in games :)

>>First he designs an algorithm to make a smaller tree and then he verifies that
>>it's also better (solving more positions).
>In neither of the 2 tests the algorithm is superb. So he could not
>draw the conclusion that verification search is better. *no way*.

IIRC the conclusion was that it was better than R=2 and that R=2 was better than
R=3. Nothing more, nothing less.

>>Those are very though demands, you _can_ get an overall improvement by say,
>>searching 5% more nodes but in return get far less instability in your search.
>He doesn't hash whether he has done a verification, so his implementation
>for sure is buggy. I wonder why proofreaders didn't see that.


>>Such an improvement wouldn't never be discovered by this method, because more
>>nodes is bad _by definition_.
>Not always. time to solution counts. Nothing else counts.
>Of course there is other conditions that must be satisfied too
>like testing at the same machine.
>If i do not nullmove in DIEP at 1 ply depthleft, then diep needs less
>nodes to complete a search, but more time. Number of nodes is trivially
>bad way to measure things when we talk about nullmove and such methods
>that all put stuff into the hashtable.
>Nothing as cheap as a hashtable transposition. Just like 500 clocks or
>so. There is plenty of other algorithmic changes to figure out which
>reduce number of nodes and increase time to search. Good other example of
>what decreased my node count *considerably* but is just too expensive
>too do is ordering at every position in the main search all moves based
>upon evaluation of the position after it (of course also using a SEE
>with it in combination). So ordering it by evaluation.

There are several ways to do this research.
You are the end user, you don't care about the photoelectic effect, you just
want your television to work.

What Omid here is showing, is that if you do this, or if you do that, then this
will happen to the node count.

Secondary, did it _improve_ the program?

You can do a not-very-scientific-but-highly-user-orientated-paper on "if you
have a top notch program with a low branch factor and very good search and all
the prunings and extensions you can think of, then this method X is good..."

Tell me you don't see a problem with that kind of article?

>Even if i do not do that at depthleft == 1 ply, then it is slowing me
>down a factor 2 or so nearly but it reduces node count with around
>30% or so?

I suggest you do a paper on:
"Heavy use of evaluation will lower branch factor".

That's perfectly fine, only thing is that it is a bit obvious and has been done
by everybody. However, there might be a paper in it somewhere, if you eg.
examine things like, is there diminishing returns on more evaluation? With all
the knowledge in Die this might actually be a very relevant question to you.


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