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Subject: Searching 18-20 ply just using nullmove

Author: Vincent Diepeveen

Date: 18:21:46 08/17/00


Hello,

A few years ago (about 3) i claimed that searching 18-20 ply was possible
with huge hashtables, nullmove, a good evaluation function, and
several billions of nodes.

I was considered nuts by half of the RGCC population, because no
branching factor was capable of being that good, when you would
search deeper, your branching factor would NOT get under 4.0, that
was considered impossible by a lot of people even.

Obviously most people following: "i believe that i see in the ads
or where i see the outputs from", they challenged me. Some went even
that far and called me nuts, a liar and a frog and many other terms.
At RGCC there was room for that and much more which i'll not quote here!

At that time, diep was only a few years old, and i had a small computer
with very little hashtables. Also there were thousands of bugs inside it.

Programs like Schach, crafty and many other programs at that time
were having real bad branching factors around 1997. With billions of
nodes they didn't search deeper as say 12 ply, which was about the depth
Deep Blue searched also at that time. Programs searching a bit
deeper were directly called "forward pruners" referring to forward pruning
other as nullmove.

Since a few days i have a new computer (dual 800),
and since a few hours i have
256mb RAM inside it. Diep is a lot better nowadays, and
the fact that not many people care nowadays about the above statement
as they're used to good branching factors nowadays also, they just
don't care anymore.

Note that the statements were around 1997. Now in 2000 most people
are spoiled with good branching factors and they have usually seen their
own programs get better branching factor also.

At that time programs like schach after searching a full week with
150k nodes a second or so or more, they didn't search deeper as 11 ply
with around 32mb hash.

Now that i have this cool computer, it's time to start to proof the 18-20
search depth. Starting with an output about this cool position Ne4!!
tomorrow morning when it will have searched over a billion of nodes!

Vincent




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