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Subject: Re: move_generation + hash

Author: Ed Schröder

Date: 12:24:36 05/30/00

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On May 30, 2000 at 00:28:47, Robert Hyatt wrote:

>On May 28, 2000 at 16:37:32, Gian-Carlo Pascutto wrote:
>
>>On May 28, 2000 at 10:02:05, Georg v. Zimmermann wrote:
>>
>>>From my tests it shows that it sticks with the hash-move about 50% of the time.
>>>Should this number be higher ?
>>
>>Hmm...if this number is also effectively your 'move ordering percentage',
>>which I assume it is, it is quite low. I'd expect it to be at least about 75%.
>>
>>>
>
>
>
>The classic definition of a "strongly-ordered tree" is this:  If, for every
>node where you fail high, you fail high on the first move at least 90% of the
>time, then your move ordering is good."  If you are much below 90% and already
>have a serious problem that is not hard to fix.  The traditional ordering ideas
>holds Crafty at 92% and better for most of the game.

I can't understand the 92%. A perfect mini-max search requires many many
nodes an alpha-beta cutoff will not work and you are forced to search all
the nodes of the ply in question. And this number is certainly much higher
than 8%.

The way I count is to calculate the percentage around the alpha-beta check.
I get 65 to 70% and this number is pretty stable for each position I tested.
So the question is how you count, and your interpretation of a fail-high.
When I read fail-high I interprete this as a normal alpha-beta cutoff check.

Ed



>>>I was very dissapointed when I didn't notice any speedup after my changes. What
>>>speedup should I expect ? Something like 0.5-1% or more like 1ply ?
>>>
>>>Am I doing something wrong or does this simply not matter as much as I thought ?
>>
>>It's strange. I did the same thing in the past and arrived at the same result.
>>My eval is pretty small, my movegen is very expensive yet my speed was hardly
>>any better. I didn't get it. I still don't.
>>
>>I still don't get how some programs run 10x as fast as mine either.(Little
>>Goliath). What the hell do they do to make those things so darned fast?
>>
>>--
>>GCP
>
>
>Easy:  Never do now, that which you can defer doing until later.  Because if you
>defer doing it, a cutoff will mean you don't do it at all.



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