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Subject: Re: Verified Null-Move Pruning, ICGA 25(3)

Author: Vincent Diepeveen

Date: 18:21:09 11/21/02

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On November 20, 2002 at 17:51:40, Alessandro Damiani wrote:

'verified' nullmove, or in a different implementation but
same algoritm, with just 1 ply reduction is nearly a fullwidth

I did with a bigger reduction of course. that's also very
costly compared to R=3. This was just an experiment carried
out years ago when it was described in ICCA journal. Now
we have same algoritm in a few lines diff algorithm.

I do not see how Omid can just suffer 50% slowdown of his
algorithm. Note he only publishes search depths not
search times. That is wrong.

You must publish search times.

I suffer plies if i reduce just 1 ply.

R=2 or R=3 is irrelevant to that.

>>One final remark: You use standard R = 3 in DIEP. So the search tree constructed
>>by your program will definitely be smaller than that of verified R = 3. Many
>>people find standard R = 3 as too risky; but if you are happy with its overall
>>tactical strength, then I don't recommend you to shift to another method. But
>>for those who'd like to get greater tactical strength than standard R = 2, and a
>>smaller search tree than R = 2, I recommend to try verified null-move pruning.
>Vincent uses R = 3 and complex quiescence search (Vincent, correct me if I am
>wrong). Maybe your Verified Null-Move gives about the same results like R = 3
>with a complex quiescence search.
>_If_ this is true then your approach is simpler and therefore better. Just my
>two thoughts before going to bed. Good nights.......

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