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Subject: Re: question about fruit future plans

Author: Steve Maughan

Date: 14:29:54 09/27/05

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Tord,

Good to hear from you.

>Using double bounds is not at all unusual.  I am fairly sure almost all MTD
>engines use them,

Sure - I wasn't thinking of MTD engines.

>including both of mine (the old Gothmog and my most
>recent Glaurung development version, which also uses MTD).

Interesting!  Is there any particular reason for switching back to MTD other
than curiosity?  What are your findings?  Are you going to stick with MTD or go
back to PVS?  Have you started on your re-write of Glaurung?

>Both of them solve Fine70 instantly.  Double bounds are less common in PVS
>engines, but I know there are a few who use them (I don't remember any names,
>though).
>
>You make it sound like using two bounds is a very radical and
>fundamentally different way to use a transposition table, but it isn't.

I haven't come across that much literature on double bound transposition tables.
 I must say they intrigue me as I think the gap between the bounds could (in
some cases) be used to shape the tree i.e. extend or prune.  I plan to play
around with double bounds with Monarch when I get the chance.

[snip]

>I personally think Fruit's problems are entirely unrelated to using two
>bounds, but I wouldn't bet on it.

I think it may be the double bounds since Fruit 1.0 and 1.5 both solve Fine 70,
double bounded trans tables were added in Fruit 2.0 and really Fine 70 is all
about transponsition table usage - but, like you, I wouldn't bet on it.  To
confuse the issue further Toga 1.0 solves Fine 70 with no problem.

I also was not aware that Fabian thinks it's a bug in the search.

Regards,

Steve



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