Author: Andrew Williams
Date: 12:50:18 07/29/03
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On July 29, 2003 at 14:58:48, Tord Romstad wrote: >On July 29, 2003 at 05:42:11, Andrew Williams wrote: > >>On July 29, 2003 at 05:38:20, Tord Romstad wrote: >> >>>I am currently experimenting with MTD(f). There are still a few bugs left >>>to fix, but it mostly seems to be working OK now. However, there is one thing >>>I haven't been able to figure out: >>> >>>Is there an easy way to store the PV in MTD(f)? Currently I just construct a PV >>>from the hash table after each iteration. This works, but is somewhat messy and >>>inconvenient. Is there a better way to do it? >>> >>>Tord >> >>Hi Tord, >> >>I do as you do, and extract the PV from the hash table. Some time ago, a guy >>called Fabien Letouzey appeared here with an alternative suggestion: >> >>http://fortuna.iasi.rdsnet.ro/ccc/ccc.php?expr=&subject=&author=letouzey&email=&nr=50 >> >>I've never tried it. > >Thanks. If building the PV from the hash table is good enough for you, I >think I'll keep doing it like that myself (with Tony Werten's suggested >improvements), and take a closer look at Fabien Letouzey's suggestion >when my mtd(f) is good enough to be usable. > >There is still a long way left before mtd(f) works as well as traditional >aspiration search in my program, but I will continue trying for some time. >mtd(f) is fun and addictive. :-) > >Tord Yes. There's just so much scope for experimentation. For example, in Aske Plaat's online description, he raises and lowers the guess by 1 each time around the MTD loop. I've never been able to make this work effectively. Far better to accelerate this. If the score is going up, I add 1 the first time then 2, then 3 etc etc. I think I stop at 7 or something. I can't remember now. The same applies to when the score is sinking. Have you read Aske Plaat's PhD thesis? It's available online somewhere and is very interesting and readable. AW
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