Author: Robert Hyatt
Date: 12:44:35 01/28/99
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On January 28, 1999 at 09:20:23, Ernst A. Heinz wrote: >On January 28, 1999 at 00:24:51, Robert Hyatt wrote: > >>On January 27, 1999 at 16:28:59, Ernst A. Heinz wrote: >> >>>On January 27, 1999 at 16:08:10, Ernst A. Heinz wrote: >>>> >>>> [...] >>>> >>>>Where and why did the term "pruning" get misused in your opinion? >>>> >>>>1. Normal futility pruning (as coined by Jonathan in his Ph.D.thesis), >>>>2. extended futility pruning (as coined by me in the ICCA Journal), and >>>>3. futility pruning in the quiescence search (as done by almost anybody) >>>> >>>>all *cut* (or prune if you like) moves at the nodes where they are applied >>>>according to my above explanation. >>> >>>Just a short addition: "to cut a move" of course means to cut the whole subtree >>>spanned by it. >>> >>>Hence, the only misnomer I can detect is that Peter McKenzie and you denoted >>>a depth reduction as "razoring" although the original term "razoring" as coined >>>by Birmingham and Kent in 1977 clearly r eferred to real pruning by stopping the >>>search completely at the respective nodes (i.e. all moves get cut off). >>> >>>=Ernst= >> >>correct.. and razoring may be the wrong term on my part. I spent a bit of time >>trying to find the most recent article I read on razoring ideas. The 1977 or >>so one I have, but there has been something different. Maybe in one of the >>'synopsis papers' I have in my file and not the JICCA as I thought. >> >>All I know at present is that what I call "razoring" came from something I read >>within the last two years, based on the comments in main.c that indicate about >>when I added it. It wasn't something I developed at all, just something I tried >>and it seemed to work, after seeing someone else write about it. I will >>continue searching for it however.. > >In 1977 Birmingham and Kent also suggested a depth reduction for what they >called "deep razoring". This was meant to apply their normal and already quite >unsound razoring cuts in an even riskier fashion by comparing results of "deep" >searches with static evaluations or shallower searches at nodes far above the >frontier. > >Maybe the misnomer stems from this idea of "deep razoring". > >=Ernst= That's possible... I didn't look back at the 1977 article yesterday, but I definitely got the idea of doing this at 'depth=2' and reducing by 1 ply from somewhere. Wish it was my idea, but it wasn't.. :)
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