Author: Peter Fendrich
Date: 14:28:49 01/28/99
Go up one level in this thread
On January 28, 1999 at 15:44:35, Robert Hyatt wrote: >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.. :) The idea isn't that new! Chess 4.5 used what you are describing as early as 1974! They never called it razoring or anything else from what I know. Source: "Chess skill in man and machine", Peter W. Frey, 1977. //Peter
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