Author: Robert Hyatt
Date: 17:44:36 01/28/99
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On January 28, 1999 at 17:28:49, Peter Fendrich wrote: >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 something wrong with the above. First chess 4.0 played its first game in 1976. At the Houston ACM... I was there. Second, it didn't do any of this razoring at the time, and my "chess skill" book doesn't mention such as all in the context of their program... they did an out-of-check extension, null move was unknown, and I didn't see any reference to razoring at all. I think I still have their source code so I could check, but my COMPASS (CDC assembly language) is somewhat rusty...
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