Author: Dann Corbit
Date: 14:44:58 02/11/02
Go up one level in this thread
On February 11, 2002 at 17:35:44, K. Burcham wrote: >On February 11, 2002 at 16:59:11, Dann Corbit wrote: >>On February 11, 2002 at 16:11:15, K. Burcham wrote: >>>On February 11, 2002 at 13:51:31, Dann Corbit wrote: >>>>On February 11, 2002 at 13:22:50, K. Burcham wrote: >>>>[snip] >>>>>Like I said before, if we monitor the cpu usage, and it is 100% on both >>>>>machines, and both programs have same amount of nodes per move posted in >>>>>analysis, then I can conclude that the processor in the larger mhz machine >>>>>is busy doing something---the question was what are some of the tasks that this >>>>>larger mhz machine is doing while running a chess program that do not allow it >>>>>to post more nodes per move? (of course assuming that both systems are not >>>>>burdened with any background software running, or non chess related tasks >>>>>consuming cpu) >>>> >>>>I think I understand your question now. >>>> >>>>Take a slow searcher like MChess -- It might take 10,000 machine cycles to >>>>examine one node. But the work it does perform is throwing away useless >>>>examinations of valueless nodes. >>>> >>>>Another program might examine a node in only 100 machine cycles. But it is >>>>obviously not being nearly as choosy about what it looks at. >>>> >>>>The slow searchers spend more compute power deciding what nodes need >>>>examination. The fast searchers spend less time on that and make up for it with >>>>the increased speed. Two different approaches but both arrive at the same goal. >>>> >>>>Both CPU's are pegged when analyzing for both the slow and fast searcher. But >>>>they are busy computing different things. >>>> >>>>The slow searcher is saying, "Should I bother with this? No. How about that? >>>>No. Maybe this one? Nope... Aha! Here's a good one. I better check it >>>>carefully." >>>> >>>>The fast searcher is saying "Here's one -- check it. Here's one -- check it..." >>>> >>>>Now, even with the fast searcher, it won't blindly examine all the nodes. It is >>>>just that it examines a lot more but is less selective about what it looks at. >>>Dan >>> >>>much better, Dan. but we are still not there yet. are you saying that all lesser >>>moves looked at are not added to the posted node count? >>>lets use your words---The slow searcher is saying, "Should I bother with this? >>>No. How about that? >>>>No. Maybe this one? Nope... Aha! Here's a good one. I better check it >>>>carefully." >>>lets count your example: you had three "no's" and one "good one" for a total of >>>four nodes. are you saying in this example only one node and its variations are >>>added to the posted node count, and the other three nodes and their variations >>>because they were analyzed as a lesser value and at some stage in the analysis >>>were pruned, are not added to the posted node count? >> >>The slow searchers may bypass entire branches of the search tree. The effort >>spent deciding what to discard may be considerable. The actual nodes of a huge >>part of the tree may never be examined. >> >>When the slow searcher says, "Shall I look at this" it may not be considering a >>single board position, but rather a branch of the tree containing 40 million >>nodes. >Dan > >none of your last statements are refering to the intent of my question, except >one (I think). > >"The effort spent deciding what to discard may be considerable." >ok, this statement refers to my question. what work (cpu usage) is the program >doing that is not a board position? what work (cpu usage)is the program doing >that does not include a node? what is taking up processor time with the program >that is not a node? what is using the processor that is not a board posiiton? >please do not say the os, or background os tasks. i am not refering to any of >these, i am aware of these. i am only refering to cpu usage of the program that >is not looking at, considering, thinking about, analysing nodes or a board >position. what about this "effort spent"? what is effort spent if it is not a >node or board position. other than book moves, and using egtb, what else does a >program do to use cpu other than nodes or board posiitons? >of course to me all that i have said, and all these questions are looking for >only one answer. > >It is difficult to be curious about a subject, and not have enough knowledge >about the subject, to phrase a question on a level, so as to obtain a >satisfactory answer from one you feel has the ability to form the level of >answer that one thinks he is looking for. >I am also concerned about this topic being too trivial for the length of this >thread. maybe this should have been e-mail? Unfortunately, your questions don't have simple answers. http://www.gamedev.net/reference/programming/features/chess3/page2.asp http://www.dcs.qmul.ac.uk/~icca/anatomy.htm#tree%20searching http://citeseer.nj.nec.com/451147.html http://www.csis.hku.hk/~kpchan/cs23270/3.problem-solving/gametree.html http://www.cs.toronto.edu/~mitchell/ai-course/gp.html http://www.ast.cam.ac.uk/~cmf/chess/theory.html http://www.seanet.com/~brucemo/topics/topics.htm
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