Author: Dann Corbit
Date: 13:45:50 01/27/00
Go up one level in this thread
On January 27, 2000 at 16:26:46, Tom Kerrigan wrote: >On January 27, 2000 at 13:17:32, Robert Hyatt wrote: > >>The point is on "what" architecture? 40K on a sparc == 20K on an X86. > >Not really. You have been arguing for a long time that the DB evaluation >function could not be implemented on a PC simply because it is too expensive. My >goal is simply to "prove" that it's not too expensive, and by extension, some PC >programs probably have equal (possibly better) functions. This "proof" doesn't >require the exact number of instructions. FHH's estimate could be off by a >factor of 2, and the function would still not be too expensive. > >>Even more important, is deriving that 40K estimate. It would take a _lot_ >>of thought to come up with a real number, because hardware design doesn't >>translate to "N instructions" trivially. IE I suspect that the number 40K >>is just a big number that was used to illustrate how much stuff DB is doing >>in the hardware chips using parallel circuits. > >I think this theory is deeply insulting to FHH. He has published his estimate in >a well-regarded and widely-read journal, and he didn't give any HINT of a >warning that the estimate has any error at all. By saying that 40k "is just a >big number" you are attacking his professional integrity I don't see any deep, personal insult, and I have written professional, technical papers. Since the term is 40K (a rather round figure) it's pretty obvious that it is an estimate. Now, I doubt very much that it will be off by more than 50% unless you are talking about a chip different that whatever it was Hsu was considering. But we don't even know what that was, do we? >Let's say you're trying to sell your house. You know that your house is pretty >big, so you place an advertisement in the newspaper saying that it's 8 million >square feet. Somebody comes to look at the house and points out that it's >nowhere near 8 million square feet. Would you say, "Oh, yeah, it actually takes >some effort to measure the size of a house, so I just figured I would convey the >impression that it's big." No, you wouldn't say that, because it's lying. And >neither would Hsu. > >I think it would actually be fairly easy to come up with an estimate like this. >You just go through all the terms you have, and imagine how you would implement >them in software. Guess at how many instructions it would take and add >everything up. For example, if you know that finding a doubled pawn takes about >5 instructions, and you think that you could find an isolated pawn the same way, >you can guess that it's another 5 instructions. And so on. I don't think we can extrapolate from an estimate to a wild hyperbole. If Hsu had meant an actual count, he could have said something like: It took 45,132 Intel PII instructions to perform the exact same evaluation for position 'X'. Since it is obviously going to vary enormously from position to position, it *can't* be anything _but_ an estimate. I think (for whatever target chip he had in mind) we can safely assume he was talking about 20-80K instructions. To assume that he must have meant an absolute figure is much more of a stretch than to imagine it to be an estimate. IMO-YMMV.
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.