Author: José Carlos
Date: 11:23:28 09/07/02
Go up one level in this thread
On September 07, 2002 at 12:46:22, Rolf Tueschen wrote: >On September 07, 2002 at 10:08:18, José Carlos wrote: > >>On September 07, 2002 at 06:26:30, Rolf Tueschen wrote: >> >>>On September 07, 2002 at 03:34:55, José Carlos wrote: >>> >>>>On September 06, 2002 at 21:42:17, Robert Hyatt wrote: >>>> >>>>>On September 06, 2002 at 16:26:14, Rolf Tueschen wrote: >>>>> >>>>>>On September 06, 2002 at 15:55:09, Robert Hyatt wrote: >>>>>> >>>>>>>On September 06, 2002 at 15:41:41, Rolf Tueschen wrote: >>>>>>> >>>>>>>>On September 06, 2002 at 15:28:09, Sune Fischer wrote: >>>>>>>> >>>>>>>>>On September 06, 2002 at 14:38:15, Robert Hyatt wrote: >>>>>>>>> >>>>>>>>>>On September 06, 2002 at 14:17:59, Sune Fischer wrote: >>>>>>>>>> >>>>>>>>>>>On September 06, 2002 at 11:53:13, Robert Hyatt wrote: >>>>>>>>>>> >>>>>>>>>>>>I have posted the raw data logs, the "cooked data" that I extracted from the >>>>>>>>>>>>logs, and the speedup tables (those for Martin last nite). It might be >>>>>>>>>>>>interesting to take the cb.c program I also posted and change the speedup >>>>>>>>>>>>format to show 3 decimel places (I used 2 as Martin had suggested that would >>>>>>>>>>>>be better.) >>>>>>>>>>>> >>>>>>>>>>>>It would be interesting to run the program with 1, 2 and 3 decimel place >>>>>>>>>>>>accuracy, and let everyone look at the three tables and decide which one >>>>>>>>>>>>_really_ provides the most useful information. I'll bet everyone likes >>>>>>>>>>>>.1 better than .11 because is .01 really significant? Or is it just random >>>>>>>>>>>>noise? >>>>>>>>>>> >>>>>>>>>>>To a numerical scientist (as I'm sure you know) the numbers 1.8 and 1.80 are not >>>>>>>>>>>identical, 1.80 is ten times more accurate, and that is a powerful statement in >>>>>>>>>>>itself. >>>>>>>>>>>To produce such a number you need to (a) run a larger experiment and do some >>>>>>>>>>>statistics to get an average or (b) get some better and probably a lot more >>>>>>>>>>>expensive equipment (higher resolution mass-spectrometers, or whatever the >>>>>>>>>>>situation may call for), though in this case (a) seems like the only option. >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>>(a) was the course I took in my dissertation, but I had a 30 processor >>>>>>>>>>sequent that was basically "mine" for several months so running thousands >>>>>>>>>>of tests was not impossible. >>>>>>>>>> >>>>>>>>>>However, doesn't that leave the data open to the same criticism as the data >>>>>>>>>>in my dts JICCA article? (that the data is not "raw")?? Because it will >>>>>>>>>>be an average, and that will make it look artificial... >>>>>>>>>> >>>>>>>>>>So back we go again? >>>>>>>>> >>>>>>>>>Sorry, I'm not fully up to speed here because I haven't read all of the threads, >>>>>>>>>so my comment was more of a general nature :) >>>>>>>>> >>>>>>>>>But I'd say it depends on what you want to show, if you have bunch of positions >>>>>>>>>that you want to know the speedup for, and you know that every time you run it >>>>>>>>>you get something sligthly different. Then, you have no choice but to roundoff >>>>>>>>>to lose a few of the inaccurate digits, or alternatively do additional work to >>>>>>>>>make sure you get the digits right. >>>>>>>>> >>>>>>>>>There seems to be little point in using a number of 1.983432 for a speedup, if >>>>>>>>>the next run will produce 1.9348284 and the next 1.96347823 etc., it looks >>>>>>>>>rather silly doesn't it :) >>>>>>>>> >>>>>>>>>Personally I would rather be presented with a clean average number of 1.94, or >>>>>>>>>even 1.9 or 2.0. >>>>>>>>> >>>>>>>>>>I've always used "averages" but for the DTS paper it was simply impossible. >>>>>>>>>>You might Call someone up like say "united computing" in texas and ask what >>>>>>>>>>they would have charged for a few months time on a dedicated C90. :) >>>>>>>>> >>>>>>>>>That is a dilemma, of course if you have no grasp what so ever on how much the >>>>>>>>>error is, you have a problem. So to be safe, it is better to use less digits ;) >>>>>>>>> >>>>>>>>>Anyway, this is all something that can be read in any introductury data analysis >>>>>>>>>book, here is something I found on google: >>>>>>>>> >>>>>>>>>"From the mathematical standpoint, the precision of a number resulting from >>>>>>>>>measurement depends upon the number of decimal places; that is, a larger number >>>>>>>>>of decimal places means a smaller probable error. In 2.3 inches the probable >>>>>>>>>error is 0.05 inch, since 2.3 actually lies somewhere between 2.25 and 2.35. In >>>>>>>>>1.426 inches there is a much smaller probable error of 0.0005 inch. If we add >>>>>>>>>2.300 + 1.426 and get an answer in thousandths, the answer, 3.726 inches, would >>>>>>>>>appear to be precise to thousandths; but this is not true since there was a >>>>>>>>>probable error of .05 in one of the addends. Also 2.300 appears to be precise to >>>>>>>>>thousandths but in this example it is precise only to tenths. It is evident that >>>>>>>>>the precision of a sum is no greater than the precision of the least precise >>>>>>>>>addend. It can also be shown that the precision of a difference is no greater >>>>>>>>>than the less precise number compared. >>>>>>>>> >>>>>>>>>To add or subtract numbers of different orders, all numbers should first be >>>>>>>>>rounded off to the order of the least precise number. In the foregoing example, >>>>>>>>>1.426 should be rounded to tenths-that is, 1.4." >>>>>>>>> >>>>>>>>>http://www.tpub.com/math1/7b.htm >>>>>>>>> >>>>>>>>>(some great semantics at the very bottom:) >>>>>>>>> >>>>>>>>>-S. >>>>>>>> >>>>>>>>Chapter three: >>>>>>>> >>>>>>>>Bob, how you could say that speed-up was measured? Isn't it a factor and >>>>>>>>therefore calculated? come back to my first statement! >>>>>>>> >>>>>>>>Rolf Tueschen >>>>>>> >>>>>>> >>>>>>>OK... a terminology issue. Board A is 2 feet long. Board B is 3 feet long. >>>>>>>How long are both? >>>>>>> >>>>>>>measured: put 'em end to end and let a tape show 5'??? >>>>>>> >>>>>>>calculated: measure each one and add the two lengths which shows 5'??? >>>>>>> >>>>>>>The speedups were calculated, but there is an exact relationship between the >>>>>>>time taken to search with 1 processor vs the time taken to search with N >>>>>>>processors. Speedup is defined to be that ratio. IE the speedup was not >>>>>>>extrapolated, or calculated by finagling with various things like NPS, time, >>>>>>>outside temp, cpu mhz, etc. It is just a direct result of dividing measured >>>>>>>number A into measured number B. >>>>>>> >>>>>>>Whether that quotient is "measured" or "calculated" seems to be moot since it >>>>>>>will be the _same_ result...??? >>>>>> >>>>>>I'm getting older each day... >>>>>> >>>>>>But speed-up is a factor and _not_ seconds. Ok, this might be unimportant here. >>>>>>We're surely not searching for Newton's constants. Since we are depending on >>>>>>chess positions as you've said yourself. So we can't have 'exact' relationships. >>>>>> >>>>>>Rolf Tueschen >>>>> >>>>> >>>>>Here we do. IE, the one cpu run takes two minutes. The two cpu run takes >>>>>one minute. The speedup is 2.0, which is produced by dividing the 1cpu time >>>>>by the 2cpu time. In fact, that is the only way to get a speedup since you >>>>>really can't "observe" such a thing in raw form because it is a comparison >>>>>between two separate events... >>> >>>> >>>> Another example, in case someone still is confused about this, is "raw NPS" >>>>(which most people accept without problem). You don't meause NPS directly, you >>>>measure total nodes and time, and then calculate a ratio. Exactly the same as >>>>the speedup ratio. >>> >>>Interesting how some are trying to fish in no man's land. >> ^^^^^^^^^^^^^^^^^^^^^^ >> >> Would you be so kind to explain the undelined expression? I'm no native >>english speaker. And when you explain it, will you please say if you mean I'm >>doing that, whatever it is and why? >> Thanks. > >I'm not an English writer either. I mean speaker. Yes, what I was trying to do >was lifting your basic idea onto more literary level. What poets are doing in >general. You said, that someone could be confused although most people would >accept it without problem. I'm afraid I didn't express myself properly then. The two statements were related to different things: "confused" about the concepts of measured / calculated / extrapolated and "accept without problem" about the NPS figure. >That little idea of contrast brought me to the >lyrical picture of a man fishing in no man's land. It might have a biblical >background as well because where today is wasteland yesterday there could >be the sea (with enough fish)... > > >> >>>But Bob is too smart to utilize such tricks. >> >> Would you be so kind to explain what tricks are you reffering to and if you >>mean I'm using them and why? >> Thanks. > >Youre welcome. Since I'm not a clairvoyant I'm not able to tell you why you are >using such nice ideas. I'll rephrase my questions for you can answer easily: a) what tricks are you reffering to? b) do you mean I'm using them? c) why do you say such a thing? >>>While some always fall into their self-made traps. >> >> Would you be so kind to tell me if you mean I made some traps and fall into >>them, what traps are they and why do I fall into them? >> > >Two things.First I observe that your English is a bit similar to the >routines in chess programming, the long repetitions in expressions. If you were so kind to tell me what expressions I often repeat that'd be a nice help on improving my english. >I like that because it helps when you're reading it. You can concentrate >on the important parts of the message. Second. If you are a chessplayer >you surely had the experience to fall into some trap. Sure, many times, I'm afraid. That's part of the fun of chess. >But surely not allplayers fall. I think all players fall in traps sometimes. There's no perfect player. I remember Tal used to say he like to fall into traps, just to sit there and find a way out... >Therefore I used the restricting "some" which I read in your former post. You should forgive my lack of understanding here, but either you didn't answer my question at all or I missed the answer. Here it is again: >>>While some always fall into their self-made traps. >> >> Would you be so kind to tell me if you mean I made some traps and fall into >>them, what traps are they and why do I fall into them? And rephrased: a) do you mean I made some traps? b) what traps? c) do you mean I fell into them? d) where in my post do you read something that shows I'm falling into them? >>>Always. The "most people accept without problem" will become a real classic. >> >> Would you be so kind to tell me if you're being ironic when using the word >>"classic" and why? > >I made a serious prediction. Interesting. Is your prediction related to a certain context or is it a general prediction? >>>Too much unintentional confession in five words. >> >> Would you be so kind to explain me what confession I'm doing with those five >>words? > >Here I must have still stood under the impression of your praised 'idea' >above. Unintentional confession is such a literary transposition I like. Well, it's not an idea, but an example. As for my question, you didn't answer. What confession am I doing with those words? >>>The opposite of smartness... >> >> Would you be so kind to tell me if this is meant to be an insult against my >>intelligence and why? > >No, here you are on a tangent. You must read the German Tarrasch explaining >the medical problems that could lead to the behaviour that a chessplayer >falls into a trap, alien or own trap. I'm not known for insults with medical >background. Since I am working myself in a part of medical care. I never laughed when someone fell into a trap in chess. The point of Tarrasch was that >even highly intelligent people fall into a trap sometimes. So what's the meaning of your "The opposite of smartness..." >> >>>Rolf Tueschen >> >> This was my first post in all of this confusing topic. I have read most >>of the posts but I felt I didn't have enough information to make an >>opinion, so I kept respectfully silent. Now I think I have an opinion, but >>I don't think it's worth it to get into the hot discussions. >> Then I see this raw data vs calculated data vs extrapolated data, I >>decide to post an example to help clarifying the concept of calculated >>from raw data. My post is not directed to anyone, as shown by the fact >>that it follows a post from Bob. No offense to anyone. Just one more example. > >"Shyness is the grafting of the dignity of man." I forgot who made this famous >idiom! But beware that it takes possession of you! Would you please explain the meaning of this? I'm not bad at poetry when it's in spanish, but in english I have no chance. >Best wishes for the weekend Same to you. José C.
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