On Mar 3, 3:38=A0pm, Anton Erasmus <nob...@spam.prevent.net> wrote:> unfortunately it is quite a common tendency to equate accuracy and > precision.It is almost impossible to explain the difference to "the man in the street". Also, have you ever tried to explain the difference between "heat" and "temperature" to the average man in the street? Or "weight" vs "mass"? I once made the mistake of remarking casually that walking on hot coals is facilitated by the fact that hot charcoal, while at a high temperature, contains very little heat [implication: as compared to the specific heat capacity of water in your feet]. Everyone around me smirked and said "Did you hear what nonsense you just said? Very hot but has little heat?" I gave up after ten minutes of trying to explain the difference.
quieries related to math handling in micro controllers
Started by ●February 29, 2008
Reply by ●March 3, 20082008-03-03
Reply by ●March 3, 20082008-03-03
larwe wrote:> On Mar 3, 3:38 pm, Anton Erasmus <nob...@spam.prevent.net> wrote: > >>unfortunately it is quite a common tendency to equate accuracy and >>precision. > > It is almost impossible to explain the difference to "the man in the > street". Also, have you ever tried to explain the difference between > "heat" and "temperature" to the average man in the street? Or "weight" > vs "mass"?Oh, yes. "Current" and "Voltage" indeed are the same things, too.> I once made the mistake of remarking casually that walking on hot > coals is facilitated by the fact that hot charcoal, while at a high > temperature, contains very little heat [implication: as compared to > the specific heat capacity of water in your feet]. Everyone around me > smirked and said "Did you hear what nonsense you just said? Very hot > but has little heat?" > > I gave up after ten minutes of trying to explain the difference.Once I tried to order the PAL/SECAM convertor. They were trying to sell me a 220V/120V transformer instead. It was a sincere and complete misunderstanding. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●March 3, 20082008-03-03
On Mon, 03 Mar 2008 22:38:59 +0200, Anton Erasmus <nobody@spam.prevent.net> wrote:>On Sun, 02 Mar 2008 13:44:12 -0500, Spehro Pefhany ><speffSNIP@interlogDOTyou.knowwhat> wrote: > >>On Sun, 02 Mar 2008 19:49:46 +0200, the renowned Anton Erasmus >><nobody@spam.prevent.net> wrote: >> >>>On Sat, 01 Mar 2008 18:27:15 -0500, Spehro Pefhany >>><speffSNIP@interlogDOTyou.knowwhat> wrote: >>> >>>>On Sat, 1 Mar 2008 13:01:39 -0800 (PST), the renowned GMM50 >>>><gfm5050@gmail.com> wrote: >>>> >>>>>On Feb 29, 5:28 am, "yasha" <yasha...@gmail.com> wrote: >>>>>> hello folks.. >>>>>> I'm doing a project related to 8051 micro controller, it is required to >>>>>> handle floating point numbers to a great precision. >>>>>> is there any way with which this can be done easily with 8051 or is there >>>>>> any mathematical controller that can do a better job? >>>>>> please let me know.. >>>>>> >>>>>> regards, >>>>>> yasha... >>>>> >>>>>Easily??? I'm not so sure. I've written super math packages for >>>>>8051. Lots of testing required. >>>>>Get a good C compiler and see if the double implementation is good >>>>>enough for you. >>>>> >>>>>There are/were floating point math coprocessors but precision was >>>>>about the same as double in C if I remember correctly. >>>>> >>>>>Do you need all the functions in a FP math package or just a few? >>>>>If just a few consider BCD. There are some BCD C libraries in the C >>>>>users group I believe. >>>>> >>>>>Interesting that no one has answered your question directly. >>>> >>>>I am doing a project related to nylon. It's required to handle rope of >>>>great length. Can this be done with nylon rope or or there some other >>>>kind of long rope that will do a better job? >>>> >>> >>>If you use a 32 bit integer to represent lengths in mm, then you can >>>represent a maximum length of 4294967 meters >> >> >>Eh? 2^32-1 = 4294967295 > >Yes that is in millimeters. Divide by 1000 to get meters, which gives >4294967 meters.4294967.295 If you can avoid the case of a zero length rope, maybe you can get to 4294967.296>>>with a precision of 1mm. >> >>+/- 0.5mm > >I did not say accuracy of 1mm. One can have an accuracy of +- 1m, and >still have a precision of 1mm. It is of course silly to do this, but >unfortunately it is quite a common tendency to equate accuracy and >precision.It's marketing-speak.>[Snipped] > >Regards > Anton ErasmusBest regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Reply by ●March 3, 20082008-03-03
In article <13cd0621-4dee-4157-9778-c1d08a111699 @c33g2000hsd.googlegroups.com>, larwe says...> On Mar 3, 3:38�pm, Anton Erasmus <nob...@spam.prevent.net> wrote: > > > unfortunately it is quite a common tendency to equate accuracy and > > precision. > > It is almost impossible to explain the difference to "the man in the > street". Also, have you ever tried to explain the difference between > "heat" and "temperature" to the average man in the street? Or "weight" > vs "mass"?Yes actually. I'm usually fairly successful with heat and temperature. The example of the air in an oven vs the roasting pan usually works fairly well. Whether it sticks for more than 1/2 hr is another question. Speed and velocity on the other hand.....> I once made the mistake of remarking casually that walking on hot > coals is facilitated by the fact that hot charcoal, while at a high > temperature, contains very little heat [implication: as compared to > the specific heat capacity of water in your feet]. Everyone around me > smirked and said "Did you hear what nonsense you just said? Very hot > but has little heat?" > > I gave up after ten minutes of trying to explain the difference.I do believe some people actually work to avoid knowledge, especially if it involves the physical sciences. Robert -- Posted via a free Usenet account from http://www.teranews.com
Reply by ●March 3, 20082008-03-03
In article <p2oos3p7uuaj4p9euitirdfcv6vdlb52m8@4ax.com>, Anton Erasmus says...> I did not say accuracy of 1mm. One can have an accuracy of +- 1m, and > still have a precision of 1mm. It is of course silly to do this, but > unfortunately it is quite a common tendency to equate accuracy and > precision.What's distressing is how many technical people don't seem to understand the difference. Robert -- Posted via a free Usenet account from http://www.teranews.com
Reply by ●March 3, 20082008-03-03
In article <MPG.2236516b6b6ad244989887@free.teranews.com>, sub2 @aeolusdevelopment.com says...> In article <p2oos3p7uuaj4p9euitirdfcv6vdlb52m8@4ax.com>, Anton Erasmus > says... > > I did not say accuracy of 1mm. One can have an accuracy of +- 1m, and > > still have a precision of 1mm. It is of course silly to do this, but > > unfortunately it is quite a common tendency to equate accuracy and > > precision. > > What's distressing is how many technical people don't seem to understand > the difference. >A physics instructor many years ago explained it like this: If you measure the temperature of a pan of boiling water 100 times and the standard deviation of the readings is 0.1 degrees, your thermometer is reasonably precise. If the mean temperature you measured is not 212.0 deg F, the thermometer is not very accurate. There followed a discussion of the factors that might affect the boiling temperature of water. In other words: Precise instruments give you a consistent answer, accurate instruments give you the correct answer. You can calibrate a precise instrument at intervals to give you an accurate answer. It takes a bit more work for each measurment to get the correct answer from an imprecise instrument. Mark Borgerson
Reply by ●March 4, 20082008-03-04
larwe <zwsdotcom@gmail.com> writes:> On Mar 3, 3:38=A0pm, Anton Erasmus <nob...@spam.prevent.net> wrote: > > > unfortunately it is quite a common tendency to equate accuracy and > > precision. > > It is almost impossible to explain the difference to "the man in the > street". Also, have you ever tried to explain the difference between > "heat" and "temperature" to the average man in the street? Or "weight" > vs "mass"?It's not only the man in the street. Even supposedly knowledgeable people have major disagreements as to mass vs. weight. Then you can compound the disagreement by trying to define force and/or impact.> I once made the mistake of remarking casually that walking on hot > coals is facilitated by the fact that hot charcoal, while at a high > temperature, contains very little heat [implication: as compared to > the specific heat capacity of water in your feet]. Everyone around me > smirked and said "Did you hear what nonsense you just said? Very hot > but has little heat?" > > I gave up after ten minutes of trying to explain the difference.
Reply by ●March 5, 20082008-03-05
>It is almost impossible to explain the difference to "the man in the >street". Also, have you ever tried to explain the difference between >"heat" and "temperature" to the average man in the street? Or "weight" >vs "mass"?This comes from the common practice of making scientific deinitions of common terms that turn out to me more precise than those terms. E.g., spiders are not bugs, whales are not fish, Pluto is not a planet.>> unfortunately it is quite a common tendency to equate accuracy and >> precision.just my $0.0200 worth. -- mac the na�f
Reply by ●March 6, 20082008-03-06
Alex Colvin wrote:>> It is almost impossible to explain the difference to "the man in the >> street". Also, have you ever tried to explain the difference between >> "heat" and "temperature" to the average man in the street? Or "weight" >> vs "mass"? > > This comes from the common practice of making scientific deinitions of > common terms that turn out to me more precise than those terms. E.g., > spiders are not bugs, whales are not fish, Pluto is not a planet. >I think you meant "spiders are not insects" - in general usage, even amongst biologists, spiders *are* bugs. Very technically, "bug" refers to the hemiptera insects (these are sap-sucking insects). But more commonly, "bug" refers to arthropods in generally - and that includes spiders, centipedes, and other such creatures. Lobsters and crabs are also arthropods, but probably not what most people mean by "bugs".>>> unfortunately it is quite a common tendency to equate accuracy and >>> precision. > > just my $0.0200 worth. >
Reply by ●March 6, 20082008-03-06
