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#151




There is no rounding needed to represent 0.1 nautical mile, but there is to represent 0.1km? Refuckingally?
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#152




It's said that if we brought together the world's most intelligent people and tasked them with designing the most confusing system of time keeping imaginable, this would still be easier to understand than the system in use today ... just saying ...

#153




Quote:
The ENTIRE metric system is based on division by a number that is not representable in binary floating point. DIVISION and multiplication BY powers of 10 IS THE ENTIRE BASIS OF THE METRIC SYSTEM. Please to not change my point from that, and I should just quit responding to these posts as I am just adding to thread drift. I apologize to the board. Last edited by rat avatar; 07162018 at 02:12 PM. 
#154




There is a reason to use division by 10 in a traditional measurement system if you ever write down or input a number as a decimal. If you ever input 7.3 miles, or 1.2 feet, then you have just input a number that doesn't have an exact binary representation.
The only way around this is if your system is constrained to only accept inputs with fractions in the form of x/(2^y). But your system probably just accepts decimal inputs, and doesn't reject inputs like 7.3 miles, or 4.71 pounds. So then what? Yes, if you accepted inputs, not in decimal but in hexadecimal, then you'd get exact representations of every finite input. But while this is easily possible to imagine and implement, the problem is that your human users will have to be trained to input hexadecimal numbers, and this is a very difficult thing to force them to do. If you're trying to avoid floating point errors this is one way, but then you're introducing the problem of input errors when they make mistakes when converting their inputs to hex. In the real world, we use decimal numbers even for traditional measures like feet, miles, pounds, and hogsheads. 


#155




If you use singleprecision floating point numbers, then the fact that none of your numbers has an exact binary representation results in an imprecision of about one part in a million. Usually, this doesn't matter at all, no matter what the cause of that one PPM error. But in the off chance that it does matter, you can instead use double precision floating point numbers (which are the default nowadays anyway, just because computing is so cheap), in which case your error is about one part in a trillion. I defy you to come up with any application at all where that's not good enough. And even if you are working in the one singular application (yes, that's meant literally) where even that much precision isn't enough, you can get higherprecision floatingpoint packages that will still work.

#156




Quote:
That way you get all the convenient divisors of 12 (halves, thirds, fourths, sixths, twelfths), plus 200 years ago, there was a lot less math and science to convert to base 12.
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#157




Quote:
So the answer is, don't do that. Don't make checks on floating point numbers where the value has to be an exact value, because if you ever once do division by a number that is not 2^n, you will not get an exact binary value. 
#158




The great advantage of the US/UK system is that very few units get divided by 3 easily (feet, particularly. Aside from that, the numbers are incredibly arbitrary and have to be memorised. 1760 yard to a mile is ridiculous unless dividing by 11 is a common ocurrence. However, for everyday life, they are perfectly easy to use.
Here in Perú, an SI country, we still have non SI units in common use. Gasoline is in US gallons (but LPG and LNG in liters and cubic meters) Nails, pipes and such comes more frequently in inches than mm. A few things are measured in "Arrobas" (Bushels). 
#159




Quote:
But why ? We count in base 10 for intuitive reasons. We have 10 fingers, 10 toes and 10 testicles (what ? You don't ? ). Basing the metric system on that base feels so right, it's actually downright weird that so many traditional unit systems  not just the Imperial system mind you, but also the various currency and weight unit systems used in France circa 1789  eschewed base 10 altogether. I'm sure it all made sense at one point, but I can absolutely grok enlightenment thinkers being born in a world where 1 coin of this equal 240 coins of that each of which are equal to 3 and 4/18th of those going "WHAT THE HELL ?! No. Just no. Let's take it back from the top." (FTR, a couple years ago I had to work on a 9th century document, a market/fair ordinance that ostensibly tried to set up standards for measures, weights and currencies and it was maddening. The fuckers almost had one separate measuring system per crop)
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#160




Quote:
Oddly he US considered the metric system, but before the French revolution it wasn't established enough and they adopted the UK system after being frustrated that the congress selected the troy oz for the mint as it was the only viable option at the time. Last edited by rat avatar; 07172018 at 01:13 PM. 
#161




For most traditional measures there was no such thing as an official conversion factor between miles, chains, rods, furlongs, feet, inches, yards, or whatever, because each traditional measure was used in different contexts, and you'd almost never convert between systems. Along comes the 19th century and various national standards start to emerge, and you get official conversions between incompatible measures, and now for the first time we know how many teaspoons are in a hogshead. But of course that introduces additional problems because the standards set by one body don't match the standards set by another body, and so we have multiple definitions of the ton, we have the mile and the nautical mile, and crazy shit like that.
Hey, metric keeps one traditional unit, the second, which is 1/60th of 1/60th of 1/24th of one day. Nowadays the metric second isn't defined by the day but by the amount of time it takes for a certain number of vibrations of cesium at such and such conditions. If we were starting over from scratch we could have picked round numbers for this rather than some arbitrary number, but it doesn't really matter much because only people building atomic clocks have to know the number, and if they don't have that number written down then maybe they should change careers. 
#162




Quote:
Isn't geography fun! Now with taxes, yay!
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Life ain't peaches and cream, but sometimes it's laughing your ass off when you have no ass.  WhyNot Last edited by Nava; 07172018 at 02:24 PM. 
#163




The answer to the original question of how people were able to convert with relative ease from the British system to the international standard system is that British law defined fixed conversion factors.

#164




And you don't even to memorize the formula. I derive it when needed by converting 100C to 212 F and back. The 32 falls out from freezing point. Trivial.



#165




Quote:
Not just in words like score, dozen and gross, which can sort of be handwaved away as affectations, but in the fact that our base ten counting numbers start with twelve different numbers before going into what is clearly base ten. The etymology is apparently base ten, but different from the rest of the "tens". Danish and French both have clear vigesimal counting numbers, and prior to the 15th century "hundred" in Germanic languages was what came to be known as a long hundred, namely ten dozen. The "weird" measurement systems arose in that world of mixed base counting and adding/subtracting done mostly in your head, not in the modern world where everyone learns multiplication and division with arabic numerals in a solid positional base ten system. 
#166




Quote:
The Sumerians and the Babylonians were base 60 thus our time, angles etc... Base 10 just happened by chance, probably because of the Egyptians, https://en.wikipedia.org/wiki/Rhind_...atical_Papyrus Funny enough, 1,2,6,7,8 and 9 loaves of bread are divided among 10 men and how decimal base was a challenge for them too Last edited by rat avatar; 07172018 at 04:49 PM. 
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