4 ms·

People interested in this should check out Frink. It has been around for a while and has thousands of unit conversions with explanations, as well as a web inter

by j2kun 3y ago

People interested in this should check out Frink. It has been around for a while and has thousands of unit conversions with explanations, as well as a web interface for the unit conversions part https://frinklang.org/ https://frinklang.org/ https://frinklang.org/frinkdata/units.txt https://frinklang.org/frinkdata/units.txt https://frinklang.org/fsp/frink.fsp https://frinklang.org/fsp/frink.fsp

j2kun 3y ago
The units list is hilarious and amazingly detailed, a sample: crocodile := megavolt // used informally in UK physics labs ... footcandle := lumen/ft^2 // Illuminance from a 1 candela source // at a distance of one foot ... // In Britain, the deal is apparently any piece of wood over 6 feet long, over // 7 wide and 2.5 inches thick. The OED doesn't give a standard size. A piece // of wood less than 7 inches wide is called a "batten". This unit is now used // exclusively for fir and pine. deal := 12 ft 11 in 2.5 in // The standard North American deal [OED] wholedeal := 1/2 deal // If it's half as thick as the standard // deal it's called a "whole deal"! splitdeal := 1/2 wholedeal // And half again as thick is a split deal. ... parasang := 3.5 mile // Persian unit of length usually thought // to be between 3 and 3.5 miles
- alok99 3y ago
  The editorial on Hz is particularly funny and insightful. // Beware the SI's broken definition // of Hz. You should treat the radian as being correct, as a fundamental // dimensionless property of the universe that falls out of pure math like // the Taylor series for sin[x], and you should treat the Hz as being a // fundamental property of incompetence by committee. ... // You are perfectly right. You are perfectly wrong. You look dumb and // unreasonable. The person arguing the opposite looks dumb and unreasonable. // // Hz == YOU CANNOT WIN // // (Insert "IT'S A TRAP" image here.)
  - fsh 3y ago
    I don't find this rambling insightful at all. Here is what the BIPM actually says about the topic: The SI unit of frequency is hertz, the SI unit of angular velocity and angular frequency is radian per second, and the SI unit of activity is becquerel, implying counts per second. Although it is formally correct to write all three of these units as the reciprocal second, the use of the different names emphasizes the different nature of the quantities concerned. It is especially important to carefully distinguish frequencies from angular frequencies, because by definition their numerical values differ by a factor1 of 2π. Ignoring this fact may cause an error of 2π. Note that in some countries, frequency values are conventionally expressed using “cycle/s” or “cps” instead of the SI unit Hz, although “cycle” and “cps” are not units in the SI. Note also that it is common, although not recommended, to use the term frequency for quantities expressed in rad/s. Because of this, it is recommended that quantities called “frequency”, “angular frequency”, and “angular velocity” always be given explicit units of Hz or rad/s and not 1/s. I find this very concise and clear.
    - heisenzombie 3y ago
      Right, you can explain it but that doesn’t make it elegant. This is the equivalent of a function with a comment in it saying “Here be dragons!”. One very desirable property of a units system is that incompatible quantities have incompatible units. So if I try to add 1 Joule (== 1 kg⋅m^2⋅s^−2) to 1 meter, I’m obviously doing something wrong and I just can’t continue. But in SI I can take 1 Hertz (==1 s^-1) and add it to 1 radian/second (== 1 s^-1) and SI says sure, that’s 2 s^-1. But it’s not, that’s a totally unphysical thing to do and the answer is nonsense.
      - jonwiseman 3y ago
        That sum to me is both physical and not nonsense, and I think your interpretation is wrong. 1 radian/second != 1 s^-1, but instead ≈ 0.159155 Hz. This is from interpreting a radian as a ratio, in which "doing" one radian in one second is only going over 1/2pi of a whole in a second. So 1 Hz + 1 radian/second, physically and sensibly to me, means ≈ 1.159155 Hz.
op00to 3y ago
I came here to say frink is the master in this space!
krmbzds 3y ago
There is also an open-source Rust implementation called rink-rs. [0] https://github.com/tiffany352/rink-rs/ https://github.com/tiffany352/rink-rs/ [1] https://github.com/tiffany352/rink-rs/blob/master/core/definitions.units https://github.com/tiffany352/rink-rs/blob/master/core/defin... [2] https://rinkcalc.app/ https://rinkcalc.app/
ghaff 3y ago
Years ago, I started a project along those lines and collected a bunch of reference material about a lot of the various units. But, at some point, I had a working program but lost interest in entering all the information that would have needed to have been typed in. (This was long enough ago that there wasn't really an option to cut and paste a lot of it from online.)

by j2kun 3y ago

j2kun 3y ago

The units list is hilarious and amazingly detailed, a sample: crocodile := megavolt // used informally in UK physics labs ... footcandle := lumen/ft^2 // Illuminance from a 1 candela source // at a distance of one foot ... // In Britain, the deal is apparently any piece of wood over 6 feet long, over // 7 wide and 2.5 inches thick. The OED doesn't give a standard size. A piece // of wood less than 7 inches wide is called a "batten". This unit is now used // exclusively for fir and pine. deal := 12 ft 11 in 2.5 in // The standard North American deal [OED] wholedeal := 1/2 deal // If it's half as thick as the standard // deal it's called a "whole deal"! splitdeal := 1/2 wholedeal // And half again as thick is a split deal. ... parasang := 3.5 mile // Persian unit of length usually thought // to be between 3 and 3.5 miles

alok99 3y ago
The editorial on Hz is particularly funny and insightful. // Beware the SI's broken definition // of Hz. You should treat the radian as being correct, as a fundamental // dimensionless property of the universe that falls out of pure math like // the Taylor series for sin[x], and you should treat the Hz as being a // fundamental property of incompetence by committee. ... // You are perfectly right. You are perfectly wrong. You look dumb and // unreasonable. The person arguing the opposite looks dumb and unreasonable. // // Hz == YOU CANNOT WIN // // (Insert "IT'S A TRAP" image here.)
- fsh 3y ago
  I don't find this rambling insightful at all. Here is what the BIPM actually says about the topic: The SI unit of frequency is hertz, the SI unit of angular velocity and angular frequency is radian per second, and the SI unit of activity is becquerel, implying counts per second. Although it is formally correct to write all three of these units as the reciprocal second, the use of the different names emphasizes the different nature of the quantities concerned. It is especially important to carefully distinguish frequencies from angular frequencies, because by definition their numerical values differ by a factor1 of 2π. Ignoring this fact may cause an error of 2π. Note that in some countries, frequency values are conventionally expressed using “cycle/s” or “cps” instead of the SI unit Hz, although “cycle” and “cps” are not units in the SI. Note also that it is common, although not recommended, to use the term frequency for quantities expressed in rad/s. Because of this, it is recommended that quantities called “frequency”, “angular frequency”, and “angular velocity” always be given explicit units of Hz or rad/s and not 1/s. I find this very concise and clear.
  - heisenzombie 3y ago
    Right, you can explain it but that doesn’t make it elegant. This is the equivalent of a function with a comment in it saying “Here be dragons!”. One very desirable property of a units system is that incompatible quantities have incompatible units. So if I try to add 1 Joule (== 1 kg⋅m^2⋅s^−2) to 1 meter, I’m obviously doing something wrong and I just can’t continue. But in SI I can take 1 Hertz (==1 s^-1) and add it to 1 radian/second (== 1 s^-1) and SI says sure, that’s 2 s^-1. But it’s not, that’s a totally unphysical thing to do and the answer is nonsense.
    - jonwiseman 3y ago
      That sum to me is both physical and not nonsense, and I think your interpretation is wrong. 1 radian/second != 1 s^-1, but instead ≈ 0.159155 Hz. This is from interpreting a radian as a ratio, in which "doing" one radian in one second is only going over 1/2pi of a whole in a second. So 1 Hz + 1 radian/second, physically and sensibly to me, means ≈ 1.159155 Hz.

op00to 3y ago

I came here to say frink is the master in this space!

krmbzds 3y ago

There is also an open-source Rust implementation called rink-rs. [0] https://github.com/tiffany352/rink-rs/ https://github.com/tiffany352/rink-rs/ [1] https://github.com/tiffany352/rink-rs/blob/master/core/definitions.units https://github.com/tiffany352/rink-rs/blob/master/core/defin... [2] https://rinkcalc.app/ https://rinkcalc.app/

ghaff 3y ago

Years ago, I started a project along those lines and collected a bunch of reference material about a lot of the various units. But, at some point, I had a working program but lost interest in entering all the information that would have needed to have been typed in. (This was long enough ago that there wasn't really an option to cut and paste a lot of it from online.)