Comments (4)
A link to examples
in the top level folder would be very helpful, as would additional explanation of what the macros actually do.
from uom.
If anyone else is confused about how to use it, or if you base as an example on this, this is what I did for now. (I noticed I need a smaller length resolution, not a smaller time resolution, to get a better speed resolution, duh, so it's decimillimeters, not decimilliseconds as in my previous post.)
#[macro_use]
extern crate uom;
// With a target location resolution in centimeters, the underlying model
// should use millimeters to avoid too many rounding artefacts. For speeds
// up to 300 km/h at that space resolution, we would need time resolutions
// of 10^-3 seconds.
//
// Now, working in millimeters and i32 already gives us a maximum length of
// 2147 km, which should be sufficient for any track within Germany. Any
// bigger data type will also be sufficient.
//
// For 10^-3 seconds, i32 can represent about 25 days, which is just about
// sufficient most use cases of our simulation. Larger time frames will have to
// use offsets external to the simulation, and have to be persisted, adapted to
// the new offset, and re-started.
//
// However, with millimeters and milliseconds, the base unit of velocity is
// mm/ms = m/s, which is less than resolution of km/h = 0.278 m/s we would like
// to be able to talk about. So we reduce the space resolution once again, to
// 10^-4 meters.
mod trainphysics_units {
#[macro_use]
mod length {
quantity! {
/// Length (base unit meter, m).
quantity: Length; "length";
/// Length dimension, m
dimension: LMT<P1, Z0, Z0>;
units {
@decimillimeter: 0.0001; "dmm", "decimillimeter", "decimillimeters";
@millimeter: 0.001; "mm", "millimeter", "millimeters";
@centimeter: 0.01; "cm", "centimeter", "centimeters";
@meter: 1.; "m", "meter", "meters";
@kilometer: 1000.; "km", "kilometer", "kilometers";
}
}
}
#[macro_use]
mod mass {
quantity! {
/// Mass (base unit kilogram, kg).
quantity: Mass; "mass";
/// Mass dimension, kg
dimension: LMT<Z0, P1, Z0>;
units {
@kilogram: 1.; "kg", "kilogram", "kilograms";
@ton: 1000.; "T", "ton", "tons";
}
}
}
#[macro_use]
mod time {
quantity! {
/// Time (base unit second, s).
quantity: Time; "time";
/// Time dimension, s
dimension: LMT<Z0, Z0, P1>;
units {
@millisecond: 0.001; "ms", "millisecond", "milliseconds";
@second: 1.; "s", "second", "seconds";
@minute: 60.; "min", "minute", "minutes";
@hour: 3600.; "h", "hour", "hours";
@day: 86400.; "d", "day", "days";
}
}
}
#[macro_use]
mod velocity {
quantity! {
/// Velocity (base unit meters per second, m/s).
quantity: Velocity; "velocity";
/// Velocity dimension, m/s
dimension: LMT<P1, Z0, N1>;
units {
@meter_per_second: 1.; "m/s", "meter per second", "meters per second";
@kilometer_per_hour: 2.777_777_777_777_778_E-1; "km/h", "kilometer per hour", "kilometers per hour";
}
}
}
#[macro_use]
mod acceleration {
quantity! {
/// Acceleration (base unit meters per second squared, m/s²).
quantity: Acceleration; "acceleration";
/// Acceleration dimension, m/s²
dimension: LMT<P1, Z0, N2>;
units {
@meter_per_second_squared: 1.; "m/s²", "meter per second squared", "meters per second squared";
}
}
}
#[macro_use]
mod power {
quantity! {
/// Power (base unit Watt).
quantity: Power; "power";
/// Power dimension, m²kg/s³
dimension: LMT<P2, P1, N3>;
units {
@watt: 1.; "W", "watt", "watts";
}
}
}
system! {
/// System of quantities, Q.
quantities: LMT {
length: meter, L;
mass: kilogram, M;
time: second, T;
}
/// System of units, U.
units: U {
mod length::Length,
mod mass::Mass,
mod time::Time,
mod velocity::Velocity,
mod acceleration::Acceleration,
mod power::Power,
}
}
pub mod i32 {
LMT!(
crate::trainphysics_units,
i32,
(decimillimeter, kilogram, millisecond)
);
}
}
use trainphysics_units::i32::{Acceleration, Length, Mass, Time, Velocity, Power};
from uom.
@Anaphory Did you end up resolving all your issues or did you still have some questions?
Setting up new type aliases with different base units is definitely not intuitive and probably not easy to discover. Any concrete suggestions, especially about documentation, based on your experience?
For anyone coming to this issue in the future, examples/base.rs, gives a minimal example of setting up type aliases with different base units. The ISQ! macro is also documented.
from uom.
Bumping this thread. I for one would like a clearer example of defining custom unit systems with nonstandard base units such as mm or ms to avoid the use of floating point numbers.
Thanks in advance
from uom.
Related Issues (20)
- Unable to `clamp` quantity to a range. HOT 2
- Unexpected inequality with large conversion factor HOT 6
- Allow subtracting two thermodynamic temperatures HOT 3
- Deserialize references to quantities HOT 2
- New unit `ElectricalSusceptance` HOT 1
- Change of base_unit of Ratio quantity HOT 1
- Conversion to/from complex storage types is wrong
- Quantity-Aware access parts of quantity with complex storage type HOT 2
- Consider rust-specific cache action HOT 1
- Built-In SI system has no alias for Angular Momentum
- Unit conversion problem using BigRational
- Unclear about how to create arbitrary quantities with arbitrary units HOT 6
- Conversion to Watts HOT 1
- Newbie Feedback HOT 1
- New release HOT 1
- NIST Special Publication link
- Add a feature for bytemuck and/or zerocopy to `Quantity`
- Support fixed-point storage type(s)
- Better precision and abbreviation change for `astronomical_unit` HOT 6
- Implement clamp for f64 Quantities
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from uom.