https://github.com/doganulus/scalr
std::chrono inspired physical quantity/unit representation and manipulation library for C++11/14/17
https://github.com/doganulus/scalr
cpp11 dimensional-analysis physical-units quantity units
Last synced: 6 months ago
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std::chrono inspired physical quantity/unit representation and manipulation library for C++11/14/17
- Host: GitHub
- URL: https://github.com/doganulus/scalr
- Owner: doganulus
- License: mpl-2.0
- Created: 2020-05-22T13:19:49.000Z (over 5 years ago)
- Default Branch: main
- Last Pushed: 2023-11-29T12:59:40.000Z (almost 2 years ago)
- Last Synced: 2024-05-02T01:07:22.566Z (over 1 year ago)
- Topics: cpp11, dimensional-analysis, physical-units, quantity, units
- Language: C++
- Homepage:
- Size: 695 KB
- Stars: 2
- Watchers: 2
- Forks: 1
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Scalr
Scalr is a `std::chrono` inspired C++ library for the representation and manipulation of scalar physical quantities and their units of measurements.
Scalr is a work in progress...
## Features and goals
* C++11/14/17 compatibility
* Compile-time dimension analysis
* User experience of popular `std::chrono` library
* Shorter and more meaningful compilation errors --> good to have
* User-defined literals for units and std::cout support --> good to have
## Quick look
Scalr is based on the International System (SI) of Units starting with seven base dimensions. In the nutshell, Scalr provides a generic compile-time dimension/unit arithmetic as well as defines a facade for named quantities with `std::chrono::duration` style. Using Scalr, we define physical quantities as follows:
```c++
scalr::duration> secs(120);
scalr::speed> kphs(18.0);
scalr::length> dist(0.6);
CHECK(dist == (kph * secs)); // Pass
```
However, the compiler would complain if you make a dimensional mistake such as:
```c++
static_assert(kms == (kph * secs)); // Fail
```
Such compile-time guarantees and automatic (lazy) conversions between units are the reason why you should use Scalr.
Moreover, a number of helper aliases is available for named units. For example,
```c++
using hours = duration>;
using minutes = duration>;
using seconds = duration;
using meters_per_second = speed>;
using kilometers_per_hour = speed>;
using miles_per_hour = speed>;
using kilohertz = frequency;
using grams = mass>;
```
The source directory of named quantities and unit can be found [here](https://github.com/doganulus/scalr/tree/master/include/scalr/named_quantity) for the reference.
Finally the [design document](https://github.com/doganulus/scalr/tree/master/docs/design.md) gives more information about the underlying structures and how it works.
## Other Libraries
There are quite a number of similar libraries in existence. Some prominent ones are listed below, with my short comments.
* [boost/units](https://www.boost.org/doc/libs/1_51_0/doc/html/boost_units.html) - Heavy design. I think `std::chrono` does a better job to handle time quantities.
* [mputsz/units](https://github.com/mpusz/units) - New proposal for the future C++23 standard, not compatible with C++11/14/17. Besides I am not in favor of explicit systems as in Boost.
* [PhysUnits-CT-Cpp11](https://github.com/martinmoene/PhysUnits-CT-Cpp11) - Close to Scalr in many ways but eagerly converts quantities to base units (unlike the lazy way in std::chrono::duration implementations, which has certain advantages).
* [nholthaus/units](https://github.com/nholthaus/units) - Has some very nice features but not compatible with C++11. Besides representation type cannot be selected independently.