forked from mpusz/mp-units
49 lines
1.8 KiB
ReStructuredText
49 lines
1.8 KiB
ReStructuredText
.. namespace:: units
|
|
|
|
International System of Quantities (ISQ)
|
|
========================================
|
|
|
|
According to [ISO80000]_:
|
|
|
|
The system of quantities, including the relations among them the quantities used as the basis of the units of
|
|
the SI, is named the **International System of Quantities**, denoted "ISQ", in all languages.
|
|
|
|
|
|
Base dimensions and their symbols
|
|
---------------------------------
|
|
|
|
According to the [SIBrochure]_:
|
|
|
|
Physical quantities can be organized in a system of dimensions, where the system used is
|
|
decided by convention. Each of the seven base quantities used in the SI is regarded as
|
|
having its own dimension. The symbols used for the base quantities and the symbols used
|
|
to denote their dimension are shown in Table 3.
|
|
|
|
Following that the library provides the following definitions::
|
|
|
|
namespace units::isq {
|
|
|
|
template<Unit U> struct dim_time : base_dimension<"T", U> {};
|
|
template<Unit U> struct dim_length : base_dimension<"L", U> {};
|
|
template<Unit U> struct dim_mass : base_dimension<"M", U> {};
|
|
template<Unit U> struct dim_electric_current : base_dimension<"I", U> {};
|
|
template<Unit U> struct dim_thermodynamic_temperature : base_dimension<"Θ", U> {};
|
|
template<Unit U> struct dim_amount_of_substance : base_dimension<"N", U> {};
|
|
template<Unit U> struct dim_luminous_intensity : base_dimension<"J", U> {};
|
|
|
|
}
|
|
|
|
Base dimension symbols provided above are consistently defined by both [SIBrochure]_ and [ISO80000]_.
|
|
|
|
|
|
Derived dimensions
|
|
------------------
|
|
|
|
[SIBrochure]_ states:
|
|
|
|
Since the number of quantities is without limit, it is not possible to
|
|
provide a complete list of derived quantities and derived units.
|
|
|
|
The authors of this library decided to limit the set of defined quantities to all
|
|
quantities defined in the [ISO80000]_ series of documents.
|