Velocity renamed to Speed (resolves #103)

docs/framework/constants.rst

@@ -19,7 +19,7 @@ For example the speed of light constant in :term:`SI` is defined as::
     namespace si::si2019 {
 
     template<Scalar Rep = double>
-    inline constexpr auto speed_of_light = velocity<metre_per_second, Rep>(299792458);
+    inline constexpr auto speed_of_light = speed<metre_per_second, Rep>(299792458);
 
     }
 
@@ -28,6 +28,6 @@ The same constant defined for natural units may be provided as::
     namespace natural {
 
     template<Scalar Rep = double>
-    inline constexpr auto speed_of_light = velocity<unitless, Rep>(1);
+    inline constexpr auto speed_of_light = speed<unitless, Rep>(1);
 
     }

docs/framework/dimensions.rst

@@ -5,7 +5,7 @@ Dimensions
 
 In the previous chapter we briefly introduced the notion of a physical
 :term:`dimension`. Now it is time to learn much more about this subject.
-Length, time, velocity, area, energy are only a few examples of physical
+Length, time, speed, area, energy are only a few examples of physical
 dimensions.
 
 Operations
@@ -45,7 +45,7 @@ probably will always end up in a quantity of a yet another dimension:
     Length auto dist2 = 3q_m;
     Time auto dur1 = 2q_s;
     Area auto res1 = dist1 * dist2;     // 6 m²
-    Velocity auto res2 = dist1 / dur1;  // 1 m/s
+    Speed auto res2 = dist1 / dur1;     // 1 m/s
     Frequency auto res3 = 10 / dur1;    // 5 Hz
 
 However, please note that there is an exception from the above rule.
@@ -96,12 +96,12 @@ The quantities of derived dimensions are called
 quantities. This means that they are created by multiplying or dividing
 quantities of other dimensions.
 
-Looking at the previous code snippets the area, velocity, or frequency are
+Looking at the previous code snippets the area, speed, or frequency are
 the examples of such quantities. Each derived quantity can be represented
 as a unique list of exponents of base quantities. For example:
 
 - an area is a length base quantity raised to the exponent ``2``
-- a velocity is formed from the length base quantity with exponent ``1``
+- a speed is formed from the length base quantity with exponent ``1``
   and time base quantity with exponent ``-1``.
 
 The above dimensions can be defined in the library with the

docs/framework/quantities.rst

@@ -82,14 +82,14 @@ quantities. The usage of such a function can look as follows::
 
     using namespace units::physical::si::literals;
     using namespace units::physical::international::literals;
-    constexpr Velocity auto v1 = avg_speed(220q_km, 2q_h);
-    constexpr Velocity auto v2 = avg_speed(140q_mi, 2q_h);
+    constexpr Speed auto v1 = avg_speed(220q_km, 2q_h);
+    constexpr Speed auto v2 = avg_speed(140q_mi, 2q_h);
 
 In this and all other physical units libraries such a function can be
 implemented as::
 
-    constexpr si::velocity<si::metre_per_second> avg_speed(si::length<si::metre> d,
-                                                           si::time<si::second> t)
+    constexpr si::speed<si::metre_per_second> avg_speed(si::length<si::metre> d,
+                                                        si::time<si::second> t)
     {
       return d / t;
     }
@@ -114,7 +114,7 @@ are returning a physical quantity of a correct dimension. For this
 dimension-specific concepts come handy again and with usage of C++20 generic
 functions our function can look as simple as::
 
-    constexpr Velocity auto avg_speed(Length auto d, Time auto t)
+    constexpr Speed auto avg_speed(Length auto d, Time auto t)
     {
       return d / t;
     }
@@ -141,7 +141,7 @@ but often we would like to know a specific type too. We have two options here:
 
 - query the actual dimension, unit, and representation types::
 
-    constexpr Velocity auto v = avg_speed(220q_km, 2q_h);
+    constexpr Speed auto v = avg_speed(220q_km, 2q_h);
     using quantity_type = decltype(v);
     using dimension_type = quantity_type::dimension;
     using unit_type = quantity_type::unit;
@@ -149,9 +149,9 @@ but often we would like to know a specific type too. We have two options here:
 
 - convert or cast to a desired quantity type::
 
-    constexpr Velocity auto v1 = avg_speed(220.q_km, 2q_h);
-    constexpr si::velocity<si::metre_per_second> v2 = v1;
-    constexpr Velocity auto v3 = quantity_cast<si::velocity<si::metre_per_second>(v1);
+    constexpr Speed auto v1 = avg_speed(220.q_km, 2q_h);
+    constexpr si::speed<si::metre_per_second> v2 = v1;
+    constexpr Speed auto v3 = quantity_cast<si::speed<si::metre_per_second>(v1);
 
 .. seealso::
 

docs/framework/text_output.rst

@@ -14,8 +14,8 @@ stream::
 
     using namespace units::physical::si::literals;
     using namespace units::physical::international::literals;
-    constexpr Velocity auto v1 = avg_speed(220.q_km, 2q_h);
-    constexpr Velocity auto v2 = avg_speed(140.q_mi, 2q_h);
+    constexpr Speed auto v1 = avg_speed(220.q_km, 2q_h);
+    constexpr Speed auto v2 = avg_speed(140.q_mi, 2q_h);
     std::cout << v1 << '\n';  // 110 km/h
     std::cout << v2 << '\n';  // 70 mi/h
 

docs/framework/units.rst

@@ -137,7 +137,7 @@ where ``kilogram_metre_per_second`` is defined as::
     struct kilogram_metre_per_second : unit<kilogram_metre_per_second> {};
 
 However, the easiest way to define momentum is just to use the
-`si::velocity` derived dimension in the recipe:
+`si::speed` derived dimension in the recipe:
 
 .. code-block::
     :emphasize-lines: 3