xo-unit: + scaled_unit.is_natural()

docs/implementation.rst

@@ -0,0 +1,191 @@
+.. _abstractions:
+
+Representation
+==============
+
+.. ditaa::
+
+    +-----------+-----------+
+    |  quantity | xquantity |
+    +-----------+-----------+
+    |      scaled_unit      |
+    +-----------------------+
+    |     natural_unit      |
+    +-----------------------+
+    |          bpu          |
+    +-----------------------+
+    |       basis_unit      |
+    +-----------------------+
+    |       dimension       |
+    +-----------------------+
+
+- quantity: see :doc:`quantity-reference`
+
+.. code-block:: cpp
+    :linenos:
+    :emphasize-lines: 6
+
+    #include "xo/unit/quantity.hpp"
+    ...
+    namespace q = xo::qty::qty;
+
+    // 7.55km.min^-2
+    quantity qty1 = 7.55 * q::kilometer / (q::minute * q::minute);
+
+.. uml::
+    :caption: representation for quantity 7.55km.min^-2
+    :scale: 99%
+    :align: center
+
+    object qty1<<quantity>>
+    qty1 : scale = 7.55
+
+    rectangle {
+
+    object km_per_min2<<natural_unit>>
+    km_per_min2 : n_bpu = 2
+    km_per_min2 : bpu[0] = km
+    km_per_min2 : bpu[1] = per_min
+
+    object km<<bpu>>
+    km : native_dim = dim.mass
+    km : scalefactor = 1000/1
+    km : power = 1
+
+    object per_min2<<bpu>>
+    per_min2 : native_dim = dim.time
+    per_min2 : scalefactor = 60/1
+    per_min2 : power = -2
+
+    qty1 o-- km_per_min2 : s_unit (static constexpr)
+
+    km_per_min2 *-- km
+    km_per_min2 *-- per_min2
+
+    }
+
+.. code-block:: cpp
+   :linenos:
+
+   // 123ng
+   quantity qty2 = q::nanograms(123);
+
+.. uml::
+    :caption: representation for quantity 123 nanograms
+    :scale: 99%
+    :align: center
+
+    object qty2<<quantity>>
+    qty2 : scale = 123
+
+    rectangle {
+
+    object ng_unit<<natural_unit>>
+    ng_unit : n_bpu = 1
+    ng_unit : bpu[0] = ng
+
+    object ng<<bpu>>
+    ng : native_dim = dim::mass
+    ng : scalefactor = 1/10^9
+    ng : power = 1
+
+    qty2 o-- ng_unit : s_unit (static constexpr)
+
+    ng_unit *-- ng
+
+    }
+
+.. code-block:: cpp
+    :linenos:
+
+    // (123*7.55) ng.km.min^-2
+    quantity qty3 = qty2 * qty1;
+
+.. uml::
+    :caption: quantity 928.65 ng.km.min^-2
+    :scale: 99%
+    :align: center
+
+    object qty3<<quantity>>
+    qty3 : scale = 928.65
+
+    rectangle {
+
+      object ng_km_min2_unit<<natural_unit>>
+      ng_km_min2_unit : n_bpu = 3
+      ng_km_min2_unit : bpu[0] = ng
+      ng_km_min2_unit : bpu[1] = km
+      ng_km_min2_unit : bpu[2] = per_min2
+
+      object ng<<bpu>>
+      ng : native_dim = dim::mass
+      ng : scalefactor = 1/10^9
+      ng : power = 1
+
+      object km<<bpu>>
+      km : native_dim = dim::distance
+      km : scalefactor = 1000/1
+      km : power = 1
+
+      object per_min2<<bpu>>
+      per_min2 : native_dim = dim::time
+      per_min2 : scalefactor = 60/1
+      per_min2 : power = -2
+
+      qty3 o-- ng_km_min2_unit : s_unit (static constexpr)
+
+      ng_km_min2_unit *-- ng
+      ng_km_min2_unit *-- km
+      ng_km_min2_unit *-- per_min2
+    }
+
+.. code-block:: cpp
+    :linenos:
+
+    namespace su = xo::qty::su;
+
+    // (123*7.55) ng.km.min^-2  ==>  2.57958e-10kg.m.s^-2
+
+    quantity qty3b = qty3.rescale_ext<su::kilogram * su::meter / (su::second * su::second)>();
+
+.. uml::
+    :caption: quantity 928.65 ng.km.min^-2
+    :scale: 99%
+    :align: center
+
+    object qty3b<<quantity>>
+    qty3b : scale = 2.59758e-10
+
+    rectangle {
+
+      object kg_m_s2_unit<<natural_unit>>
+      kg_m_s2_unit : n_bpu = 3
+      kg_m_s2_unit : bpu[0] = kg
+      kg_m_s2_unit : bpu[1] = m
+      kg_m_s2_unit : bpu[2] = per_s2
+
+      object kg<<bpu>>
+      kg : native_dim = dim::mass
+      kg : scalefactor = 1000/1
+      kg : power = 1
+
+      object m<<bpu>>
+      m : native_dim = dim::distance
+      m : scalefactor = 1/1
+      m : power = 1
+
+      object per_s2<<bpu>>
+      per_s2 : native_dim = dim::time
+      per_s2 : scalefactor = 1/1
+      per_s2 : power = -2
+
+      qty3b o-- kg_m_s2_unit : s_unit (static constexpr)
+
+      kg_m_s2_unit *-- kg
+      kg_m_s2_unit *-- m
+      kg_m_s2_unit *-- per_s2
+    }
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Abstractions