From 45888ac44e9fdeda18321fc4a61b77699cb05e18 Mon Sep 17 00:00:00 2001
From: Mateusz Pusz <mateusz.pusz@gmail.com>
Date: Tue, 17 Mar 2020 17:13:18 +0100
Subject: [PATCH] Physical constants support redesigned

---
 example/box_example.cpp                       |  2 +-
 example/total_energy.cpp                      |  8 ++--
 .../units/physical/natural/constants.h        |  3 +-
 src/include/units/physical/si/constants.h     | 40 ++++++++++++++-----
 4 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/example/box_example.cpp b/example/box_example.cpp
index 17f59401..1bc7a5ba 100644
--- a/example/box_example.cpp
+++ b/example/box_example.cpp
@@ -20,7 +20,7 @@ using N = si::newton;
 using m3 = si::cubic_metre;
 using kgpm3 = si::kilogram_per_metre_cub;
 
-inline constexpr auto g = si::standard_gravity;
+inline constexpr auto g = si::si2019::standard_gravity<>;
 
 }  // namespace
 
diff --git a/example/total_energy.cpp b/example/total_energy.cpp
index f4120879..79d59e52 100644
--- a/example/total_energy.cpp
+++ b/example/total_energy.cpp
@@ -42,12 +42,12 @@ void si_example()
   using namespace si;
   using GeV = gigaelectronvolt;
 
-  constexpr Velocity AUTO c = speed_of_light;
+  constexpr Velocity AUTO c = si2019::speed_of_light<>;
 
   std::cout << "\n*** SI units (c = " << c << ") ***\n";
 
-  const Momentum AUTO p = 4.q_GeV / speed_of_light;
-  const Mass AUTO m = 3.q_GeV / pow<2>(speed_of_light);
+  const Momentum AUTO p = 4.q_GeV / c;
+  const Mass AUTO m = 3.q_GeV / pow<2>(c);
   const Energy AUTO E = total_energy(p, m, c);
 
   std::cout << "[in GeV]\n"
@@ -73,7 +73,7 @@ void natural_example()
   using namespace natural;
   using GeV = gigaelectronvolt;
 
-  constexpr Velocity AUTO c = speed_of_light;
+  constexpr Velocity AUTO c = speed_of_light<>;
   const momentum<GeV> p(4);
   const mass<GeV> m(3);
   const Energy AUTO E = total_energy(p, m, c);
diff --git a/src/include/units/physical/natural/constants.h b/src/include/units/physical/natural/constants.h
index 4de79f28..e8350da8 100644
--- a/src/include/units/physical/natural/constants.h
+++ b/src/include/units/physical/natural/constants.h
@@ -26,6 +26,7 @@
 
 namespace units::natural {
 
-inline constexpr auto speed_of_light = velocity<unitless>(1);
+template<Scalar Rep = double>
+inline constexpr auto speed_of_light = velocity<unitless, Rep>(1);
 
 }  // namespace units::natural
diff --git a/src/include/units/physical/si/constants.h b/src/include/units/physical/si/constants.h
index 7135aad1..ed19febd 100644
--- a/src/include/units/physical/si/constants.h
+++ b/src/include/units/physical/si/constants.h
@@ -23,24 +23,44 @@
 #pragma once
 
 #include <units/physical/si/electric_charge.h>
-#include <units/physical/si/frequency.h>
 #include <units/physical/si/energy.h>
+#include <units/physical/si/frequency.h>
 #include <units/physical/si/power.h>
 #include <units/physical/si/substance.h>
-#include <units/physical/si/velocity.h>
 #include <units/physical/si/temperature.h>
+#include <units/physical/si/velocity.h>
 
 namespace units::si {
 
-inline constexpr auto planck_constant = 6.62607015e-34q_J * 1q_s;
-inline constexpr auto reduced_planck_constant = 6.582119569e-10q_GeV * 1q_s;
-inline constexpr auto elementary_charge = 1.602176634e-19q_C;
-inline constexpr auto boltzmann_constant = 1.380649e-23q_J / 1q_K;
-inline constexpr auto avogadro_constant = 6.02214076e23 / 1q_mol;
-inline constexpr auto speed_of_light = 299792458q_m_per_s;
-inline constexpr auto hyperfine_structure_transition_frequency = 9192631770q_Hz;
+namespace si2019 {
+
+template<Scalar Rep = double>
+inline constexpr auto planck_constant = energy<joule, Rep>(6.62607015e-34) * time<second, Rep>(1);
+
+template<Scalar Rep = double>
+inline constexpr auto reduced_planck_constant = energy<gigaelectronvolt, Rep>(6.582119569e-10) * time<second, Rep>(1);
+
+template<Scalar Rep = double>
+inline constexpr auto elementary_charge = electric_charge<coulomb, Rep>(1.602176634e-19);
+
+template<Scalar Rep = double>
+inline constexpr auto boltzmann_constant = energy<joule, Rep>(1.380649e-23) / temperature<kelvin, Rep>(1);
+
+template<Scalar Rep = double>
+inline constexpr auto avogadro_constant = Rep(6.02214076e23) / substance<mole, Rep>(1);
+
+template<Scalar Rep = double>
+inline constexpr auto speed_of_light = velocity<metre_per_second, Rep>(299792458);
+
+template<Scalar Rep = double>
+inline constexpr auto hyperfine_structure_transition_frequency = frequency<hertz, Rep>(9192631770);
+
+// template<Scalar Rep = double>
 // inline constexpr auto luminous_efficacy = 683q_lm / 1q_W;
 
-inline constexpr auto standard_gravity = 9.80665q_m_per_s2;
+template<Scalar Rep = double>
+inline constexpr auto standard_gravity = acceleration<metre_per_second_sq, Rep>(9.80665);
+
+}  // namespace si2019
 
 }  // namespace units::si