Files
mp-units/example/box_example.cpp
2020-01-14 12:50:30 +01:00

119 lines
3.1 KiB
C++

#include <units/physical/si/acceleration.h>
#include <units/physical/si/density.h>
#include <units/physical/si/force.h>
#include <units/physical/si/length.h>
#include <units/physical/si/mass.h>
#include <units/physical/si/time.h>
#include <units/physical/si/volume.h>
#include <cassert>
namespace {
namespace length {
template<typename Rep = double>
using m = units::si::length<units::si::metre, Rep>;
template<typename Rep = double>
using mm = units::si::length<units::si::millimetre, Rep>;
} // namespace length
namespace acceleration {
template<typename Rep = double>
using mps2 = units::si::acceleration<units::si::metre_per_second_sq, Rep>;
template<typename Rep = double>
constexpr mps2<> g{static_cast<Rep>(9.80665)};
} // namespace acceleration
namespace force {
template<typename Rep = double>
using N = units::si::force<units::si::newton, Rep>;
}
namespace mass {
template<typename Rep = double>
using kg = units::si::mass<units::si::kilogram, Rep>;
}
namespace density {
template<typename Rep = double>
using kgpm3 = units::si::density<units::si::kilogram_per_metre_cub, Rep>;
}
namespace volume {
template<typename Rep = double>
using m3 = units::si::volume<units::si::cubic_metre, Rep>;
}
} // namespace
struct Box {
static constexpr density::kgpm3<> air_density{1.225};
length::m<> length;
length::m<> width;
length::m<> height;
struct contents {
density::kgpm3<> density = air_density;
} contents;
Box(const length::m<>& l, const length::m<>& w, const length::m<>& h) : length{l}, width{w}, height{h} {}
force::N<> filled_weight() const
{
const volume::m3<> volume = length * width * height;
const mass::kg<> mass = contents.density * volume;
return mass * acceleration::g<>;
}
length::m<> fill_level(const mass::kg<>& measured_mass) const
{
return height * (measured_mass * acceleration::g<>) / filled_weight();
}
volume::m3<> spare_capacity(const mass::kg<>& measured_mass) const
{
return (height - fill_level(measured_mass)) * width * length;
}
void set_contents_density(const density::kgpm3<>& density_in)
{
assert(density_in > air_density);
contents.density = density_in;
}
};
#include <iostream>
using namespace units::si::literals;
int main()
{
auto box = Box{1000.0mm, 500.0mm, 200.0mm};
box.set_contents_density(1000.0kgpm3);
auto fill_time = 200.0s; // time since starting fill
auto measured_mass = 20.0kg; // measured mass at fill_time
std::cout << "mpusz/units box example...\n";
std::cout << "fill height at " << fill_time << " = " << box.fill_level(measured_mass) << " ("
<< (box.fill_level(measured_mass) / box.height) * 100 << "% full)\n";
std::cout << "spare_capacity at " << fill_time << " = " << box.spare_capacity(measured_mass) << '\n';
std::cout << "input flow rate after " << fill_time << " = " << measured_mass / fill_time << '\n';
std::cout << "float rise rate = " << box.fill_level(measured_mass) / fill_time << '\n';
auto fill_time_left = (box.height / box.fill_level(measured_mass) - 1) * fill_time;
std::cout << "box full E.T.A. at current flow rate = " << fill_time_left << '\n';
}