Files
mp-units/example/box_example.cpp
2021-03-16 12:03:25 +01:00

88 lines
2.8 KiB
C++

#include <units/isq/si/constants.h>
#include <units/isq/si/area.h>
#include <units/isq/si/speed.h>
#include <units/isq/si/density.h>
#include <units/isq/si/force.h>
#include <units/isq/si/mass.h>
#include <units/isq/si/time.h>
#include <units/isq/si/volume.h>
#include <units/format.h>
#include <cassert>
#include <iostream>
namespace {
using namespace units::isq;
using m = si::metre;
using m2 = si::square_metre;
using m3 = si::cubic_metre;
using kg = si::kilogram;
using N = si::newton;
using kgpm3 = si::kilogram_per_metre_cub;
inline constexpr auto g = si::si2019::standard_gravity<>;
inline constexpr si::density<kgpm3> air_density(1.225);
class Box {
si::area<m2> base_;
si::length<m> height_;
si::density<kgpm3> density_ = air_density;
public:
constexpr Box(const si::length<m>& length, const si::length<m>& width, si::length<m> height) : base_(length * width), height_(std::move(height)) {}
[[nodiscard]] constexpr si::force<N> filled_weight() const
{
const si::volume<m3> volume = base_ * height_;
const si::mass<kg> mass = density_ * volume;
return mass * g;
}
[[nodiscard]] constexpr si::length<m> fill_level(const si::mass<kg>& measured_mass) const
{
return height_ * measured_mass * g / filled_weight();
}
[[nodiscard]] constexpr si::volume<m3> spare_capacity(const si::mass<kg>& measured_mass) const
{
return (height_ - fill_level(measured_mass)) * base_;
}
constexpr void set_contents_density(const si::density<kgpm3>& density_in)
{
assert(density_in > air_density);
density_ = density_in;
}
};
} // namespace
int main()
{
using namespace units;
using namespace si::literals;
const si::length<m> height(200.0_q_mm);
auto box = Box(1000.0_q_mm, 500.0_q_mm, height);
box.set_contents_density(1000.0_q_kg_per_m3);
const auto fill_time = 200.0_q_s; // time since starting fill
const auto measured_mass = 20.0_q_kg; // measured mass at fill_time
const Length auto fill_level = box.fill_level(measured_mass);
const Dimensionless auto fill_percent = quantity_cast<percent>(fill_level / height);
const Volume auto spare_capacity = box.spare_capacity(measured_mass);
const auto input_flow_rate = measured_mass / fill_time; // unknown dimension
const Speed auto float_rise_rate = fill_level / fill_time;
const Time auto fill_time_left = (height / fill_level - 1) * fill_time;
std::cout << "mp-units box example...\n";
std::cout << fmt::format("fill height at {} = {} ({} full)\n", fill_time, fill_level, fill_percent);
std::cout << fmt::format("spare_capacity at {} = {}\n", fill_time, spare_capacity);
std::cout << fmt::format("input flow rate after {} = {}\n", fill_time, input_flow_rate);
std::cout << fmt::format("float rise rate = {}\n", float_rise_rate);
std::cout << fmt::format("box full E.T.A. at current flow rate = {}\n", fill_time_left);
}