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This example demonstrates how to use quantities of our toy unit system :
quantity<length> L = 2.0*meters; // quantity of length quantity<energy> E = kilograms*pow<2>(L/seconds); // quantity of energy
giving us the basic quantity functionality :
L = 2 m L+L = 4 m L-L = 0 m L*L = 4 m^2 L/L = 1 dimensionless L*meter = 2 m^2 kilograms*(L/seconds)*(L/seconds) = 4 m^2 kg s^-2 kilograms*(L/seconds)^2 = 4 m^2 kg s^-2 L^3 = 8 m^3 L^(3/2) = 2.82843 m^(3/2) 2vL = 1.41421 m^(1/2) (3/2)vL = 1.5874 m^(2/3)
As a further demonstration of the flexibility of the system, we replace the
double
value type with a std::complex<double>
value type (ignoring the question of
the meaningfulness of complex lengths and energies) :
quantity<length,std::complex<double> > L(std::complex<double>(3.0,4.0)*meters); quantity<energy,std::complex<double> > E(kilograms*pow<2>(L/seconds));
and find that the code functions exactly as expected with no additional work,
delegating operations to std::complex<double>
and performing the appropriate dimensional
analysis :
L = (3,4) m L+L = (6,8) m L-L = (0,0) m L*L = (-7,24) m^2 L/L = (1,0) dimensionless L*meter = (3,4) m^2 kilograms*(L/seconds)*(L/seconds) = (-7,24) m^2 kg s^-2 kilograms*(L/seconds)^2 = (-7,24) m^2 kg s^-2 L^3 = (-117,44) m^3 L^(3/2) = (2,11) m^(3/2) 2vL = (2,1) m^(1/2) (3/2)vL = (2.38285,1.69466) m^(2/3)