Loci

#include <Loci.h>
using namespace Loci;

// Declare variable types for compressible flow simulation
$type pressure    store<double>;  // cell pressure [Pa]
$type density     store<double>;  // cell density [kg/m^3]
$type temperature store<double>;  // cell temperature [K]
$type soundSpeed  store<double>;  // local speed of sound [m/s]
$type gamma       param<double>;  // ratio of specific heats
$type gasConstant param<double>;  // specific gas constant [J/kg/K]

// Default physical constants (dry air)
$rule default(gamma) {
  $gamma = 1.4;
}

$rule default(gasConstant) {
  $gasConstant = 287.058;  // J/kg/K
}

// Ideal gas law: p = rho * R * T
$rule pointwise(pressure <- density, temperature, gasConstant) {
  $pressure = $density * $gasConstant * $temperature;
}

// Speed of sound: c = sqrt(gamma * p / rho)
$rule pointwise(soundSpeed <- gamma, pressure, density) {
  $soundSpeed = sqrt($gamma * $pressure / $density);
}