constants.hpp

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/*
 * BELFEM -- The Berkeley Lab Finite Element Framework
 * Copyright (c) 2026, The Regents of the University of California,
 * through Lawrence Berkeley National Laboratory (subject to receipt of any required
 * approvals from the U.S. Dept. of Energy).  All rights reserved.
 *
 * Developers: Christian Messe, Gregory Giard
 *
 * See the top-level LICENSE file for the complete license and disclaimer.
 */
 
 
#ifndef BELFEM_CONSTANTS_HPP
#define BELFEM_CONSTANTS_HPP
#include <cmath>
#include "typedefs.hpp"
 
#if defined(__clang__)
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-variable"
 
#elif defined(__GNUC__) || defined(__GNUG__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-variable"
#endif
 
#define BELFEM_TREF 298.15
#define BELFEM_PREF 100000.0
 
namespace belfem
{
    namespace constant
    {
//------------------------------------------------------------------------------
// MATH
//------------------------------------------------------------------------------

        const real pi = 3.141592653589793238462643383279502884;
 
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        const real phi = 0.5 * ( 1.0 + std::sqrt( 5.0 ) );
 
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        const real deg = pi / 180.0;
 
//------------------------------------------------------------------------------
// GENERAL PHYSICS
//------------------------------------------------------------------------------

        const real c = 299792458.0 ;
 
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        const real mu0 = 1.25663706212e-6;
 
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        const real nu0 = 1./mu0 ;
 
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        const real epsilon0 = 1.0/( mu0*std::pow( c, 2 ) );
 
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        const real G = 6.67430e-11;
 
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

        const real e = 1.602176634e-19 ;
 
 
//------------------------------------------------------------------------------
// THERMODYNAMICS
//------------------------------------------------------------------------------

        const real calTh = 4.184;
 
//------------------------------------------------------------------------------

        const real kB = 1.380649e-23;
 
 
//------------------------------------------------------------------------------

         const real NA = 6.02214076e23;
 
//------------------------------------------------------------------------------

        const real u = 0.001 / NA ;
 
//------------------------------------------------------------------------------

        const real Rm = kB * NA; // 8.3144598;
 
//------------------------------------------------------------------------------

        const real Rm_cal = Rm / calTh;
 
//------------------------------------------------------------------------------

         const real h = 6.62607015e-34;
 
//------------------------------------------------------------------------------

         const real sigma = 2.0 * std::pow( pi, 5 )
                            * std::pow( kB, 4 ) /
                ( 15.0 * std::pow( h, 3 ) * std::pow( c, 2 ) );
 
//------------------------------------------------------------------------------

        const real L0 = std::pow( pi * kB / e , 2 ) / 3.0 ;
 
//------------------------------------------------------------------------------
// EARTH
//------------------------------------------------------------------------------

        const real g0 = 9.80665;
 
//------------------------------------------------------------------------------

        const real mu_earth = 3.986004418e14;
 
//------------------------------------------------------------------------------

        const real R_earth = std::sqrt( mu_earth / g0 );
 
//------------------------------------------------------------------------------
// astronomy
//------------------------------------------------------------------------------
 
        // julian day number for 01/01/2000 00:00 UT
        const real y2k = 2451544.5 ;
 
        // Astronomical unit https://www.britannica.com/science/astronomical-unit
        const real AU = 149597870700. ;
 
 
    }
}
 
#if defined(__clang__)
#pragma clang diagnostic pop
#elif defined(__GNUC__) || defined(__GNUG__)
#pragma GCC diagnostic pop
#endif
 
#endif //BELFEM_CONSTANTS_HPP