Example usage of reb_add_fmt() (C)

The reb_add_fmt() function can be used to add a particle to the simulation by specifying the particle's coordinates in a variety of formats.

#include "rebound.h"
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char* argv[]) {
    struct reb_simulation* r = reb_create_simulation();

    // Central object at origin with mass=1
    reb_add_fmt(r, "m", 1.);

    // Massless particle on circular orbit with a=1
    reb_add_fmt(r, "a", 1.);

    // A Jupiter mass planet with a=2 and e=0.1
    reb_add_fmt(r, "m a e", 1e-3, 2., 0.1);

    // By default Jacobi coordinates are used, here we use
    // heliocentric coordinates by specifying the primary.
    reb_add_fmt(r, "a e primary", 0.1, 0.3, r->particles[0]);

    // The function supports any arbitrary combination of
    // orbital parameters as long as it's physically meaningful.
    reb_add_fmt(r, "a e omega", 3., 0.1, M_PI);
    reb_add_fmt(r, "a e pomega", 4., 0.1, M_PI/2.);
    reb_add_fmt(r, "P h k", 365.25, 0.01, 0.02);

    // Non-physical parameter combinations raise errors
    reb_add_fmt(r, "a e", -1., 0.1);
    reb_add_fmt(r, "a e", -1., 0.1);

    // Cartesian coordinates are supported as well
    reb_add_fmt(r, "m x vy", 1e-3, 9., 0.3);

    /** Supported parameters are:
     *       m:          Mass  (Default: 0)
     *       x, y, z:    Positions in Cartesian coordinates  (Default: 0)
     *       vx, vy, vz: Velocities in Cartesian coordinates (Default: 0)
     *       primary:    Primary body for converting orbital elements to cartesian (Default: center of mass of the particles in the passed simulation, i.e., this will yield Jacobi coordinates as one progressively adds particles)
     *       a:          Semimajor axis (a or P required if passing orbital elements)
     *       P:          Orbital period (a or P required if passing orbital elements)
     *       e:          Eccentricity                (Default: 0)
     *       inc:        Inclination                 (Default: 0)
     *       Omega:      Longitude of ascending node (Default: 0)
     *       omega:      Argument of pericenter      (Default: 0)
     *       pomega:     Longitude of pericenter     (Default: 0)
     *       f:          True anomaly                (Default: 0)
     *       M:          Mean anomaly                (Default: 0)
     *       E:          Eccentric anomaly           (Default: 0)
     *       l:          Mean longitude              (Default: 0)
     *       theta:      True longitude              (Default: 0)
     *       T:          Time of pericenter passage
     *       h:          h variable, see Pal (2009) for a definition  (Default: 0)
     *       k:          k variable, see Pal (2009) for a definition  (Default: 0)
     *       ix:         ix variable, see Pal (2009) for a definition  (Default: 0)
     *       iy:         iy variable, see Pal (2009) for a definition  (Default: 0)
     *       r:          Particle radius
     *
     * Note that it is important to pass floating point numbers and not integers to reb_add_fmt().
     * For example:
     *     reb_add_fmt(r, "a", 1)
     * will lead to undefined behaviour. Instead, use
     *     reb_add_fmt(r, "a", 1.0)
     */

    // Run a test simulation
    reb_move_to_com(r);
    reb_integrate(r,100.);
}

This example is located in the directory examples/reb_add_fmt