next up previous
Next: About this document ... Up: ORBIT9 USER GUIDE Version Previous: 5. POSTPROCESSING

6. STATEMENTS

1. This is free software, which can be copied and distributed by anyone interested, but cannot be sold and cannot be incorporated into commercial products. The copyright notice, containing the Free Software Foundation standard notice, must not be removed from any copy.

2. This software has been developed by A. Milani, who has in turn incorporated some free software developed by other people, mostly by M. Carpino (Astronomical Observatory, Milano/Brera). The author cannot take any responsability for the performance of this software, nor for its upgrade; the software maintenance of these codes must result from the collaboration of the users, who are kindly requested to report any error and/or limitation not already described here.

3. This software can be modified by the users at their own risk. The best effort has been done to make this not too difficult. I give here an example: suppose you want to manufacture a program to compute the orbits of the satellites of Saturn. Then you should 1) modify the right hand side of the differenctial equations (file fct9.f) to add the zonal harmonics of Saturn gravitational field; the latter will depend upon some parameters, called e.g. pj2, pj4. 2) modify the common contained in commas.h by adding pj2, pj4. 3) modify the routines reamas, wrimas in such a way that they also handle pj2, pj4 in input and output; there you can also change the choice of the units, by replacing Gauss constant gk with something else. 4) add new options to refer in coord.f to be able to refer the results to the planet's equatorial plane. 5) prepare suitable initial conditions files, in which the so called planets file will contain also the initial conditions for the more massive satellites, the so called asteroid file will contain the initial conditions for the small satellites; the inverse mass of Saturn must replace the inverse mass of the Sun, and the mass of the Sun will appear as the mass of a perturbing body. All this might appear complicated, but starting from scratch and writing all your own software is more complicated (although it is an instructive exercice).


next up previous
Next: About this document ... Up: ORBIT9 USER GUIDE Version Previous: 5. POSTPROCESSING
Andrea Milani
1999-10-31