Library interface

A simple example program

The following example program shows the typical usage of the Octave/Matlab interface.

Other examples using the Octave/Matlab interface can be found in the directory examples of the library sources.

peph = CalcephBin.open('example1.dat');
AU = peph.getconstant('AU')
jd0 = 2451542
dt = 0.5
PV = peph.compute_unit(jd0, dt, NaifId.MOON, NaifId.EARTH,
                       Constants.UNIT_KM+Constants.UNIT_SEC+Constants.USE_NAIFID);
disp(PV)
peph.close();

Package

It is designed to work with Matlab or Octave software.

With Octave, you should load this package :

pkg load calcephoct

If you want Octave to automatically load this package, simply add to the file octaverc the command pkg load calcephoct .

With Matlab, you should add the path to the Matlab files of the dynamic library CALCEPH :

addpath('<prefix>/libexec/calceph/mex/')

By default, this prefix is /usr/local, so you have to enter before using calceph library.

addpath('/usr/local/libexec/calceph/mex/')

If you want Matlab to automatically add this path at startup, simply add to this path to the environment variable MATLABPATH.

Relative to C or Fortran interface, the prefixes calceph_, CALCEPH_, NAIFID_ are deleted for the naming convention of the functions, constants and NAIF identification numbers.

Types

class CalcephBin

This type contains all information to access a single ephemeris file or a set of files to be used together.

class NaifId

This type contains the NAIF identification numbers.

class Constants

This type contains all constants defined in the library, except the NAIF identification numbers.

Constants

The following constants are defined in the class Constants.

VERSION_MAJOR

This integer constant defines the major revision of this library. It can be used to distinguish different releases of this library.

VERSION_MINOR

This integer constant defines the minor revision of this library. It can be used to distinguish different releases of this library.

VERSION_PATCH

This integer constant defines the patch level revision of this library. It can be used to distinguish different releases of this library.

VERSION_STRING

This string is the version of the library, which can be compared to the result of calceph_getversion to check at run time if the header file and library used match:

Note: Obtaining different strings is not necessarily an error, as in general, a program compiled with some old CALCEPH version can be dynamically linked with a newer CALCEPH library version (if allowed by the operating system).

ASTEROID

This integer defines the offset value for the asteroids that must be used as target or center for the computation functions, such as CalcephBin.compute().

The following constants specify in which units are expressed the output of the computation functions, such as CalcephBin.compute_unit() :

UNIT_AU

This integer defines that the unit of the positions and velocities is expressed in astronomical unit.

UNIT_KM

This integer defines that the unit of the positions and velocities is expressed in kilometer.

UNIT_DAY

This integer defines that the unit of the velocities or the quantity TT-TDB or TCG-TCB is expressed in day (one day=86400 seconds).

UNIT_SEC

This integer defines that the unit of the velocities or the quantity TT-TDB or TCG-TCB is expressed in second.

UNIT_RAD

This integer defines that the unit of the angles is expressed in radian.

OUTPUT_EULERANGLES

This integer defines that the output array contains the euler angles.

OUTPUT_NUTATIONANGLES

This integer defines that the output array contains the nutation angles.

USE_NAIFID

This integer defines that the NAIF identification numbers are used as target or center for the computation functions, such as CalcephBin.compute_unit().

The following constants specify the type of segments for the functions, such as calceph_getmaxsupportedorder() :

SEGTYPE_ORIG_0

This integer defines the type of segment for the original INPOP/JPL DE file format.

SEGTYPE_SPK_1

SEGTYPE_SPK_2

SEGTYPE_SPK_3

SEGTYPE_SPK_5

SEGTYPE_SPK_8

SEGTYPE_SPK_9

SEGTYPE_SPK_12

SEGTYPE_SPK_13

SEGTYPE_SPK_14

SEGTYPE_SPK_17

SEGTYPE_SPK_18

SEGTYPE_SPK_19

SEGTYPE_SPK_20

SEGTYPE_SPK_21

SEGTYPE_SPK_102

SEGTYPE_SPK_103

SEGTYPE_SPK_120

This integer defines the type of segments (1, 2, 3, 5, 8, 9, 12, 13, 14, 17, 18, 20, 21, 102, 103 and 120) for the SPICE Kernel files.