sphericalharmonicsutils.h

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/* ADDITIONAL COPYRIGHT NOTICE
 * The header accompanying the original file from which these functions are derived
   is as follows:                                                     */
/*    This file is distributed with 42,                               */
/*    the (mostly harmless) spacecraft dynamics simulation            */
/*    created by Eric Stoneking of NASA Goddard Space Flight Center   */
/*    Copyright 2010 United States Government                         */
/*    as represented by the Administrator                             */
/*    of the National Aeronautics and Space Administration.           */
/*    No copyright is claimed in the United States                    */
/*    under Title 17, U.S. Code.                                      */
/*    All Other Rights Reserved.                                      */
#ifndef UTILS_SPHERICALHARMONICSUTILS_H
#define UTILS_SPHERICALHARMONICSUTILS_H
 
#include <string>
 
#include "core/CartesianVector.hpp"
#include "core/mathmacros.h"
 
namespace warptwin {
    // Constants for spherical harmonics
    const int NMAX_SPHERICAL_HARMONICS = 18;

    int readGravityCoefficientsFile(const std::string &filename, 
                                    double cbar[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1],
                                    double sbar[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1],
                                    long int &n, long int &m);

    void neumannNormalization(double cbar[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1],
                              double sbar[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1],
                              double c[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1],
                              double s[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1]);

    int sphericalHarmonics(long N, long M, double r, double phi,
                           double theta, double Re, double K,
                           double C[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1], 
                           double S[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1],
                           CartesianVector3 &grad_v); 

    int legendre(long N, long M, double x,
                 double P[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1], 
                 double sd_p[NMAX_SPHERICAL_HARMONICS+1][NMAX_SPHERICAL_HARMONICS+1]);

    double fact(long n); 

    double oddfact(long n);
}
 
#endif