#ifndef SPHERE_ADAPT_FUNCTIONS_H
#define SPHERE_ADAPT_FUNCTIONS_H

/* Define the Sphere data structure 
  for magnetic anomaly calculation
  */
typedef struct {
    double northing;  // northing coordinate of the sphere center (m)
    double easting;    // easting coordinate of the sphere center (m)
    double z; // depth to sphere center (m)
    double a; // radius of the sphere (m)
    double minc; //inclination of the vector of magnetization of the sphere (degrees)
    double mdec; //inclination of the vector of magnetization of the sphere (degrees)
    double mi; //intensity of the vector of magnetization of the sphere (amp/m)
    double einc; //inclination of the Earth's magnetic field (degrees)
    double edec; //declination of the Earth's magnetic field (degrees)
} Sphere;

/* Define the Datapoint data structure
   to hold the easting, northing, and mag values
   for magnetic observations and calculated mag values
   */
typedef struct {
    double northing; //northing coordinate of the observation point (m)
    double easting; //easting coordinate of the observation point (m)
    double mag_obs; //total field magnetic anomaly at observation point (nT)
    double mag_calc; // calculated magnetic anomaly at obs point (nT, may initially be 0.0)
} DataPoint;


/* declare the functions used in the sphere inversion code */

double magnetized_sphere_anomaly(double x, double y, Sphere sphere);
double calculate_rmse(DataPoint *mag_anomaly, int size);
double coarse_to_fine_search(DataPoint *mag_anomaly, Sphere *sphere, int size, double z_min, double z_max, int grid_points);
double adaptive_gradient_search(DataPoint *mag_anomaly, Sphere *sphere, int size, double alpha_init, double tol, int max_iter);
int read_data_file(const char *filename, DataPoint **mag_anomaly, int *row_count);

#endif