#/* File: FI.C */

#include<stdlib.h>
#include "fi.h"
#include <math.h>
#include <stdio.h>

//#define P 10 /* number of parameters a */
#define P 5

//#define T 252 /* number of data entries
#define T 460

#define DATAFILE "data.txt"
#define epsilon 0.0

const int K = 100;		//diskretizacijos tasku skaicius
static double z[T];
static double a[P], c, mu, si;
const double *b ;
int number_of_variables = P+3;


double Gaussian(double y)		//gauso pasiskirstymo funkcija taske y
{
	double delta;
	double si3 = 3 * si;
	delta = si3 / K;
	int iy = ceil(y / delta);
//	int iy = y / delta;
	double sum = 0.0;

	for(int i = -K; i < iy; i++)
		sum = sum + exp(-0.5 * pow(((delta * i) - mu) / si, 2));
	sum = sum * (1.0 / (sqrt(6.28) * si));
	return sum / (2 * K);
}

void get_z ()
{
	FILE* fp = fopen (DATAFILE,"r");
	for ( int t = 0; t < T; t++ )
		fscanf ( fp, "%lg", &z[t] );
	fclose (fp);
}

double art(int t)
{
	double psum = 0.0;
	for ( int i = 0; i < P; i++ )
		psum = psum + a[i] * z[t-i];
	return psum;
}

double eps2sum()
{
	double eps2 = 0;
	double dif;
	for ( int j = P; j < T; j++ )
	{
		dif = z[j] - c * Gaussian(art(j));
		eps2 = eps2 + dif * dif; //pow (dif[j],2);
	}
	return eps2;
}

/* Goal function definition */
/* First Q x-ses are b's, last one is d */

double fi (const double *x, int n)
{
	c  = x[0];
	mu = x[1];
	si = x[2];
	get_z();
	for ( int j = 0; j < P; j++ )
		a[j] = x[j+3];

	return (eps2sum() + epsilon);
}


void constr (const double *x, int n, double *g, int ng)
{
/*
ng > 0 - calculates all constaints
ng < 0  - calculates only constraint with number (-ng)
	*/
	/*   double x1 = x [0];
	double x2 = x [1];
	double x3 = x1 * x1;
	double x4 = x2 * x2;

	  if (ng > 0) {
	  g [0] = 25. - x3 - x4;
	  g [1] = 10. * x1 - x3 + 10. * x2 - x4 - 34.;
	  g [2] = x1;
	  g [3] = x2;
	  } else {
	  ng = -ng;
	  switch (ng) {
	  case 1:
	  g [0] = 25. - x3 - x4;
	  break;
	  case 2:
	  g [1] = 10. * x1 - x3 + 10. * x2 - x4 - 34.;
	  break;
	  case 3:
	  g [2] = x1;
	  break;
      case 4:
	  g [3] = x2;
	  break;
      }
} */
	if ( ng > 0 ) 
		for ( int i = 0 ; i < n ; i++ ) g[i] = 0 ;
		else g[-ng] = 0 ;
		
}