forum.alglib.net

ude <cstdlib>

#include <cstdio>

#include <cmath>

#include <string>

#include <vector>

#include <fstream>

#include <iostream>

#include "interpolation.h"

using namespace alglib;

void function_cx_1_func(const real_1d_array &c, const real_1d_array &x, double &func, void *ptr)

{

// this callback calculates f(c,x)=exp(-c0*sqr(x0))

// where x is a position on X-axis and c is adjustable parameter

func = c[0] * sin( 2 * 3.14159 * c[1] * x[0] + c[2]) + c[3];

}

int main(int argc, char **argv)

{

//

using std::cout;

using std::endl;

const std::string infile="/path/to/data";

std::vector<double> vx;

std::vector<double> vy;

std::ifstream data(infile.c_str());

while (!data.eof() || !data.fail()) {

double xx(0),yy(0);

data >> xx >> yy ;

if (data.fail()) break;

vx.push_back(xx);

vy.push_back(yy);

}

data.close();

real_1d_array c = "[2.5, 0.5, 0., 0.]"; //this is a rough guess but shouldn't be so wrong
//Setting parameters from input file too x,y array, I don't know the lib but I am confident I did it the right way
real_2d_array x;

x.setcontent(vx.size(), 1, &vx.front());

real_1d_array y;

y.setcontent(vy.size(), &vy.front());

double epsf = 0;

double epsx = 0.0001;

ae_int_t maxits = 0;

ae_int_t info;

lsfitstate state;

lsfitreport rep;

double diffstep = 0.0001;

//

// Fitting without weights

//

lsfitcreatef(x, y, c, 0.01, state); //played with params


lsfitsetcond(state, epsf, epsx, maxits);

alglib::lsfitfit(state, function_cx_1_func);

lsfitresults(state, info, c, rep);

cout << info << endl;

// cout << x.tostring(1) << endl;

// cout << y.tostring(1) << endl;

std::cout << c[0] << "* sin (2 pi " << c[1] <<"x + " << c[2] << ") + " << c[3] <<std::endl;

std::cout << rep.errpar[0] << " " << rep.errpar[1] << " " << rep.errpar[2] << " " << rep.errpar[3] << std::endl;


return 0;

}