antras.java

Solving nonlinear equations using Newton s and Transversal methods for function x=exp(-x^2)

/***********************************************
 *   Skaitiniu metodu 2 laboratorinis darbas   *
 *       Netiesiniu uzdaviniu sprendimas       *
 *     Relaksacijos ir kirstiniu metodais      *
 *         Uzduotis - x = exp(-x ^ 2)          *
 *       Autorius - Vaidas Zidanavicius        *
 **********************************************/

import java.io.*;
import java.lang.*;

public class Antras {
    
    public static double G_a, G_b, G_x0, G_x1, G_y0, G_y1;
    
    public Antras() {
        
    }
    
    public static double Nuskaitymas_Double() {
        String tmp="";
	double skaiciukas=0;
	try {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            tmp=br.readLine();
	}
	catch (IOException exc) {
            System.out.println("Skaitymo klaida: "+exc);
            System.exit(0);
	}
	try {
            skaiciukas = Double.parseDouble(tmp);
        }
        catch (NumberFormatException exc) {
            System.out.println("Blogas skaitmuo. Stringas  "+tmp+ " yra ignoruotas.");
	}
            return skaiciukas;
    }
    
    public static int Nuskaitymas_Int() {
        String tmp="";
	int skaiciukas=0;
	try {
            BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
            tmp=br.readLine();
	}
	catch (IOException exc) {
            System.out.println("Skaitymo klaida: "+exc);
            System.exit(0);
	}
	try {
            skaiciukas = Integer.parseInt(tmp);
        }
        catch (NumberFormatException exc) {
            System.out.println("Blogas skaitmuo. Stringas  "+tmp+ " yra ignoruotas.");
	}
            return skaiciukas;
    }
    
    public static double Funkcija(double x) {
        double y=((-1)*Math.cos(x)-x);
        return y;
    }
    
    public static double Funkcija2(double x) {
        double y=((-1)*Math.cos(x));
        return y;
    }
    
    public static void Relaksacija() {
        double L_x1, L_y1, omega, M, m, Eps;
        int i = 0;
        System.out.println("Iveskite intervalo pradzia:");
        G_a = Nuskaitymas_Double();
        System.out.println("Iveskite intervalo gala:");
        G_b = Nuskaitymas_Double();
        System.out.println("Iveskite x_0 reiksme:");
        G_x0 = Nuskaitymas_Double();
        G_y0 = Funkcija2(G_x0);
        M=3;
        m=0;
        omega=2/(2+M+m);
        Eps = 0.001;
        L_x1 = (((1-omega)*G_x0)+(omega*G_y0));
        L_y1 = Funkcija(L_x1);
        int j = i;
        System.out.println("x_"+j+"="+G_x0);
        j++;
        System.out.println("x_"+j+"="+L_x1);
        while (!((L_y1==0) || ((Math.abs(L_x1-G_x0))<Eps))) {
            i++;
            G_x0 = L_x1;
            G_y0 = Funkcija2(G_x0);
            L_x1 = (((1-omega)*G_x0)+(omega*G_y0));
            L_y1 = Funkcija(L_x1);
            j = i;
            j++;
            System.out.println("x_"+j+"="+L_x1);
        }
        System.out.println("Relaksacijos metodo sprendinys: "+L_x1);
    }
    
    public static void Kirstine() {
        double Eps=0.001;
        double L_x2, L_y2;
        int i=0;
        int j;
        System.out.println("Iveskite x_0 reiksme:");
        G_x0 = Nuskaitymas_Double();
        System.out.println("Iveskite x_1 reiksme:");
        G_x1 = Nuskaitymas_Double();
        G_y0 = Funkcija(G_x0);
        G_y1 = Funkcija(G_x1);
        L_x2 = G_x1 - (G_y1*((G_x1-G_x0)/(G_y1-G_y0)));
        L_y2 = Funkcija(L_x2);
        j = i;
        System.out.println("x_"+j+"="+G_x0);
        j++;
        System.out.println("x_"+j+"="+G_x1);
        j++;
        System.out.println("x_"+j+"="+L_x2);
        while (!((L_y2==0) || ((Math.abs(L_x2-G_x1))<Eps))) {
            i++;
            G_x0 = G_x1;
            G_x1 = L_x2;
            G_y0 = Funkcija(G_x0);
            G_y1 = Funkcija(G_x1);
            L_x2 = G_x1 - (G_y1*((G_x1-G_x0)/(G_y1-G_y0)));
            L_y2 = Funkcija(L_x2);
            j = i;
            j = j+2;
            System.out.println("x_"+j+"="+L_x2);
        }
        System.out.println("Kirstiniu metodo sprendinys: "+L_x2);
    }
    
    public static void main(String[] args) {
        G_a = G_b = G_x0 = G_x1 = G_y0 = G_y1 = 0;
        int meniu;
        System.out.println("1 - Relaksacijos metodu; 2 - Kirstiniu metodu; 0 - Exit: ");
        meniu = Nuskaitymas_Int();
        while (meniu != 0) {
	        if (meniu==1){
	            Relaksacija();
	            System.out.println("1 - Relaksacijos metodu; 2 - Kirstiniu metodu; 0 - Exit: ");
        		meniu = Nuskaitymas_Int();
	        }
	        else if (meniu==2) {
	            Kirstine();
	            System.out.println("1 - Relaksacijos metodu; 2 - Kirstiniu metodu; 0 - Exit: ");
        		meniu = Nuskaitymas_Int();
	        }
	        else {
	            System.out.println("Ivedete bloga skaiciu.");
	            //System.exit(0);
	            System.out.println("1 - Relaksacijos metodu; 2 - Kirstiniu metodu; 0 - Exit: ");
        		meniu = Nuskaitymas_Int();
	        }
	    }
    }
    
}