import java.util.Arrays;

/**
 * Created by IntelliJ IDEA.
 * User: Andrew
 * Date: 28.03.12
 * Time: 0:12
 * To change this template use File | Settings | File Templates.
 */
public class GridBorderMain {
    public static double getP(double xk) {      //change
//      return 2 * xk;
        return 0;
    }

    public static double getQ(double xk) {      //change
        return -(xk * xk + 1);
    }

    public static double getA(double h, double xk) {
        return 1 - (h / 2) * getP(xk);
    }

    public static double getB(double h, double xk) {
        return h * h * getQ(xk) - 2;
    }

    public static double getC(double h, double xk) {
        return 1 + (h / 2) * getP(xk);
    }

    public static double getF(double xk) {      //change
        return 12 * xk - 2 * Math.pow(xk, 3) - 2 * Math.pow(xk, 5);
    }


    public static void main(String[] args) {
        double h = 0.1;
        double a0 = 1;  //alpha0                //change
        double a1 = 3;  //alpha1                //change
        double b0 = -1; //beta0                 //change
        double b1 = 1;  //beta1                 //change
        double A = 0;
        double B = 5;

        double l = 0;   // [l, g]              //change
        double g = 1;                          //change
        int n = ((int) ((g - l) / h)) + 1;

        double[] a = new double[n];
        double[] b = new double[n];
        double[] c = new double[n];
        double[] x = new double[n];
        double[] y = new double[n];
        double[] d = new double[n];

        double[] ksi = new double[n];
        double[] eta = new double[n];


        for (int i = 1; i < n; i++) {
            x[i] = x[i - 1] + h;
        }

        for (int i = 0; i < n; i++) {
            a[i] = getA(h, x[i]);
            b[i] = getB(h, x[i]);
            c[i] = getC(h, x[i]);
            d[i] = getF(x[i]) * h * h;
        }

        double a1S = a1 / (1 - h / 2 * getP(x[0]));
        double a0S = a0 * h - (a1 - h * getQ(x[0]) / 2) / (1 - h * getP(x[0]) / 2);
        double hAS = h * A + (h * h * getF(x[0]) / 2) / (1 - h * getP(x[0]) / 2);

        double b1S = b1 / (1 + h / 2 * getP(x[0]));
        double b0S = b0 * h - (b1 + h * getQ(x[n - 1]) / 2) / (1 + h * getP(x[n - 1]) / 2);
        double hBS = h * B + (h * h * getF(x[n - 1]) / 2) / (1 + h * getP(x[n - 1]) / 2);


        ksi[1] = -a1S / a0S;
        eta[1] = -hAS / a0S;

        for (int k = 1; k < ksi.length - 1; k++) {
            ksi[k + 1] = c[k] / (b[k] - ksi[k] * c[k]);
            eta[k + 1] = (a[k] * eta[k] - d[k]) / (b[k] - ksi[k] * c[k]);
        }

        y[n - 1] = (hBS - b0S * eta[n - 1]) / (b1S + b0S * ksi[n - 1]);

        for (int i = n - 2; i > 0; i--) {
            y[i] = ksi[i+1]*y[i+1]+eta[i+1];
        }

        y[0] = - ((a1S)/(a0S))*y[1] + hAS/(a0S);


        System.out.println("x: " + Arrays.toString(x));
        System.out.println("a: " + Arrays.toString(a));
        System.out.println("b: " + Arrays.toString(b));
        System.out.println("c: " + Arrays.toString(c));
        System.out.println("d: " + Arrays.toString(d));

        System.out.println("a1* = " + a1S);
        System.out.println("b1* = " + b1S);
        System.out.println("a0* = " + a0S);
        System.out.println("b0* = " + b0S);
        System.out.println("hA* = " + hAS);
        System.out.println("hB* = " + hBS);


        System.out.println("ksi: " + Arrays.toString(ksi));
        System.out.println("eta: " + Arrays.toString(eta));
        System.out.println("y: " + Arrays.toString(y));

    }
}