Добавлена пятая лабораторная работа

src/Main.java

@@ -17,7 +17,7 @@ import javax.swing.border.EmptyBorder;
  */
 public class Main extends JFrame {
     
-    private static final int NUM_OF_LABS = 4;
+    private static final int NUM_OF_LABS = 5;
     
     public static void main(String[] args) {
         try {

src/com/nummethods/lr4/LR_4.java

@@ -2,7 +2,6 @@ package com.nummethods.lr4;
 
 import java.awt.Dimension;
 import javax.swing.JFrame;
-import static javax.swing.JFrame.EXIT_ON_CLOSE;
 
 /**
  * v10

src/com/nummethods/lr5/EulerMethod.java

@@ -0,0 +1,22 @@
+package com.nummethods.lr5;
+
+import java.awt.geom.Point2D;
+
+/**
+ * Ìåòîä Ýéëåðà.
+ * @author aNNiMON
+ */
+public class EulerMethod extends IntegrateMethod {
+
+    public EulerMethod(Integral integral) {
+        super(integral);
+    }
+
+    @Override
+    protected double integrate(double xi, double h, double x0, double v0) {
+        double vi = (isEquals(xi, x0)) ? v0 : integrate(xi-h, h, x0, v0);
+        points.add(new Point2D.Double(xi, vi));
+        return vi + h * integral.f(xi, vi);
+    }
+    
+}

src/com/nummethods/lr5/Function.java

@@ -0,0 +1,9 @@
+package com.nummethods.lr5;
+
+/**
+ * @author aNNiMON
+ */
+public interface Function {
+   
+    double f(double x, double v);
+}

src/com/nummethods/lr5/Integral.java

@@ -0,0 +1,41 @@
+package com.nummethods.lr5;
+
+/**
+ * @author aNNiMON
+ */
+public class Integral implements Function {
+    
+    private final Function func;
+    private final double v0, x0, xN;
+    private final int N;
+    
+    public Integral(Function func, double v0, double x0, double xN, int N) {
+        this.func = func;
+        this.v0 = v0;
+        this.x0 = x0;
+        this.xN = xN;
+        this.N = N;
+    }
+    
+    @Override
+    public double f(double x, double v) {
+        return func.f(x, v);
+    }
+
+    public double getX0() {
+        return x0;
+    }
+
+    public double getXN() {
+        return xN;
+    }
+
+    public double getV0() {
+        return v0;
+    }
+
+    public int getN() {
+        return N;
+    }
+    
+}

src/com/nummethods/lr5/IntegrateMethod.java

@@ -0,0 +1,39 @@
+package com.nummethods.lr5;
+
+import java.awt.geom.Point2D;
+import java.util.ArrayList;
+
+/**
+ * @author aNNiMON
+ */
+public abstract class IntegrateMethod {
+    
+    protected final Integral integral;
+    protected final ArrayList<Point2D> points;
+    
+    public IntegrateMethod(Integral integral) {
+        this.integral = integral;
+        this.points = new ArrayList<Point2D>();
+    }
+    
+    public double calculate(int n) {
+        double h = (integral.getXN() - integral.getX0()) / n;
+        return integrate(integral.getXN(), h, integral.getX0(), integral.getV0());
+    }
+    
+    protected abstract double integrate(double xi, double h, double x0, double v0);
+    
+    public Integral getIntegral() {
+        return integral;
+    }
+    
+    public Point2D[] getPoints() {
+        Point2D[] array = new Point2D[points.size()];
+        array = points.toArray(array);
+        return array;
+    }
+    
+    protected boolean isEquals(double a, double b) {
+        return Math.abs(a - b) < 0.00001;
+    }
+}

src/com/nummethods/lr5/LR_5.java

@@ -0,0 +1,107 @@
+package com.nummethods.lr5;
+
+import java.awt.Color;
+import java.awt.Dimension;
+import java.awt.Graphics;
+import java.awt.geom.Point2D;
+import javax.swing.JFrame;
+import util.GraphicPanel;
+
+/**
+ *
+ * @author aNNiMON
+ */
+public class LR_5 extends JFrame {
+    
+    private static final Integral var2 = new Integral(new Function() {
+
+            @Override
+            public double f(double x, double v) {
+                return Math.sin(x);
+            }
+        }, 0, -Math.PI, Math.PI, 50); // -0.006 | 4.386
+    
+    private static final Integral var10 = new Integral(new Function() {
+
+            @Override
+            public double f(double x, double v) {
+                return Math.log(x);
+            }
+        }, 0, 1, 5, 100); // 4.106 | 4.079
+    
+    private static final Integral var12 = new Integral(new Function() {
+
+            @Override
+            public double f(double x, double v) {
+                return 1 / (x);
+            }
+        }, 0, 1, 5, 75);
+    
+    public static void main(String[] args) {
+        new LR_5().setVisible(true);
+    }
+
+    public LR_5() {
+        super("LR_5");
+        setDefaultCloseOperation(DISPOSE_ON_CLOSE);
+        
+        final Integral integral = var10;
+        
+        IntegrateMethod runge = new RungeKuttaMethod(integral);
+        System.out.println("Runge-Kutta: " + runge.calculate(integral.getN()));
+        final Point2D[] rungePoints = runge.getPoints();
+        
+        IntegrateMethod euler = new EulerMethod(integral);
+        System.out.println("Euler: " + euler.calculate(integral.getN()));
+        final Point2D[] eulerPoints = euler.getPoints();
+        
+        GraphicPanel panel = new GraphicPanel() {
+            
+            
+            private int xOld, yOld;
+
+            @Override
+            protected void drawLabels(Graphics g, double x) {
+                g.setColor(Color.BLACK);
+                g.drawString("x: " + x, 10, 20);
+                g.setColor(Color.BLUE);
+                g.drawString("Runge-Kutta: " + findPoint(rungePoints, x), 10, 40);
+                g.setColor(new Color(0x00C000));
+                g.drawString("Cubic Spline: " + findPoint(eulerPoints, x), 10, 60);
+            }
+
+            @Override
+            protected void plot(Graphics g, double x, double y, boolean firstIteration) {
+                if (firstIteration) {
+                    // Ïåðâàÿ èòåðàöèÿ - çàïîìèíàåì êîîðäèíàòó
+                    xOld = (int) x;
+                    yOld = (int) y;
+                    return;
+                }
+                g.fillRect(xOld - 1, yOld - 1, 3, 3);
+                g.drawLine(xOld, yOld, (int) x, (int) y);
+                xOld = (int) x;
+                yOld = (int) y;
+            }
+        };
+        panel.addPoints(rungePoints);
+        panel.addPoints(eulerPoints);
+        
+        
+        panel.setPreferredSize(new Dimension(400, 300));
+        add(panel);
+        
+        pack();
+        setLocationRelativeTo(null);
+    }
+    
+    private double findPoint(Point2D[] array, double x) {
+        for (int i = 0; i < array.length; i++) {
+            double dx = Math.abs( array[i].getX() - x );
+            if (dx < 0.001) {
+                return array[i].getY();
+            }
+        }
+        return 0;
+    }
+}

src/com/nummethods/lr5/RungeKuttaMethod.java

@@ -0,0 +1,43 @@
+package com.nummethods.lr5;
+
+import java.awt.geom.Point2D;
+
+/**
+ * Ěĺňîä Đóíăĺ-Ęóňňű
+ * @author aNNiMON
+ */
+public class RungeKuttaMethod extends IntegrateMethod {
+
+    public RungeKuttaMethod(Integral integral) {
+        super(integral);
+    }
+
+    @Override
+    public double integrate(double xi, double h, double x0, double v0) {
+        double vi = isEquals(xi, x0) ? v0 : integrate(xi-h, h, x0, v0);
+        double k1 = k1(h, xi, vi);
+        double k2 = k2(h, xi, vi, k1);
+        double k3 = k3(h, xi, vi, k2);
+        double k4 = k4(h, xi, vi, k3);
+
+        points.add(new Point2D.Double(xi, vi));
+        return vi + (k1 + 2 * k2 + 2 * k3 + k4) / 6;
+    }
+    
+    private double k1(double h, double x, double v) {
+        return h * integral.f(x, v);
+    }
+
+    private double k2(double h, double x, double v, double k1) {
+        return h * integral.f(x + h / 2, v + k1 / 2);
+    }
+
+    private double k3(double h, double x, double v, double k2) {
+        return h * integral.f(x + h / 2, v + k2 / 2);
+    }
+
+    private double k4(double h, double x, double v, double k3) {
+        return h * integral.f(x + h / 2, v + k3 / 2);
+    }
+    
+}

src/util/GraphicPanel.java

@@ -81,7 +81,7 @@ public abstract class GraphicPanel extends JPanel {
             
             for (int i = 0; i < input.length; i++) {
                 Point2D p = input[i];
-                plot(g, (p.getX() - xMin) * dx, height - (p.getY() - yMin) * dy);
+                plot(g, (p.getX() - xMin) * dx, height - (p.getY() - yMin) * dy, i == 0);
             }
         }
         
@@ -97,7 +97,7 @@ public abstract class GraphicPanel extends JPanel {
     
     protected abstract void drawLabels(Graphics g, double x);
     
-    protected void plot(Graphics g, double x, double y) {
+    protected void plot(Graphics g, double x, double y, boolean firstIteration) {
         g.drawLine((int) x, (int) y, (int) x, (int) y);
     }