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codebucketdev/Shifting.java

Created September 25, 2014 19:45
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  1. @divadsn divadsn created this gist Sep 25, 2014.
    218 changes: 218 additions & 0 deletions Shifting.java
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,218 @@
    package de.codebucket.math;

    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.util.ArrayList;
    import java.util.List;
    import java.util.Random;
    import java.util.concurrent.atomic.AtomicBoolean;

    public class Shifting
    {
    private double value;

    public Shifting(double value)
    {
    this.value = value;
    }

    public double getValue()
    {
    return value;
    }

    private static final Random random = new Random(System.currentTimeMillis());

    public List<Result> calculate()
    {
    double x = (random.nextInt(12) + 1), y = (this.value / x), square = (x * y);
    List<Result> results = new ArrayList<Shifting.Result>();
    Result lastResult = new Result(x, y);
    results.add(lastResult);

    while(!lastResult.isSimilar())
    {
    double newY = ((lastResult.getX() + lastResult.getY()) / 2);
    double newX = (double) (square / newY);
    if(lastResult.getX() == newX && lastResult.getY() == newY)
    {
    lastResult = new Result(0, 0);
    break;
    }

    Result result = new Result(newX, newY);
    lastResult = result;
    results.add(result);

    System.gc();
    }

    return results;
    }

    protected static class Result
    {
    double x, y;

    public Result(double x, double y)
    {
    this.x = x;
    this.y = y;
    }

    public double getX()
    {
    return x;
    }

    public double getY()
    {
    return y;
    }

    public boolean isSimilar()
    {
    return (x == y);
    }

    @Override
    public String toString()
    {
    return "Result(x: " + x + ", y: " + y + ")";
    }
    }

    private static int exit = -1;

    public static void main(String[] args)
    {
    System.out.println("Das Heronverfahren, nachprogrammiert in Java.");
    System.out.println("Version 1.1, kompiliert am 25.09.2014 um 19:23.");
    System.out.println("(C) Copyright Codebucket 2014\n");

    Runtime.getRuntime().addShutdownHook(new Thread()
    {
    public void run()
    {
    if(exit == -1)
    {
    System.err.print("\n\nDer Berechnungsprozess wurde vom Benutzer abgebrochen.");
    return;
    }
    }
    });

    String square = (args.length == 1 ? args[0] : null);
    if(args.length == 0)
    {
    BufferedReader console = new BufferedReader(new InputStreamReader(System.in));
    System.out.print("Geben Sie eine Zahl ein: ");
    try
    {
    square = console.readLine();
    }
    catch (IOException e) {}
    }

    final AtomicValue value = new AtomicValue(0);
    try
    {
    value.set(Double.parseDouble(square));
    }
    catch(NumberFormatException ex)
    {
    System.err.println("'" + square + "' ist keine Zahl, kein Ergebnis!");
    Shifting.exit = 1;
    return;
    }

    System.out.print("Berechne Naeherungswert aus Wurzel " + value + "..");
    final AtomicBoolean ready = new AtomicBoolean(false);
    new Thread(new Runnable()
    {
    @Override
    public void run()
    {
    while(!ready.get())
    {
    System.out.print(".");
    try
    {
    Thread.sleep(1000);
    }
    catch (InterruptedException e) {}
    }
    }
    }).start();

    final Thread math = new Thread(new Runnable()
    {
    final long start = System.currentTimeMillis();

    @Override
    public void run()
    {
    Shifting shift = new Shifting(value.get());
    List<Result> results = shift.calculate();
    ready.set(true);

    System.out.println("\n\n<" + seperator() + ">");
    for(int i = 0; i < results.size(); i++)
    {
    Result result = results.get(i);
    System.out.println("Ergebnis #" + i);
    System.out.println("Zahl X: " + result.getX());
    System.out.println("Zahl Y: " + result.getY());
    System.out.println("\n<" + seperator() + ">");
    }

    Result end = results.get(results.size() - 1);
    System.out.println("\nNaeherungswert: " + end.getY() + ", Ergebnis: " + Math.sqrt(value.get()));
    System.out.println("Berechnet in " + (System.currentTimeMillis() - start) + "ms");

    Shifting.exit = 0;
    }
    }, "math");

    math.start();
    return;
    }

    private static class AtomicValue
    {
    private double value;

    public AtomicValue(double value)
    {
    this.value = value;
    }

    public double get()
    {
    return value;
    }

    public void set(double value)
    {
    this.value = value;
    }

    @Override
    public String toString()
    {
    return String.valueOf(value);
    }
    }

    private static String seperator()
    {
    StringBuilder builder = new StringBuilder(28);
    for(int i = 0; i < 28; i++)
    {
    builder.append("=");
    }

    return builder.toString();
    }
    }