/*
 * h1c.java - revised 18 Apr 05 - width 461, height 285
 * @author jackord@kw.igs.net
 * companion program to cat.java showing the parameter variation sequence
 *   (a) used in cat.java  (thread sleeps 10 ms per trial)
 *   (b) in the simplex algorithm  (thread sleeps 100 ms per trial)
 * the catenary constants are also refined using the simplex algorithm
 */

import java.applet.Applet;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class h1c extends Applet 
                  implements ActionListener, Runnable {
  int n, phi, nvr, nvx; int kk=0; int r=3; int del=0;  // Declarations
  double s, tns, dtns, d;
  double[][] q=new double[9][6];
  String b1s="Vary"; Button b1=new Button(b1s);
  String b2s="Simp"; Button b2=new Button(b2s);
  String b3s="Catc"; Button b3=new Button(b3s);
  TextField tx1=new TextField(10);
  TextField tx2=new TextField(10);
  TextField tx3=new TextField(10);
  Thread tmr;

  public void init() {
    add(b1); add(b2); add(b3); add(tx1); add(tx2); add(tx3);
    b1.addActionListener(this); b2.addActionListener(this);
    b3.addActionListener(this);
    setBackground(new Color(211, 211, 211));
    tx1.setBackground(getBackground());
    tx2.setBackground(getBackground());
    tx3.setBackground(getBackground());
  }

  public void start() {                                // Graphics thread
    if (tmr==null) {
      tmr=new Thread(this);
      tmr.setPriority(Thread.MIN_PRIORITY);
      tmr.start();
    }
  }

  public void stop() {
    tmr=null; kk=0;
  }

  public void run() {
    repaint();
  }

  public void hit(int ii, Graphics g) {                // Trace out string
    double x, y, p, t, tn, tc;
    if (kk==3) {
      x=q[ii][2]+q[ii][3]*cosh((10-q[ii][1])/q[ii][3])-230;
      y=q[ii][2]+q[ii][3]*cosh((250-q[ii][1])/q[ii][3])-110;
      p=q[ii][3]*(sinh((250-q[ii][1])/q[ii][3])-sinh((10-q[ii][1])/q[ii][3]))-400;
      s=Math.sqrt((x*x+y*y+p*p)/3);
    }
    else {
      x=10; y=10; t=tns; p=phi*Math.PI/18000;          // First angle & tension
      if (kk==2) {
        p=q[ii][1]*Math.PI/18000; t=q[ii][2];
      }
      tn=Math.tan(p); tc=t*Math.cos(p);
      x=x+d*Math.cos(p); y=y-d*Math.sin(p); 
      g.fillArc(xs(-p*180/Math.PI)-r, ys(t)-r, 2*r, 2*r, 0, 360);
      for (int i=1; i<=n; i=i+1) {                     // Loop
        tn=tn+1/tc; p=Math.atan(tn); t=tc/Math.cos(p); // Next angle & tension
        x=x+d*Math.cos(p); y=y-d*Math.sin(p);
      }
      s=Math.sqrt((x-250)*(x-250)+(y-130)*(y-130));
      try {                                            // Graphics time delay
        Thread.sleep(del);
      }
      catch (InterruptedException e) {
        stop();
      }
    }
  }

  public void ang(Graphics g) {                        // Find optimum angle
    double so; int dph=-256;
    do {
      phi=phi+dph; so=s; hit(1, g);
      if (s>so) { dph=-dph/2; }
    } while (Math.abs(dph)>1);
    phi=phi+2*dph; hit(1, g);
  }

  double cosh(double x) {                              // Cosh(x)
    return (Math.exp(x)+Math.exp(-x))/2;
  }

  double sinh(double x) {                              // Sinh(x)
    return (Math.exp(x)-Math.exp(-x))/2;
  }

  int xs(double x) {
    return 48+(int)((x-58)*400./22);
  }

  int ys(double y) {
    return 242-(int)((y-40)*230./12);
  }

  public void pin(Graphics g) {                        // Initialize screen
    if (kk==0) {
      b1.setBounds(53, 167, 40, 20); b2.setBounds(53, 192, 40, 20);
      b3.setBounds(53, 217, 40, 20); tx1.setBounds(98, 167, 80, 20);
      tx2.setBounds(98, 192, 80, 20); tx3.setBounds(98, 217, 80, 20);
    }
    g.setColor(Color.black); g.drawRect(48, 12, 400, 230);
    g.drawString("40", 28, 248); g.drawString("52", 28, 18);
    g.drawString("tension", 4, 133); g.drawString("angle", 224, 278);
    g.drawString("58", 40, 262); g.drawString("80", 440, 262);
  }  

  public void paint(Graphics g) {                      // Paint
    double so;
    pin(g);
    n=64; d=400./(n+1); phi=-6000; tns=48; dtns=2;
    g.setColor(Color.red); hit(1, g);
    tx1.setText("phi = "+(-phi/100.));
    tx2.setText("tns = "+(int)(100*tns)/100.);
    tx3.setText("dev = "+(int)(100*s)/100.);
    if (kk==1) {
      g.setColor(Color.blue); ang(g);
      tx3.setText("Dev = "+(int)(100*s)/100.);
      do {                                             // Vary initial tension
        tns=tns+dtns; so=s; ang(g);                    // ... and angle
        tx1.setText("phi = "+(-phi/100.));
        tx2.setText("tns = "+(int)(100*tns)/100.);
        tx3.setText("dev = "+(int)(100*s)/100.);
        if (s>so) { dtns=-dtns/2; }
      } while ((s>.1)&&(kk>0));                        // ... to reach support
      g.setColor(Color.red); hit(1, g);
    }
    if (kk==2) {
      g.setColor(Color.red); sim(g);
    }
    if (kk==3) {
      sim(g);
    }
    stop();
  }

  public void sim(Graphics g) {                        // Simplex algorithm
    int ii=0; int iv=0; int jlof=0; int xflag;
    double ave, nexp, lim;
    if (kk==2) {
      nvr=2; nvx=nvr+1; lim=0.1;
      q[1][1]=phi; q[1][2]=tns;
      q[2][1]=phi-256; q[2][2]=tns;
      q[3][1]=phi; q[3][2]=tns+dtns;
    }
    else {
      nvr=3; nvx=nvr+1; lim=0.00001;
      q[1][1]=152; q[1][2]=-42; q[1][3]=69;
      q[2][1]=153; q[2][2]=-42; q[2][3]=69;
      q[3][1]=152; q[3][2]=-41; q[3][3]=69;
      q[4][1]=152; q[4][2]=-42; q[4][3]=70;
    }
    for (int i=1; i<=nvx; i=i+1) {
      hit(i, g); q[i][0]=s;
    }
    sort(g);
    while ((q[1][0]>lim)&&(kk>0)) {
      xflag=0;                                          
      for (int i=1; i<=nvr; i=i+1) {
        ave=0;
        for (int j=1; j<=nvr; j=j+1) {
          ave=ave+q[j][i];
        }
        q[nvx+1][i]=ave/nvr;
      }
      if ((jlof==1)&&(q[nvx+2][0]==q[nvx][0])) {
        jlof=0; cns(g);
      }
      else {
        jlof=0; iv=nvx+2;
        for (int i=1; i<=nvr; i=i+1) {
          q[iv][i]=2*q[nvx+1][i]-q[nvx][i];
        }
        hit(iv, g); q[iv][0]=s;
        if (q[iv][0]>q[nvx][0]) {
          cns(g);
        }
        else {
          if (q[iv][0]<q[1][0]) {
            iv=nvx+3; nexp=2;
            do {
              for (int i=1; i<=nvr; i=i+1) {
                q[iv][i]=(nexp+1)*q[nvx + 1][i]-nexp*q[nvx][i];
              }
              hit(iv, g); q[iv][0]=s;
              if (q[iv][0]<q[iv-1][0]) {
                for (int i=0; i<=nvr; i=i+1) {
                  q[iv-1][i]=q[iv][i];
                }
              }
              else {
                xflag=1;
              }
            } while (xflag==0);
            for (int i=0; i<=nvr; i=i+1) {
              q[nvx][i]=q[nvx+2][i];
            }
          }
          else {
            jlof=1;
            for (int i=0; i<=nvr; i=i+1) {
              q[nvx][i]=q[nvx+2][i];
            }
          }
        }
      }
      sort(g);
    }
    if (kk==3) {
      tx1.setText("a = "+(int)(1000*q[1][1])/1000.);
      tx2.setText("b = "+(int)(1000*q[1][2])/1000.);
      tx3.setText("c = "+(int)(1000*q[1][3])/1000.);
    }
  }

  public void sort(Graphics g) {                       // Sort routine
    double s, temp;
    int x1, y1, x2, y2, x3, y3;
    do {
      s=0;
      for (int i=1; i<=nvr; i=i+1) {
        if (q[i][0]>q[i+1][0]) {
          s=s+1;
          for (int j=0; j<=nvr; j=j+1) {
            temp=q[i][j]; q[i][j]=q[i+1][j]; q[i+1][j]=temp;
          }
        }
      }
    } while (s>0);
    if (kk==2) {
      tx1.setText("phi = "+(-(int)(q[1][1])/100.));
      tx2.setText("tns = "+(int)(100*q[1][2])/100.);
      tx3.setText("dev = "+(int)(100*q[1][0])/100.);
      x1=xs(-q[1][1]/100); y1=ys(q[1][2]);
      x2=xs(-q[2][1]/100); y2=ys(q[2][2]);
      x3=xs(-q[3][1]/100); y3=ys(q[3][2]);
      g.setColor(Color.blue); g.drawLine(x1, y1, x2, y2);
      g.drawLine(x2, y2, x3, y3); g.drawLine(x3, y3, x1, y1);
      g.setColor(Color.red);
    }
  }

  public void cns(Graphics g) {                        // Shrink simplex
    int iv=nvx+2;
    for (int i=1; i<=nvr; i=i+1) {
      q[iv][i] = (q[nvx+1][i]+q[nvx][i])/2;
    }
    hit(iv, g); q[iv][0]=s;
    if (q[iv][0]<q[nvx][0]) {
      for (int i=0; i<=nvr; i=i+1) {
        q[nvx][i]=q[iv][i];
      }
    }
    else {
      for (int i=1; i<=nvr; i=i+1) {
        for (int j=2; j<=nvx; j=j+1) {
          q[j][i]=(q[1][i]+q[j][i]) / 2;
        }
      }
      for (int i=2; i<=nvx; i=i+1) {
        hit(i, g); q[i][0]=s;
      }
    }
  }

  public void actionPerformed(ActionEvent e) {         // Buttons
    String tst;
    tst=e.getActionCommand();
    if (b1s.equals(tst)) {                 
      kk=1; del=10; start();
    }
    if (b2s.equals(tst)) {                 
      kk=2; del=100; start();
    }
    if (b3s.equals(tst)) {                 
      kk=3; del=0; start();
    }
  }
}