/** applet No. 004
 *
 * load test - tungsten (Morse potential) - molecular dynamics 2D
 *
 * Created by Ikeuchi Mitsuru on June 18 2002.
 * Copyright (c) 2002-2007 Ikeuchi Mitsuru. All rights reserved.
 *
 * ver 0.0.1   2002.06.18  created
 * ver 0.0.2   2002.07.03  version up
 * ver 0.0.3   2007.04.20  improved code
 * ver 0.0.4   2007.05.18  improved code
 * ver 0.0.5   2007.06.26  improved code
 *
 */

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class loadTest extends Applet
  implements ItemListener, ActionListener, AdjustmentListener, Runnable {

  // ------------------------------------ preset field -----------

  Thread th = null; // for run()-paint() thread

  // for event
  Choice ch_tempCont, ch_view;
  Button bt_reset, bt_startStop;
  Scrollbar sc_load, sc_temp;

  // for off-paint buffer
  Dimension dim;
  Image imgOff;
  Graphics gOff;

  // MD2D
  double t = 0.0; // time (s)
  double dt = 5.0*1.0e-15; // time division (s)

  double xMax = 6.0e-9; // x-Box size (m)
  double yMax = 6.0e-9; // y-Box size (m)

  double mas = 183.85*1.661e-27; // mass of W (kg)
  double dMorse = 0.9906*1.6e-19; // Morse potential D for W (J)
  double aMorse = 1.4116*1.0e10; // Morse potential A for W
  double r0Morse = 3.032*1.0e-10; // Morse potential r0 for W (m)

  int tempMode = 2; // 0-adiabatic 1-scaling 2-wall cont
  double contTemp = 300.0; // control temperature (K)
  double atomLoad = 1.0e-9;
  int resetSW = 0;
  int startSW = 1;

  int Nmt = 12*16; // number of molecules
  int NN = Nmt;
  int kind[] = new int[NN]; // i-th kind
  double xx[] = new double[NN]; // i-th x-position
  double yy[] = new double[NN]; // i-th y-position
  double vx[] = new double[NN]; // i-th x-velocity
  double vy[] = new double[NN]; // i-th y-velocity
  double ffx[] = new double[NN]; // i-th x-force
  double ffy[] = new double[NN]; // i-th y-force

  // display
  int sleepTime = 30; // sleep time (ms)
  int dispWidth = 630;
  int dispHeight = 420;

  int dispMode = 0;
  double boxDispWidth = 320.0;
  double dispScale = (boxDispWidth/xMax);
  double viewScale = 1.0;


  // ------------------------------ applet main thread -----------

  public void init() {

    resize(dispWidth,dispHeight);
    setBackground(Color.white);

    dim = getSize();
    imgOff = createImage(dim.width,dim.height);
    gOff = imgOff.getGraphics();

    ch_tempCont = new Choice();
    ch_tempCont.add("adiabatic");
    ch_tempCont.add("T scaling"); 
    ch_tempCont.add("wall cont.");
    ch_tempCont.addItemListener(this);
    ch_tempCont.select("wall cont."); 

    ch_view = new Choice();
    ch_view.add("ball");
    ch_view.add("line");
    ch_view.add("velocity");
    ch_view.addItemListener(this);
    ch_view.select("ball");

    bt_reset= new Button("reset");
    bt_reset.addActionListener(this);

    bt_startStop= new Button("start/stop");
    bt_startStop.addActionListener(this); 

    sc_load = new Scrollbar(Scrollbar.HORIZONTAL,100,10,0,210);
    sc_load.addAdjustmentListener(this);

    sc_temp = new Scrollbar(Scrollbar.HORIZONTAL,300,10,100,1010);
    sc_temp.addAdjustmentListener(this);

    setLayout(new BorderLayout());
    Panel pnl = new Panel();
    pnl.setLayout(new GridLayout(1,6,5,0));
    // pnl.add(new Label("  "));
    pnl.add(bt_reset);
    pnl.add(bt_startStop);
    pnl.add(sc_load);
    pnl.add(ch_tempCont);
    pnl.add(sc_temp);
    pnl.add(ch_view);
    add(pnl,"North");

    setInitialCondition();
  }

  public void start() {
    if (th == null) {
      th = new Thread(this);
      th.start();
    }
  }

  public void stop() {
    if (th != null) th = null;
  }


  // ---------------------------------- event listener -----------

  public void itemStateChanged(ItemEvent ev){
    if (ev.getSource() == ch_tempCont) {
      tempMode = ch_tempCont.getSelectedIndex();
    } else if (ev.getSource() == ch_view) {
      dispMode = ch_view.getSelectedIndex();
    }
  }

  public void actionPerformed(ActionEvent ev){
    if(ev.getSource() == bt_reset){ 
      resetSW = 1;
    } else if (ev.getSource() == bt_startStop){
      if (startSW==0) {
        startSW = 1;
      } else {
        startSW = 0;
      }
    }
  }

  public void adjustmentValueChanged(AdjustmentEvent ev){
    if (ev.getSource() == sc_load) { 
      atomLoad = 0.01*1.0e-9*(double)(sc_load.getValue());
    } else if (ev.getSource() == sc_temp) { 
      contTemp = 1.0*(double)(sc_temp.getValue());
    }
  }



  // ========================= run() - paint() loop ==============

  public void run() {
    while (th != null) {
      timeEvolution();
      offPaint();
      repaint();
      try {
        Thread.sleep(sleepTime);
      } catch (InterruptedException e) { }
    }
  }

  public void update(Graphics g) {
    paint(g);
  }

  public void paint(Graphics g) {
    g.drawImage(imgOff,0,0,this);
  }


  // --------------------------------------- off-paint -----------

  void offPaint() {
    int gbx,gby;
    double sc;

    gOff.setColor(Color.white);
    gOff.fillRect(0,0,dim.width,dim.height);

    gbx = 30;
    gby = 90;
    sc = viewScale*dispScale;

    if (dispMode==0) {
      ballPlot(gbx,gby,sc);

    } else if (dispMode==1) {
      linePlot(gbx,gby,sc);

    } else if (dispMode==2) {
      velocityPlot(gbx,gby,sc, 0.05);

    } else if (dispMode==3) {
      ;

    }

    gOff.setColor(Color.blue);
    gOff.drawString("t="+(int)(t*1.0e13+0.5)/10.0+" ps",10,40);
    gOff.setColor(Color.black);
    if (startSW==0) {
      gOff.drawString("stopped",dispWidth/6*1+10,40);
    } else {
      gOff.drawString("started",dispWidth/6*1+10,40);
    }
    gOff.drawString("load ="+(int)(atomLoad*1.0e11)/100.0+" nN",dispWidth/6*2+10,40);
    gOff.drawString("T cont.",dispWidth/6*3+10,40);
    gOff.drawString("Tc="+contTemp+" K",dispWidth/6*4+10,40);
	
    gOff.setColor(Color.blue);
    gOff.drawString("T="+(int)(temperature()*10+0.5)/10.0+" K",dispWidth/6*4+10,60);

    gOff.setColor(Color.black);
    gOff.drawString("view",dispWidth/6*5+10,40);

    gOff.drawString("Box="+(int)(xMax*1.0e10+0.5)/10.0+" x "+(int)(yMax*1.0e10+0.5)/10.0+" nm",10,60);
  }


  // ------------------------------------ plot methods -----------

  void ballPlot(int gbx, int gby, double sc) {
    int i, ix, iy, ballSize;

    ballSize = (int)(0.9*r0Morse*sc);
    drawBox(gbx, gby, sc, ballSize);

    for (i=0; i<Nmt; i++) {
      ix = (int)(sc*xx[i])+gbx;
      iy = (int)(sc*yy[i])+gby;
      gOff.setColor(Color.blue);
      if (kind[i]==2) {
        gOff.setColor(Color.black);
      }
      gOff.fillOval(ix-ballSize/2,iy-ballSize/2, ballSize, ballSize);
    }
  }

  void linePlot(int gbx, int gby, double sc) {
    int i,ix,iy, j,jx,jy, ballSize;
    double rc2,r2,col;

    rc2 = r0Morse*r0Morse*1.1*1.1;

    ballSize = (int)(0.4*r0Morse*sc);
    drawBox(gbx, gby, sc, ballSize);

    for (i=0; i<Nmt; i++) {
      ix = (int)(sc*xx[i])+gbx;
      iy = (int)(sc*yy[i])+gby;
      for (j=0; j<Nmt; j++) {
        r2 = rsquare(i,j);
        if (r2<=rc2) {
          jx = (int)(sc*xx[j])+gbx;
          jy = (int)(sc*yy[j])+gby;
          col = 0.33-9.0*(Math.sqrt(r2)/r0Morse-1.0);
          if (col<0.01) col = 0.01;
          if (col>0.66) col = 0.66;
          gOff.setColor(Color.getHSBColor((float)col,0.8f,0.8f ));
          gOff.drawLine(ix,iy, jx,jy);
        }
      }
      gOff.setColor(Color.blue);
      if (kind[i]==2) {
        gOff.setColor(Color.black);
      }
      gOff.fillOval(ix-ballSize/2,iy-ballSize/2, ballSize, ballSize);
    }
  }

  double rsquare(int i, int j) {
    double x,y;

    x = xx[i] - xx[j];
    y = yy[i] - yy[j];
    return x*x+y*y;
  }

  void velocityPlot(int gbx, int gby, double sc, double mag) {
    int i, ix, iy, ix2, iy2, ballSize;

    ballSize = (int)(0.9*r0Morse*sc);
    drawBox(gbx, gby, sc, ballSize);

    gOff.setColor(Color.blue);
    for (i=0; i<Nmt; i++) {
      ix = (int)(sc*xx[i])+gbx;
      iy = (int)(sc*yy[i])+gby;
      ix2 = ix+(int)(mag*vx[i]);
      iy2 = iy+(int)(mag*vy[i]);
      gOff.setColor(Color.getHSBColor(0.66f,0.2f,0.9f ));
      gOff.fillOval(ix-ballSize/2,iy-ballSize/2, ballSize, ballSize);
      gOff.setColor(Color.blue);
      gOff.drawLine(ix,iy, ix2, iy2);
    }
  }

  void drawBox(int gbx, int gby, double sc, int ballSize) {
    int ix, iy, gball;
    double tmp;

    gball = ballSize/2;
    tmp = temperature();
    gOff.setColor(Color.gray); 
    if (tempMode==2) {
      gOff.setColor(Color.black); 
      if (tmp<contTemp) { gOff.setColor(Color.red); };
    }
    ix = (int)(sc*xMax);
    iy = (int)(sc*yMax);
    gOff.drawRect(gbx-gball,gby-gball,ix+2*gball,iy+2*gball);
  }



  // ======================== Molecular dymamics 2D ==============

  //  set initial condition

  void setInitialCondition() {
    int i,ix,iy; 
    double a,yd;

    t = 0.0;

    a = 3.032*1.0e-10;
    for (i=0; i<Nmt; i++) {
      ix = i/12;
      iy = i%12;
      yd = 0.0;
      if (ix%2==1) yd = 0.5*a; 

      xx[i] = a*0.5*1.732*((double)ix)+0.1*a;
      yy[i] = a*((double)iy)+yd+1.5e-9;
      vx[i] = 500.0*Math.random()-250.0;
      vy[i] = 500.0*Math.random()-250.0;
      ffx[i] = 0.0;
      ffy[i] = 0.0;
    }
    xx[6*12  ] = xx[11      ]; yy[6*12  ] = yy[11      ]+a;
    xx[6*12+1] = xx[10*12+11]; yy[6*12+1] = yy[10*12+11]+a;
    xx[6*12+2] = xx[12*12+11]; yy[6*12+2] = yy[12*12+11]+a;
    xx[6*12+3] = xx[14*12+11]; yy[6*12+3] = yy[14*12+11]+a;

    for (i=0; i<Nmt; i++) {
      kind[i] = 0;
      if (i<12) {
        kind[i] = 1;
      } else if (i>=12*15) {
        kind[i] = 2;
      }
    }

    vAjustment();
  }


  // ---------------------------------- time evolution -----------

  void timeEvolution() {
    int i;

    if (resetSW==1) {
      setInitialCondition();
      resetSW = 0;
    }

    if (startSW==1) {
      if (tempMode==1) {
        vAjustment();
      }
      for (i=0; i<20; i++) {
        timeStep();
      }
    }
  }

  void timeStep() {
    int i; 
    double dtv2, a;

    dtv2 = dt/2.0;
    t = t + dt;

    for (i=0; i<Nmt; i++) {
      a = dtv2/mas;
      vx[i] += a*ffx[i];
      vy[i] += a*ffy[i];
      xx[i] += vx[i]*dt;
      yy[i] += vy[i]*dt;
    }
    forceCalc();
    for (i=0; i<Nmt; i++) {
      a = dtv2/mas;
      vx[i] += a*ffx[i];
      vy[i] += a*ffy[i];
    }

    setBoundary();
  }

  void forceCalc() {
    int i,j;
    double rij,f,fxij,fyij;

    for(i=0;i<Nmt;i++) {
      ffx[i] = 0.0;
      ffy[i] = 0.0;
    }

    for(i=0;i<Nmt;i++) {
      for(j=i+1;j<Nmt;j++) {
        rij = Math.sqrt((xx[i]-xx[j])*(xx[i]-xx[j])+(yy[i]-yy[j])*(yy[i]-yy[j]));
        f = force(rij);
        fxij = f*(xx[i]-xx[j])/rij;
        fyij = f*(yy[i]-yy[j])/rij;

        ffx[i] += fxij;
        ffy[i] += fyij;

        ffx[j] += -fxij;
        ffy[j] += -fyij;
      }
    }

    for (i=0; i<Nmt; i++) {
      if (kind[i]==1) {
        ffx[i] -= 2.0e-9;
      } else if (kind[i]==2) {
        ffx[i] += atomLoad;
      }
    }

  }

  double force(double r) {
    double y;

    y = Math.exp(-aMorse*(r-r0Morse));
    return ( 2.0*dMorse*aMorse*y*(y-1.0) );
  }

  private void setBoundary() {
    int i; 
    double rr, tmp;

    rr = 1.0;
    if (tempMode==2) {
      tmp = temperature();
      rr = Math.sqrt(contTemp/tmp);
      if (rr<0.5) { rr = 0.5; } else if (rr>1.2) { rr=1.2; };
    }

    for (i=0; i<Nmt; i++) {
      if (xx[i] < 0.0) { 
        xx[i] = 0.0; vx[i] = -rr*vx[i]; vy[i] = rr*vy[i]; 
      }
      if (xx[i] > xMax) {
        xx[i] = xMax; vx[i] = -rr*vx[i]; vy[i] = rr*vy[i]; 
      }
      if (yy[i] < 0.0) { 
        yy[i] = 0.0; vx[i] = rr*vx[i]; vy[i] = -rr*vy[i]; 
      }
      if (yy[i] > yMax) {
        yy[i] = yMax; vx[i] = rr*vx[i]; vy[i] = -rr*vy[i];
      }
    }
  }


  // --------------------------------------- utilities -----------

  double temperature() {
    int i;
    double s;

    s = 0.0; 
    for (i=0; i<Nmt; i++) {
      s += 0.5*mas*(vx[i]*vx[i] + vy[i]*vy[i]);
    }
    return ( s/((double)Nmt*1.38e-23) );
  }

  //

  void vAjustment() {
    int i;
    double tmp, r;

    tmp = temperature();
    r = Math.sqrt(contTemp/tmp);
    for (i=0; i<Nmt; i++) {
      vx[i] = r*vx[i];
      vy[i] = r*vy[i];
    }
  }

}