/* ion scatter QED2D         */
/* coded by Ikeuchi Mitsuru  */
/* ver 0.0.1   2004.04.25    */

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

public class ionScatterQED2D extends Applet
  implements MouseListener, MouseMotionListener,
    ItemListener, ActionListener, AdjustmentListener, Runnable {

/* -------------------------------------- set global ------ */

  Choice cvw;
  Button bt_reset, bt_start, bt_stop;
  Scrollbar spx,spy;
  Thread th = null;

  Dimension dim;
  Image imgOff;
  Graphics gOff;

  int sleepTime = 30;

  int dispMode = 1;
  int started = 1;

  double px0 = 4.0;
  double py0 = 0.0;


  int dgX, dgY, dgXb,dgYb;
  double viewTheta = -15.0*3.14/180.0;
  double viewFai = -72.0*3.14/180.0;
  double dtheta = 0.0*3.14/180.0;
  double pai = 3.1415926536;

  double cosTh = Math.cos(viewTheta); 
  double sinTh = Math.sin(viewTheta);
  double cosFi = Math.cos(viewFai);
  double sinFi = Math.sin(viewFai);


  double t = 0.0;

  double dx = 1.0/32.0;
  double dy = 1.0/32.0;

  double dt = 8.0*dx*dx;

  int NNx = 512+1;
  int NNy = 512+1;
  int NN = NNx+1; /* max(NNx,NNy)+1 */

  double phRe[][] = new double[NNx][NNy];
  double phIm[][] = new double[NNx][NNy];  

  double vv[][] = new double[NNx][NNy];

  double aaRe[] = new double[NN];
  double aaIm[] = new double[NN];
  double bbRe[] = new double[NN];
  double bbIm[] = new double[NN];
  double bRe[] = new double[NN];
  double bIm[] = new double[NN];
  double uRe[] = new double[NN];
  double uIm[] = new double[NN];

  int xpts[] = new int[NN];
  int ypts[] = new int[NN];
  double icol[] = new double[NN];

/* ----------------------------- applet control ------ */

  public void init() {

    resize(630,320);
    setBackground(Color.white);

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

    cvw = new Choice();
    cvw.addItem("density"); cvw.addItem("grid"); 
    cvw.addItemListener(this);
    cvw.select("grid");

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

    bt_start= new Button("start");
    bt_start.addActionListener(this); 

    bt_stop = new Button("stop");
    bt_stop.addActionListener(this);
    
    spx= new Scrollbar(Scrollbar.HORIZONTAL,80,10,0,210);
    spx.addAdjustmentListener(this);

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

    addMouseListener(this);  
    addMouseMotionListener(this);

    setLayout(new BorderLayout());
    Panel pnl = new Panel();
    pnl.setLayout(new GridLayout(1,6,5,0));
    pnl.add(bt_reset);
    pnl.add(bt_start);
    pnl.add(bt_stop);
    pnl.add(cvw);
    pnl.add(spx);
    pnl.add(spy);
    add(pnl,"North");

    setInitialCondition();
  }

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

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

  public void itemStateChanged(ItemEvent ev){
    if (ev.getSource() == cvw){
      dispMode = cvw.getSelectedIndex();
    }
  }

  public void actionPerformed(ActionEvent ev){
    if(ev.getSource() == bt_reset){ 
      t = 0.0;
      setInitialCondition();
      started = 0;
    } else if(ev.getSource() == bt_start){ 
      started = 1;
    } else if(ev.getSource() == bt_stop){
      started = 0;
    }
		}

  public void adjustmentValueChanged(AdjustmentEvent ev){
    if (ev.getSource() == spx) { 
      px0 = 0.1*(double)(spx.getValue());
    } else if (ev.getSource() == spy) { 
      py0 = 0.1*(double)(spy.getValue());
    }
  }

  public void mousePressed(MouseEvent ev){ }
  public void mouseReleased(MouseEvent ev){
    dgXb = 0; dgYb = 0;
    dgX = 0; dgY = 0;
  }
  public void mouseClicked(MouseEvent ev){ }
  public void mouseEntered(MouseEvent ev){ } 
  public void mouseExited (MouseEvent ev){ }

  public void mouseMoved  (MouseEvent ev){ }

  public void mouseDragged(MouseEvent ev){
    dgXb = dgX; dgYb = dgY;
    dgX=ev.getX();
    dgY=ev.getY();
    if (dgXb==0 && dgYb==0) {
      dgXb = dgX; dgYb = dgY;
    }
    viewTheta += 0.5*3.14/180.0*(dgX-dgXb);
    viewFai += 0.5*3.14/180.0*(dgY-dgYb);
    cosTh = Math.cos(viewTheta); 
    sinTh = Math.sin(viewTheta);
    cosFi = Math.cos(viewFai);
    sinFi = Math.sin(viewFai);
  }

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

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

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

/* ----------------------------- offPaint -------------------- */

  void offPaint() {
    int i,j,gbx,gby,mag;
    int cx,cy,cz;
    double z,px,py,pz,sc;
    double v1,v2,ph2;

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


    if (dispMode==0) {

      gbx = 30;
      gby = 60;
      mag = 2;

      gOff.setColor(Color.black);
      gOff.fillRect(gbx-1,gby-1,(NNx+1)/mag,(NNy+1)/mag);

      for (i=1; i<NNx-1; i+=mag) {
	    for (j=1; j<NNy-1; j+=mag) {
          ph2 = 2.0*(phRe[i][j]*phRe[i][j]+phIm[i][j]*phIm[i][j])+0.0004*vv[i][j];
          if (ph2>0.9) {
            ph2 = 0.9;
          }
          if (ph2>=0.01) {
            gOff.setColor(Color.getHSBColor(
              (float)(0.15+0.0004*vv[i][j]), 0.95f, (float)(ph2+0.1)));
            gOff.fillRect(gbx+i/mag,gby+j/mag, 1, 1);
          }
        }
      }

    } else if (dispMode==1) {

      cx = NNx/2;
      cy = NNy/2;
      cz = 0;
      sc = 1.0;

      gbx = -200+(int)(cx/sc);
      gby = -300+(int)(cy/sc);
      for(j=0; j<NNy; j += 8) {
        for (i=0; i<NNx; i++) { 
          ph2 = phRe[i][j]*phRe[i][j]+phIm[i][j]*phIm[i][j];
          z = 100.0*ph2 + 0.5*vv[i][j] + cz;
          py = cosFi*(j-cy)+sinFi*(z-cz) + cy; 
          pz = -sinFi*(j-cy)+cosFi*(z-cz) + cz;
          px = cosTh*(i-cx)+sinTh*(pz-cz) + cx; 
          pz = -sinTh*(i-cx)+cosTh*(pz-cz) + cz;
          xpts[i] = (int)(sc*px)+gbx;
          ypts[i] = (int)(sc*py)+gby;
          if (ph2>0.02) {
            icol[i] = 0.15;
          } else if (vv[i][j]>0.0) {
            icol[i] = 0.33+0.001*vv[i][j];
          } else {
            icol[i] = 0.66;
          }
        }
        for (i=0; i<NNx-2; i++) {
          gOff.setColor(Color.getHSBColor((float)icol[i],0.9f,0.8f));
          gOff.drawLine(xpts[i],ypts[i],xpts[i+1],ypts[i+1]);
        }
      }

      for(i=0; i<NNx; i += 8) {
        for (j=0; j<NNy; j++) {
          ph2 = phRe[i][j]*phRe[i][j]+phIm[i][j]*phIm[i][j];
          z = 100.0*ph2 + 0.5*vv[i][j] + cz;
          py = cosFi*(j-cy)+sinFi*(z-cz) + cy; 
          pz = -sinFi*(j-cy)+cosFi*(z-cz) + cz;
          px = cosTh*(i-cx)+sinTh*(pz-cz) + cx; 
          pz = -sinTh*(i-cx)+cosTh*(pz-cz) + cz;
          xpts[j] = (int)(sc*px)+gbx;
          ypts[j] = (int)(sc*py)+gby;
          if (ph2>0.02) {
            icol[j] = 0.15;
          } else if (vv[i][j]>0.0) {
            icol[j] = 0.33;
          } else {
            icol[j] = 0.66;
          }
        }
        for (j=0; j<NNy-2; j++) { 
          gOff.setColor(Color.getHSBColor((float)icol[j],0.9f,0.8f));
          gOff.drawLine(xpts[j],ypts[j],xpts[j+1],ypts[j+1]);
        }
      }

    } else if (dispMode==2) {


    }


    gOff.setColor(Color.black);
    gOff.drawString("view",630/6*3+10,40);
    gOff.drawString("px0="+(int)(px0*10.0+0.5)/10.0+" au",630/6*4+10,40);
    gOff.drawString("py0="+(int)(py0*10.0+0.5)/10.0+" au",630/6*5+10,40);
    gOff.drawString("vx0="+(int)(px0*2.79+0.5)/10.0+" %c",630/6*4+10,60);
    gOff.drawString("vy0="+(int)(py0*2.79+0.5)/10.0+" %c",630/6*5+10,60);

    gOff.drawString("Lx="+(int)(NNx*dx*52.918+0.5)+" pm",630/6*4+10,80);
    gOff.drawString("Ly="+(int)(NNy*dy*52.918+0.5)+" pm",630/6*5+10,80);

    gOff.setColor(Color.blue);
    gOff.drawString("t="+(int)(t*2418.9+0.5)/100.0+" as",10,40);
    gOff.drawString("norm="+norm()+" ",630/6*1+10,40);

  }
/*-------------------------- statistics ----------*/

  double norm() {
    int i,j;
    double p;

    p = 0.0;
    for (i=0; i<NNx; i++) {
      for (j=0; j<NNy; j++) {
        p += (phRe[i][j]*phRe[i][j]+phIm[i][j]*phIm[i][j])*dx*dy;
      }
    }
    return ( p );
  }

/*-------------------------- set initial condition ----------*/

  void setInitialCondition() {
    t = 0.0;
    setWave(3.0,5.0, 0.5, px0, py0);
    setPotential();

  }

/* ----------------------------- set potential -------------- */

  void setPotential() {
    int i,j;
    double x0,y0;
    double x,y,r,s,v;

    x0 = 8.0;
    y0 = 8.0;

    for (i=1;i<NNx-1;i++) {
      for (j=1;j<NNy-1;j++) {
        x = i*dx;
        y = j*dy;
        r = Math.sqrt((x-x0)*(x-x0)+(y-y0)*(y-y0));
        s = 1.0/(r+0.0001);
        v = 70.0*(s*s*s*s*s*s*s*s-s)+20.0;
        if (v>50.0) {
		  v = 50.0;
        }
        vv[i][j] = v;
      }
    }
  }

/* ----------------------------- set wave packet -------------- */

  void setWave(double xPos, double yPos, double waveWidth, double kx, double ky) {
    int i,j;
    double a,x,y,phAb,phPh;

    for (i=1;i<NNx-1;i++) {
      for (j=1;j<NNy-1;j++) {
        x = i*dx;
        y = j*dy;
        phAb = Math.exp(-((x-xPos)*(x-xPos)+(y-yPos)*(y-yPos))/(4.0*waveWidth*waveWidth) );
        phPh = kx*x+ky*y;
        phRe[i][j] = phAb*Math.cos(phPh);
        phIm[i][j] = phAb*Math.sin(phPh);
      }
    }
    for (i=1;i<NNx-1;i++) {
      phRe[i][0] = 0.0;
      phIm[i][0] = 0.0;
      phRe[i][NNy-1] = 0.0;
      phIm[i][NNy-1] = 0.0;
    }
    for (j=1;j<NNy-1;j++) {
      phRe[0][j] = 0.0;
      phIm[0][j] = 0.0;
      phRe[NNx-1][j] = 0.0;
      phIm[NNx-1][j] = 0.0;
    }

    a = Math.sqrt(norm());
	
    for (i=1;i<NNx-1;i++) {
      for (j=1;j<NNy-1;j++) {
        phRe[i][j] = phRe[i][j]/a;
        phIm[i][j] = phIm[i][j]/a;
      }
    }
  }

/* ----------------------------- timeEvolution -------------- */

  void timeEvolution() {
    int i;

    if (started==1) {
      for (i=0; i<2; i++) {
        t = t + dt;
        phaseStep();
        kxStep();
        kyStep();
        phaseStep();
      }
    }
  }

/* ----------------------------- time step -------------- */

  void kxStep() {
    int i,j;
    double aaAb,auAb;

    for (j=1; j<NNy-1; j++) {
      for (i=1; i<NNx-1; i++) {
        bbRe[i] = 2.0;
        bbIm[i] = 4*dx*dx/dt;
        aaRe[i] = -2.0;
        aaIm[i] = 4*dx*dx/dt;
        bRe[i] = bbRe[i]*phRe[i][j]-bbIm[i]*phIm[i][j]-phRe[i+1][j]-phRe[i-1][j];
        bIm[i] = bbRe[i]*phIm[i][j]+bbIm[i]*phRe[i][j]-phIm[i+1][j]-phIm[i-1][j];
      }

      aaAb = aaRe[1]*aaRe[1]+aaIm[1]*aaIm[1];
      uRe[1] = aaRe[1]/aaAb;
      uIm[1] = -aaIm[1]/aaAb;
      phRe[1][j] = bRe[1]*uRe[1] - bIm[1]*uIm[1];
      phIm[1][j] = bIm[1]*uRe[1] + bRe[1]*uIm[1];
      for (i=2; i<NNx-1; i++) {
        auAb = (aaRe[i]-uRe[i-1])*(aaRe[i]-uRe[i-1])+(aaIm[i]-uIm[i-1])*(aaIm[i]-uIm[i-1]);
        uRe[i] = (aaRe[i]-uRe[i-1])/auAb;
        uIm[i] = -(aaIm[i]-uIm[i-1])/auAb;
        phRe[i][j] = (bRe[i]-phRe[i-1][j])*uRe[i] - (bIm[i]-phIm[i-1][j])*uIm[i];
        phIm[i][j] = (bRe[i]-phRe[i-1][j])*uIm[i] + (bIm[i]-phIm[i-1][j])*uRe[i];
      }

      for (i=NNx-3; i>=1; i--) {
        phRe[i][j] -= phRe[i+1][j]*uRe[i] - phIm[i+1][j]*uIm[i];
        phIm[i][j] -= phRe[i+1][j]*uIm[i] + phIm[i+1][j]*uRe[i];
      }
    }
  }

  void kyStep() {
    int i,j;
    double aaAb,auAb;

    for (i=1; i<NNx-1; i++) {
      for (j=1; j<NNy-1; j++) {
        bbRe[j] = 2.0;
        bbIm[j] = 4*dy*dy/dt;
        aaRe[j] = -2.0;
        aaIm[j] = 4*dy*dy/dt;
        bRe[j] = bbRe[j]*phRe[i][j]-bbIm[j]*phIm[i][j]-phRe[i][j+1]-phRe[i][j-1];
        bIm[j] = bbRe[j]*phIm[i][j]+bbIm[j]*phRe[i][j]-phIm[i][j+1]-phIm[i][j-1];
      }

      aaAb = aaRe[1]*aaRe[1]+aaIm[1]*aaIm[1];
      uRe[1] = aaRe[1]/aaAb;
      uIm[1] = -aaIm[1]/aaAb;
      phRe[i][1] = bRe[1]*uRe[1] - bIm[1]*uIm[1];
      phIm[i][1] = bIm[1]*uRe[1] + bRe[1]*uIm[1];
      for (j=2; j<NNy-1; j++) {
        auAb = (aaRe[j]-uRe[j-1])*(aaRe[j]-uRe[j-1])+(aaIm[j]-uIm[j-1])*(aaIm[j]-uIm[j-1]);
        uRe[j] = (aaRe[j]-uRe[j-1])/auAb;
        uIm[j] = -(aaIm[j]-uIm[j-1])/auAb;
        phRe[i][j] = (bRe[j]-phRe[i][j-1])*uRe[j] - (bIm[j]-phIm[i][j-1])*uIm[j];
        phIm[i][j] = (bRe[j]-phRe[i][j-1])*uIm[j] + (bIm[j]-phIm[i][j-1])*uRe[j];
      }

      for (j=NNy-3; j>=1; j--) {
        phRe[i][j] -= phRe[i][j+1]*uRe[j] - phIm[i][j+1]*uIm[j];
        phIm[i][j] -= phRe[i][j+1]*uIm[j] + phIm[i][j+1]*uRe[j];
      }
    }
  }

  void phaseStep() {
    int i,j;
    double th,cs,sn,phr,phi;

    for (i=1; i<NNx-1; i++) {
      for (j=1; j<NNy-1; j++) {
        th = 0.5*dt*vv[i][j];
        cs = Math.cos(th); sn = Math.sin(th);
        phr = phRe[i][j];
        phi = phIm[i][j];
        phRe[i][j] = cs*phr+sn*phi;
        phIm[i][j] = cs*phi-sn*phr;
      }
    }
  }

/* ----------------------------- end of applet -------------- */

}