/* periodic fast Morse 2D     */
/* coded by Ikeuchi Mitsuru   */
/* ver 0.0.1   2003.06.21     */
/* ver 0.0.2   2003.07.03 improved in accuracy */
/* ver 0.0.3   2003.09.22 improved display */
/* ver 0.0.4   2003.11.05 improved more display code */
/* ver 0.0.5   2004.02.03 improved pannel layout */
/* ver 0.0.6   2004.04.12 improved code */
/* ver 0.0.7   2004.06.08 improved velocity verlet code */

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

public class periodicFM2D extends Applet
  implements MouseListener, MouseMotionListener,
    ItemListener, AdjustmentListener, Runnable {

/*-------------------------------------- define gloval -----*/

  Choice cm1,ctc,cvw;
  Scrollbar scr,scs;
  Thread th = null;

  Dimension dim;
  Image imgOff;
  Graphics gOff;

  int sleepTime = 50;
  double sgm = 3.4e-10;       /* L-J sigma for Ar (m)   */
  double dispScale = 10.0/sgm;

  double xMax = 25.0*sgm;      /* x-Box size in (m)      */
  double yMax = 25.0*sgm;      /* y-Box size in (m)      */


  int Nmt = 20*20;             /* number of molecules    */
  int NN = Nmt + 1;
  double t = 0.0;              /* time (s)               */
  double dt = 5.0*1.0e-15;     /* time division (s)      */


  int tempMode = 0;
  double contTemp = 300.0;
  double scale = 1.0;
  int dispMode = 0;

  int dgX, dgY, dgXb, dgYb;
  double xShift = 0.0;
  double yShift = 0.0;

  double rc = 1.0e-9;
  double rc2 = rc*rc;


  double AU = 1.661e-27;
  double EE = 1.602e-19;
  double AA = 1.0e-10;
  double Morse[][] = {
  /*         mass         charge   D(eV)     A(A^-1)    r0(A)   */
  /* 0 W */ {183.85 *AU,  0.0*EE, 0.9906*EE, 1.4116/AA, 3.032*AA},
  /* 1 Mo*/ { 95.94 *AU,  0.0*EE, 0.8032*EE, 1.5079/AA, 2.976*AA},
  /* 2 Cr*/ { 51.996*AU,  0.0*EE, 0.4414*EE, 1.5721/AA, 2.754*AA},
  /* 3 Fe*/ { 55.847*AU,  0.0*EE, 0.4174*EE, 1.3885/AA, 2.845*AA},
  /* 4 Ni*/ { 58.71 *AU,  0.0*EE, 0.4205*EE, 1.4199/AA, 2.780*AA},
  /* 5 Al*/ { 26.98 *AU,  0.0*EE, 0.2703*EE, 1.1646/AA, 3.253*AA},
  /* 6 Pb*/ {207.19 *AU,  0.0*EE, 0.2348*EE, 1.1836/AA, 3.733*AA},
  /* 7 Cu*/ { 63.54 *AU,  0.0*EE, 0.3429*EE, 1.3588/AA, 2.866*AA},
  /* 8 Ag*/ {107.87 *AU,  0.0*EE, 0.3323*EE, 1.3690/AA, 3.115*AA},
  /* 9 Ca*/ { 40.08 *AU,  0.0*EE, 0.1623*EE, 0.8054/AA, 4.569*AA},
  /*10 Sr*/ { 87.62 *AU,  0.0*EE, 0.1513*EE, 0.7878/AA, 4.988*AA},
  /*11 Ba*/ {137.34 *AU,  0.0*EE, 0.1416*EE, 0.6570/AA, 5.373*AA},
  /*12 Na*/ { 22.99 *AU,  0.0*EE, 0.0633*EE, 0.5900/AA, 5.336*AA},
  /*13 K */ { 39.102*AU,  0.0*EE, 0.0542*EE, 0.4977/AA, 6.369*AA},
  /*14 Rb*/ { 85.47 *AU,  0.0*EE, 0.0464*EE, 0.4298/AA, 7.207*AA},
  /*15 Cs*/ {132.905*AU,  0.0*EE, 0.0449*EE, 0.4157/AA, 7.557*AA},
  /*16 Ne*/ { 20.183*AU,  0.0*EE, 0.0031*EE, 1.6500/AA, 3.076*AA},
  /*17 Ar*/ { 39.948*AU,  0.0*EE, 0.0104*EE, 1.3400/AA, 3.816*AA},
  /*18 Kr*/ { 83.80 *AU,  0.0*EE, 0.0141*EE, 1.2500/AA, 4.097*AA},
  /*19 Xe*/ {131.30 *AU,  0.0*EE, 0.0200*EE, 1.2400/AA, 4.467*AA},
  /*20 Hg*/ {200.59 *AU,  0.0*EE, 0.0734*EE, 1.4900/AA, 3.255*AA}
  };
  int NmatKind = 21;

  int MAT0 = 17;
  int MAT1 = 0;
  int MAT2 = 4;
  int MAT3 = 9;
  int MAT4 = 20;
  
  int kind[] = new int[NN];       /* i-th molec 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    */

  int reg[][] = new int[NN][100];   /* registration */

  int kindT[] = new int[NmatKind];
  double forceTable[][][] = new double[5][5][10200];

  double hh = 1.0e-13;

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

  public void init() {
    resize(630,320);
    setBackground(Color.white);

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

    cm1 = new Choice();
    cm1.addItem("W");  cm1.addItem("Mo"); cm1.addItem("Cr");
    cm1.addItem("Fe"); cm1.addItem("Ni"); cm1.addItem("Al");
    cm1.addItem("Pb"); cm1.addItem("Cu"); cm1.addItem("Ag"); 
    cm1.addItem("Ca"); cm1.addItem("Sr"); cm1.addItem("Ba");
    cm1.addItem("Na"); cm1.addItem("K");  cm1.addItem("Rb");
    cm1.addItem("Cs"); cm1.addItem("Ne"); cm1.addItem("Ar");
    cm1.addItem("Kr"); cm1.addItem("Xe"); cm1.addItem("Hg");
    cm1.addItemListener(this);

    ctc = new Choice();
    ctc.addItem("adiabatic"); ctc.addItem("t scaling"); 
    ctc.addItemListener(this);

    cvw = new Choice();
    cvw.addItem("ball"); cvw.addItem("line"); 
    cvw.addItem("both"); cvw.addItem("temp");
    cvw.addItemListener(this);


    scr= new Scrollbar(Scrollbar.HORIZONTAL,30,10,1,210);
    scr.addAdjustmentListener(this);

    scs= new Scrollbar(Scrollbar.HORIZONTAL,100,10,50,210);
    scs.addAdjustmentListener(this);

    addMouseListener(this);  
    addMouseMotionListener(this);

    setLayout(new BorderLayout());
    Panel pnl = new Panel();
    pnl.setLayout(new GridLayout(1,6,5,0));
    pnl.add(cm1);
    pnl.add(ctc);
    pnl.add(cvw);
    pnl.add(new Label("  "));
    pnl.add(scr);
    pnl.add(scs);
    add(pnl,"North");

    setInitialPosition();
  }

  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() == cm1) {
      MAT1 = cm1.getSelectedIndex();
      t = 0.0;
      setInitialPosition();
    } else if (ev.getSource() == ctc) {
      tempMode = ctc.getSelectedIndex();
    } else if (ev.getSource() == cvw) {
      dispMode = cvw.getSelectedIndex();
    }
  }

  public void adjustmentValueChanged(AdjustmentEvent ev){
    if (ev.getSource() == scr) { 
      contTemp = 10.0*(double)(scr.getValue());
      vAjustment();
    } else if (ev.getSource() == scs) { 
      scale = 0.01*(double)(scs.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;
    }
    xShift += (1.0/scale/dispScale)*(dgX-dgXb);
    yShift += (1.0/scale/dispScale)*(dgY-dgYb);
  }

  public void run() {
    while (th != null) {
      try {
        calcposition();
        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,ix,iy,ir,j,k,ix2,iy2;
    int gball,gbx,gby,gb;
    double sc,sz,tmp,tm,r2;

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

    sc = scale*dispScale;
    sz = 0.9*scale*dispScale;
    gbx = 30+(int)(sc*xShift);
    gby = 60+(int)(sc*yShift);
    gball = (int)(5.0*scale);

    tmp = temperature();


    if (dispMode==0) {

      for (i=0; i<Nmt; i++) {
        ix = (int)(sc*xx[i])+gbx;
        iy = (int)(sc*yy[i])+gby;
        ir = (int)(sz*Morse[kind[i]][4] );
        gOff.setColor(Color.getHSBColor((float)(colorOf(i)),0.95f,0.95f));
        gOff.fillOval(ix-ir/2,iy-ir/2, ir, ir);
      }

    } else if (dispMode==1) {

      for (i=0; i<Nmt; i++) {
        ix = (int)(sc*xx[i])+gbx;
        iy = (int)(sc*yy[i])+gby;

        for(k=1;k<reg[i][0];k++) {
          j = reg[i][k];
          r2=(xx[i]-xx[j])*(xx[i]-xx[j])+(yy[i]-yy[j])*(yy[i]-yy[j]);
          if (r2<0.26*(Morse[kind[i]][4]+Morse[kind[j]][4])*(Morse[kind[i]][4]+Morse[kind[j]][4]) && j>i) {
            ix2 = (int)(sc*xx[j])+gbx;
            iy2 = (int)(sc*yy[j])+gby;

            gOff.setColor(Color.gray);
            gOff.drawLine(ix,iy, ix2,iy2);
          }
        }
      }

    } else if (dispMode==2) {

      for (i=0; i<Nmt; i++) {
        ix = (int)(sc*xx[i])+gbx;
        iy = (int)(sc*yy[i])+gby;
        ir = (int)(0.6*sz*Morse[kind[i]][4] );

        for(k=1;k<reg[i][0];k++) {
          j = reg[i][k];
          r2=(xx[i]-xx[j])*(xx[i]-xx[j])+(yy[i]-yy[j])*(yy[i]-yy[j]);
          if (r2<0.26*(Morse[kind[i]][4]+Morse[kind[j]][4])*(Morse[kind[i]][4]+Morse[kind[j]][4]) && j>i) {
            ix2 = (int)(sc*xx[j])+gbx;
            iy2 = (int)(sc*yy[j])+gby;

            gOff.setColor(Color.gray);
            gOff.drawLine(ix,iy, ix2,iy2);
          }
        }
        gOff.setColor(Color.getHSBColor((float)(colorOf(i)),0.95f,0.95f));
        gOff.fillOval(ix-ir/2,iy-ir/2, ir, ir);
      }

    } else if (dispMode==3) {

      for (i=0; i<Nmt; i++) {
        ix = (int)(sc*xx[i])+gbx;
        iy = (int)(sc*yy[i])+gby;
        ir = (int)(sz*Morse[kind[i]][4] );
        tm = 0.5*Morse[kind[i]][0]*(vx[i]*vx[i]+vy[i]*vy[i])/1.38e-23;
        tm = tm/3000.0+0.3;
        if (tm>0.99) {
          tm = 0.99;
        }
        gOff.setColor(Color.getHSBColor((float)(colorOf(i)),0.95f,(float)(tm)));
        gOff.fillOval(ix-ir/2,iy-ir/2, ir, ir);
      }

    }

    gOff.setColor(Color.gray);
    ix = (int)(sc*xMax);
    iy = (int)(sc*yMax);
    gOff.fillRect(gbx-gball,gby-gball,2*gball,iy+2*gball);
    gOff.fillRect(gbx-gball,gby-gball,ix+2*gball,2*gball);
    gOff.fillRect(gbx+ix-gball,gby-gball,2*gball,iy+2*gball);
    gOff.fillRect(gbx-gball,gby+iy-gball,ix+2*gball,2*gball);

    gbx = dim.width/6;
    gOff.setColor(Color.black);
    gOff.drawString("atom",gbx*0+10,40);
    gOff.drawString("temp control",gbx*1+10,40);
    gOff.drawString("view",gbx*2+10,40);
    gOff.drawString("cont T="+contTemp+"K",gbx*4+10,40);
    gOff.drawString("scale="+(int)(scale*100.0+0.499)+"%",gbx*5+10,40);

    gOff.setColor(Color.blue);
    gOff.drawString("t="+(int)(t*1.0e15+0.5)+" fs",gbx*3+10,40);
    gOff.drawString("T="+(int)(tmp*10+0.5)/10.0+" K",gbx*4+10,60);
    gOff.drawString("L="+(int)(xMax*1.0e10+0.5)/10.0+" nm",gbx*5+10,60);

    gb = 630/6*5;
    gOff.setColor(Color.red);
    gOff.drawString("red=Ar",gb,100);
    gOff.setColor(Color.green);
    gOff.drawString("green=Ni",gb,120);
    gOff.setColor(Color.cyan);
    gOff.drawString("cyan=Ca",gb,140);
    gOff.setColor(Color.blue);
    gOff.drawString("blue=Hg",gb,160);
    gOff.setColor(Color.orange);
    gOff.drawString("orange=select",gb,180);
/*
    gOff.setColor(Color.black);
    gOff.drawString("regMax="+regMax()+"",gb,220);
*/
  }

  double colorOf(int i) {
    double col;

    col = 0.0;
    if (kind[i]==MAT0) {
      col = 0.01;
    } else if (kind[i]==MAT1) {
      col = 0.15;
    }  else if (kind[i]==MAT2) {
      col = 0.33;
    }  else if (kind[i]==MAT3) {
      col = 0.50;
    } else if (kind[i]==MAT4) {
      col = 0.66;
    }
    return ( col );
  }

  int regMax() {
    int i,m;

    m = 0;
    for(i=0;i<Nmt;i++) {
      if (reg[i][0]>m) {
        m = reg[i][0];
      }
    }
    return(m);
  }

/*-------------------------------------  statictics  ----------*/


  double rmsV() {
    int i;
    double s;

    s = 0.0; 
    for (i=0; i<Nmt; i++) {
      s += vx[i]*vx[i] + vy[i]*vy[i];
    }
    return ((double)Math.floor(Math.sqrt(s/(double)Nmt)*10.0)/10.0);
  }

  double temperature() {
    int i;
    double s;

    s = 0.0; 
    for (i=0; i<Nmt; i++) {
      s += 0.5*(Morse[kind[i]][0])*(vx[i]*vx[i] + vy[i]*vy[i]);
    }
    return ((double)Math.floor(s/((double)Nmt*1.38e-23)*10.0)/10.0 );
  }

/*-------------------------------------  v ajustment  ---------*/

  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];
    }
  }


/*--------------------------  set forceTable[i][j][ir]   ---------*/

  void setForceTable(){
    int i,j,ir,k0,k1; 
    double d,a,r0,y,r,sc;
    int kkk[] = {MAT0,MAT1,MAT2,MAT3,MAT4};

    kindT[MAT0] = 0; kindT[MAT1] = 1; kindT[MAT2] = 2;
    kindT[MAT3] = 3; kindT[MAT4] = 4;

    for (i=0; i<5; i++) {
      k0=kkk[i];
      for (j=0; j<5; j++) {
        k1=kkk[j];

        d = Math.sqrt(Morse[k0][2]*Morse[k1][2]);
        a = 0.5*(Morse[k0][3]+Morse[k1][3]);
        r0 = 0.5*(Morse[k0][4]+Morse[k1][4]);

        for (ir=100; ir<10000; ir++) {
          r = (double)ir*hh;
          y = Math.exp(-a*(r-r0));
          forceTable[i][j][ir] = cutoff(r)*2.0*d*a*y*(y-1.0);
        }
        for (ir=0; ir<100; ir++) {
          forceTable[i][j][ir]=forceTable[i][j][100];
        }

      }
    }

  }

  double cutoff(double r) {
    double rt;

    rt = 0.0;
    if (r<0.8*rc) {
      rt = 1.0;
    } else if (r>=0.8*rc && r<rc) {
      rt = 0.5+0.5*Math.cos(3.1415926536*(r-0.8*rc)/(0.2*rc));
    } else {
      rt = 0.0;
    }
    return( rt );
  }

/*-----------------------------  set initial position   ---------*/

  void setInitialPosition(){
    int i; 
    double s;

    setForceTable();

    s = 3.4e-10*0.95;
    for (i=0; i<Nmt; i++) {
      if (i%5==0) {
        kind[i] = MAT0;
      } else if (i%5==1) {
        kind[i] = MAT1;
      } else if (i%5==2) {
        kind[i] = MAT2;
      } else if (i%5==3) {
        kind[i] = MAT3;
      } else {
        kind[i] = MAT4;
      }
      xx[i] = s*1.24*(double)(i%20)+0.1*s;
      yy[i] = s*1.24*(double)(i/20)+0.1*s;
      vx[i] = 500.0*Math.random()-250.0;
      vy[i] = 500.0*Math.random()-250.0;
      ffx[i] = 0.0;
      ffy[i] = 0.0;
    }

    vAjustment();
  }

/*-------------------------------  registration   -------------*/

  void registration() {
    int i,j,k;
    double xi,xj,yi,yj;
    double r2,rreg,rreg2;

    rreg = rc + 3000.0*10*dt;
    rreg2 = rreg*rreg;
    for(i=0;i<Nmt;i++) {
      k = 1;
      for(j=i+1;j<Nmt;j++) {
        xi = xx[i]; xj = xx[j]; yi = yy[i]; yj = yy[j];
        if (xi-xj>0.5*xMax) { xj += xMax; };
        if (xi-xj<-0.5*xMax) { xj -= xMax; };  
        if (yi-yj>0.5*yMax) { yj += yMax; };
        if (yi-yj<-0.5*yMax) { yj -= yMax; };
        r2=(xi-xj)*(xi-xj)+(yi-yj)*(yi-yj);
        if (r2<rreg2) {
          reg[i][k]=j;
          k += 1;
        }
      }
      reg[i][0]=k;
    }
  }

/*-------------------------------  molecules motion   ---------*/

  void calcposition(){
    int i;

    if (tempMode==1) {
      vAjustment();
    }

    registration();
    for (i=0; i<10; i++) {
      timeEvolution();
    }
  }

  void timeEvolution(){
    int i; 
    double dtv2, rr, tmp;

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

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

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

  }

  void forceCalc() {
    int i,j,k;
    double xi,xj,yi,yj;
    double r2,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(k=1;k<reg[i][0];k++) {
        j = reg[i][k];
        xi = xx[i]; xj = xx[j]; yi = yy[i]; yj = yy[j];
        if (xi-xj>0.5*xMax) { xj += xMax; };
        if (xi-xj<-0.5*xMax) { xj -= xMax; };  
        if (yi-yj>0.5*yMax) { yj += yMax; };
        if (yi-yj<-0.5*yMax) { yj -= yMax; }; 
        r2=(xi-xj)*(xi-xj)+(yi-yj)*(yi-yj);
        if (r2<rc2) {
          rij = Math.sqrt(r2);
          f = force(rij,kind[i],kind[j]);
          fxij = f*(xi-xj)/rij;
          fyij = f*(yi-yj)/rij;
        } else {
          fxij = 0.0;
          fyij = 0.0;
        }
        ffx[i] +=  fxij;
        ffy[i] +=  fyij;
        ffx[j] += -fxij;
        ffy[j] += -fyij;
      }
    }

  }

  double force(double r, int ki, int kj) {
    int i;
    double a;

    i = (int)(r/hh);
    a = r - i*hh;

    return ( ((hh-a)*forceTable[kindT[ki]][kindT[kj]][i] + 
      a*forceTable[kindT[ki]][kindT[kj]][i+1])/hh );
  }

}  

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