Молекулярная динамика — различия между версиями

  1 <br />
  2     window.addEventListener('load',main,false)
  3     function main(){
  4     var N = document.getElementById("num").value;
  5     Num = document.getElementById("num").value;
  6     my = document.getElementById("my");
  7     my.innerHTML =Num + " частиц";
  8     var animation = 0;
  9     var za = 0;
 10     var ctx2 = canvasex2.getContext('2d');
 11     var cplot = canvasex1.getContext('2d');
 12     var cpl = canvasex3.getContext('2d');
 13     var w = canvasex1.width;
 14     var h = canvasex1.height;
 15     var particles = [];
 16     var t_max = 0;
 17     var E=[];
 18     var Ep=[];
 19     una.onclick= function una(){
 20     animation = 0;
 21     }
 22     start.onclick= function start(){
 23     var D = document.getElementById("D").value;  //энергия связи
 24     var beta = document.getElementById("b").value;  //вязкость
 25     animation=1;
 26     za += 1;
 27     var l = canvasex2.height;
 28     var a = 30; //равновесное расстояние
 29     var m = 1;
 30     var rad = 10;
 31     var dt=1/60;
 32 	
 33     function Particle(x,y,vx,vy){
 34     var that=this;
 35     this.x=x;
 36     this.y=y;
 37     this.vx=vx;
 38     this.vy=vy;
 39     this.info = function (){
 40     console.log('Position: ('+that.x+','+that.y+')\nVelocity: ('+that.vx+','+that.vy+')')
 41     }	
 42     this.move=function(){
 43     if ((that.x-rad)<0||(that.x+rad)>l){
 44     that.vx*=-1;
 45     }
 46     if ((that.y-rad)<0||(that.y+rad)>l){
 47     that.vy*=-1;
 48     }
 49     that.x+=that.vx*dt;
 50     that.y+=that.vy*dt;
 51     }		
 52     this.draw = function(){
 53     ctx2.beginPath();
 54     ctx2.arc(that.x,that.y,rad,0,2*Math.PI);
 55     ctx2.fillStyle = '#9999FF';
 56     ctx2.fill();
 57     }
 58     }
 59 	
 60     if (za==1){	// создание частиц
 61     for(var i=0;i<N;i++){
 62     var fi= Math.random()*2*Math.PI;
 63     particles.push(
 64     new Particle(
 65        50+Math.random()*400,
 66        50+Math.random()*400,
 67        20*Math.cos(fi),
 68        20*Math.sin(fi),
 69         )
 70         );	
 71     if (i!=0){
 72       for (var z = 1;i-z>=0;z++)
 73         {
 74           if (Math.sqrt((particles[i].x-particles[i-z].x)*(particles[i].x-particles[i-z].x)+(particles[i].y-particles[i-z].y)*(particles[i].y-particles[i-z].y))<a)
 75              { particles.length = particles.length-1;
 76                     i = i-1;
 77              }
 78          }
 79         }
 80        particles[i].draw();		
 81       }
 82      }
 83 
 84      function phys(){
 85         var ep = 0;
 86        for(var i=0;i<N;i++){
 87           particles[i].move();
 88           for(var j=0;j<N;j++){;
 89              if(i!=j){
 90                  var F = 0;
 91                  var rx = particles[j].x-particles[i].x;
 92                  var ry = particles[j].y-particles[i].y;
 93                  var r = Math.sqrt(Math.pow(rx,2)+Math.pow(ry,2));
 94                  var K = Math.pow(1-Math.pow((r*r-1.21*a*a)/(16-1.21)/a/a,2),2);
 95                  if (r<1.1*a){   K = 1;   }
 96                  if (r>4*a){     K = 0;   }
 97                  if (r<15){   r = 15;   }
 98                  F = K*(12*D/a)*(Math.pow((a/r),13)-Math.pow((a/r),7));
 99                  ep+=D*(Math.pow((a/r),12)-2*Math.pow((a/r),6));
100                  particles[i].vx = (particles[i].vx*Math.exp(-beta*dt) - (rx/r)*F*dt/m);
101                  particles[i].vy = (particles[i].vy*Math.exp(-beta*dt) - (ry/r)*F*dt/m);
102                    }
103                 }
104              }
105          for (var i=0;i<N;i++){
106               particles[i].x = particles[i].x+particles[i].vx*dt;
107               particles[i].y = particles[i].y+particles[i].vy*dt;
108             }
109          Ep.push(ep);
110          var e = 0;
111          for (var ii=0;ii<N;ii++){
112               e+=(particles[ii].vx*particles[ii].vx+particles[ii].vy*particles[ii].vy)/2;
113             }
114         E.push(e);
115         t_max+=dt;
116       }
117 	
118     function draw(){
119         ctx2.clearRect(0,0,500,500);
120         for(var i=0;i<N;i++){
121         particles[i].draw();}
122         var Ep_scale =(h-20)/Math.max.apply(null,Ep);
123         var E_scale =(h-20)/Math.max.apply(null,E);
124         var t_scale= w/t_max;
125         cplot.beginPath();
126         cpl.beginPath();
127         for (var i =0; i<E.length-1; i++){
128             cplot.clearRect(0,0,w,h);
129             cpl.clearRect(0,0,w,h);	
130             cplot.moveTo(dt*i*t_scale,3*h/4-Ep[i]*(Ep_scale));
131             cplot.lineTo(dt*(i+1)*t_scale, 3*h/4-Ep[i+1]*(Ep_scale));
132             cplot.font = "28px calibri";
133             cplot.strokeText("Ep="+Ep[i].toFixed(1),20,280)	
134             cpl.moveTo(dt*i*t_scale,h-E[i]*(E_scale));
135             cpl.lineTo(dt*(i+1)*t_scale, h-E[i+1]*(E_scale));
136             cpl.font = "28px calibri";
137             cpl.strokeText("Ek="+E[i].toFixed(1),20,280)
138             cplot.stroke();
139             cpl.stroke();						
140             }
141         }
142 	
143     function control(){
144         if (animation!=0){
145             phys();
146             draw();
147           }
148         }
149     setInterval(control,1000*dt);
150     }
151    }