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@KKostya
Created July 17, 2013 14:18
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Animated Joukowski map
<!DOCTYPE html>
<meta charset="utf-8">
<style>
.ani .line { fill: none; stroke: steelblue; stroke-width: 1.5px; }
.grd .line { fill: none; stroke: black; stroke-width: 0.5px; }
</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
function Complex(re, im) { this.re = re; this.im = im; };
Complex.prototype.clone = function(){ return new Complex(this.re,this.im); };
Complex.prototype.add = function(z) { this.re += z.re; this.im += z.im; return this; };
Complex.prototype.sub = function(z) { this.re -= z.re; this.im -= z.im; return this; };
Complex.prototype.mul = function(z)
{
var tmp = this.re;
this.re = this.re*z.re - this.im*z.im;
this.im = tmp*z.im + this.im*z.re;
return this;
};
Complex.prototype.div = function(z)
{
var tmp = this.re,
n = z.re*z.re + z.im*z.im;
this.re = (this.re*z.re + this.im*z.im)/n;
this.im = ( -tmp*z.im + this.im*z.re)/n;
return this;
};
var width = 960, height = 500;
var svg = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height", height);
var grd = svg.append("g").attr("class","grd");
var ani = svg.append("g").attr("class","ani");
var x = d3.scale.linear()
.range( [ 0, width])
.domain([ -5, 5]);
var y = d3.scale.linear()
.range( [height, 0])
.domain([ -5, 5]);
var line = d3.svg.line()
.x(function(d) { return x(d.re); })
.y(function(d) { return y(d.im); });
function ProduceData(roff,poff)
{
var data = d3.range(0.87+roff,roff,-0.02).map(function(r){
return d3.range(-Math.PI/4+poff,7*Math.PI/4,Math.PI/50).map(function(p){
return new Complex(r*Math.cos(p)-0.2,r*Math.sin(p)+0.2);})})
data.forEach(function(d){d.forEach(function(z) {z.add((new Complex(1,0)).div(z));})});
return data;
}
var data = ProduceData(0,0.01);
var save = data[0];
data = d3.transpose(data);
save.push(save[0]);
data.unshift(save);
var paths = grd.selectAll('path').data(data);
paths.enter().append('path').attr('class','line');
paths.attr('d',line)
function plot(offset)
{
var data = ProduceData(offset,0);
var paths = ani.selectAll('path').data(data);
paths.enter().append('path').attr('class','line');
paths.attr('d',function(d) { return line(d) + 'Z'; })
.attr('stroke-opacity', function(d,i){ if(i<20) return i/20; else return 1.; });
paths.exit().remove();
}
var off = 0;
d3.timer(function() { plot(off); off -= 0.001; if(off<0) off=0.019;});
</script>
</body>
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