Difference between revisions of "Differential equations"

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Line 3: Line 3:
 
var P = brd.create('point',[0,0], {name:'x_0'});
 
var P = brd.create('point',[0,0], {name:'x_0'});
 
var f = function(t,x) {
 
var f = function(t,x) {
       return 3*x;
+
       return [3*x[0]];
 
     };
 
     };
  
 
function ode() {
 
function ode() {
  var I = [0, 25];
+
   var data = JXG.Math.Numerics.rungeKutta(JXG.Math.Numerics.predefinedButcher.Heun, [1], [0, 2], 20, f);
  var N = 1000;
+
}
  var x0 = P.Y();
 
   var data = JXG.Math.Numerics.rungeKutta(JXG.Math.Numerics.predefinedButcher.Euler, x0, I, N, f);
 
  var t = [];
 
  var q = I[0];
 
  var h = (I[1]-I[0])/N;
 
  for(var i=0; i<data.length; i++) {
 
      data[i].push(q);
 
      q += h;
 
  }
 
  return data;
 
};
 
  
 
var g = brd.createElement('curve', [[0],[0]], {strokeColor:'red', strokeWidth:'2px'});
 
var g = brd.createElement('curve', [[0],[0]], {strokeColor:'red', strokeWidth:'2px'});
 
g.updateDataArray = function() {
 
g.updateDataArray = function() {
 
     var data = ode();
 
     var data = ode();
 +
    var h = 0.1;
 
     this.dataX = [];
 
     this.dataX = [];
 
     this.dataY = [];
 
     this.dataY = [];
 
     for(var i=0; i<data.length; i++) {
 
     for(var i=0; i<data.length; i++) {
         this.dataX[i] = data[i][2];
+
         this.dataX[i] = i*h;
 
         this.dataY[i] = data[i][0];
 
         this.dataY[i] = data[i][0];
 
     }
 
     }

Revision as of 11:30, 14 July 2010

The underlying JavaScript code