Least-squares line fitting: Difference between revisions

Revision as of 19:18, 5 November 2010

@@ Line 1: / Line 1: @@
 <jsxgraph width="600" height="600">
 var brd = JXG.JSXGraph.initBoard('jxgbox',{boundingbox:[-5,5,5,-5], keepaspectratio:true});
-var i, p = [], angle, co, si, delta = 0.8;
+var i, p = [], angle, xr, yr, delta = 0.8;
-// Random points are constructed which lie roughly on a circle
+// Random points are constructed which lie roughly on a line
-// of radius 4 having the origin as center.
+// defined by y = 0.3*x+1.
-// delta*0.5 is the maximal distance in x- and y- direction of the random
+// delta*0.5 is the maximal distance in y-direction of the random
-// points from the circle line.
+// points from the line.
 brd.suspendUpdate();
 for (i=0;i<100;i++) {
-   angle = Math.random()*2*Math.PI;
+   xr = 10*(Math.random()-0.5);
+   yr = xr*0.3+delta*(Math.random()-0.5) +1.0;
-  co = 4*Math.cos(angle)+delta*(Math.random()-0.5);
+   p.push(brd.create('point',[xr, yr], {withLabel:false}));
-   si = 4*Math.sin(angle)+delta*(Math.random()-0.5);
-   p.push(brd.create('point',[co, si], {withLabel:false}));
 }
 brd.unsuspendUpdate();