th_canvas") {
		if(points.length > 0) {
			var polynomial = approximation_with_autoweighted_interpolating_n(points, both_degree + 1, ips);

			context.beginPath();
			for(var j = 1; j < w; ++j){
				x = j;
				y = polynomial(x);
				if(j == 0)
					context.moveTo(x, y);
				else
					context.lineTo(x, y);
			}
			context.strokeStyle="#62d645";
			context.stroke();
			context.closePath();
		}
	}

	context.lineWidth = 1;

	// points
	for (var i = 0; i < points.length; ++i) {
		if(canvas_name == "approximation