new histograph values
	const nhist = histogram(data, nbarwidth, min, max);

	const rects = container
	      .selectAll(".bar")
   	      .data(nhist);

	rects.exit().remove();

	rects.enter().append("rect").attr("class", "bar")
	    .merge(rects)
	    .attr("x", (v, i) => xscale(i*nbarwidth+min))
	    .attr("width", (v, i) => xscale(nbarwidth)-xscale(0))
	    .attr("y", (v, i) => yscale(v))
	    .attr("height", (v, i) => innerH-yscale(v))
	    .on("mouseover", print_value)
            .on("mouseout", () => 