d3.layout.partition = function() {

  var hierarchy = d3.layout.hierarchy(),

      size = [1, 1]; // width, height

  function position(node, x, dx, dy) {

    var children = node.children;

    node.x = x;

    node.y = node.depth * dy;

    node.dx = dx;

    node.dy = dy;

    if (children && (n = children.length)) {

      var i = -1,

          n,

          c,

          d;

      dx = node.value ? dx / node.value : 0;

      while (++i < n) {

        position(c = children[i], x, d = c.value * dx, dy);

        x += d;

      }

    }

  }

  function depth(node) {

    var children = node.children,

        d = 0;

    if (children && (n = children.length)) {

      var i = -1,

          n;

      while (++i < n) d = Math.max(d, depth(children[i]));

    }

    return 1 + d;

  }

  function partition(d, i) {

    var nodes = hierarchy.call(this, d, i);

    position(nodes[0], 0, size[0], size[1] / depth(nodes[0]));

    return nodes;

  }

  partition.size = function(x) {

    if (!arguments.length) return size;

    size = x;

    return partition;

  };

  return d3_layout_hierarchyRebind(partition, hierarchy);

};