function d3_layout_forceAccumulate()

in pytheas-core/src/main/resources/js/d3/d3.layout.js [514:545]


function d3_layout_forceAccumulate(quad, alpha, charges) {
  var cx = 0,
      cy = 0;
  quad.charge = 0;
  if (!quad.leaf) {
    var nodes = quad.nodes,
        n = nodes.length,
        i = -1,
        c;
    while (++i < n) {
      c = nodes[i];
      if (c == null) continue;
      d3_layout_forceAccumulate(c, alpha, charges);
      quad.charge += c.charge;
      cx += c.charge * c.cx;
      cy += c.charge * c.cy;
    }
  }
  if (quad.point) {
    // jitter internal nodes that are coincident
    if (!quad.leaf) {
      quad.point.x += Math.random() - .5;
      quad.point.y += Math.random() - .5;
    }
    var k = alpha * charges[quad.point.index];
    quad.charge += quad.pointCharge = k;
    cx += k * quad.point.x;
    cy += k * quad.point.y;
  }
  quad.cx = cx / quad.charge;
  quad.cy = cy / quad.charge;
}