diff --git a/js/labeler.js b/js/labeler.js
new file mode 100644
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--- /dev/null
+++ b/js/labeler.js
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+(function() {
+
+d3.labeler = function() {
+  var lab = [],
+      anc = [],
+      w = 1, // box width
+      h = 1, // box width
+      update,
+      labeler = {};
+
+  var max_move = 5.0/20,
+      max_angle = 0.5,
+      acc = 0;
+      rej = 0;
+
+  // weights
+  var w_len = 0.2, // leader line length 
+      w_inter = 1.0, // leader line intersection
+      w_lab2 = 30.0, // label-label overlap
+      w_lab_anc = 30.0; // label-anchor overlap
+      w_orient = 3.0; // orientation bias
+
+  // booleans for user defined functions
+  var user_energy = false,
+      user_schedule = false;
+
+  var user_defined_energy, 
+      user_defined_schedule;
+
+  energy = function(index) {
+  // energy function, tailored for label placement
+
+      var m = lab.length, 
+          ener = 0,
+          dx = lab[index].x - anc[index].x,
+          dy = anc[index].y - lab[index].y,
+          dist = Math.sqrt(dx * dx + dy * dy),
+          overlap = true,
+          amount = 0
+          theta = 0;
+
+      // penalty for length of leader line
+      if (dist > 0) ener += dist * w_len;
+
+      // label orientation bias
+      dx /= dist;
+      dy /= dist;
+      if (dx > 0 && dy > 0) { ener += 0 * w_orient; }
+      else if (dx < 0 && dy > 0) { ener += 1 * w_orient; }
+      else if (dx < 0 && dy < 0) { ener += 2 * w_orient; }
+      else { ener += 3 * w_orient; }
+
+      var x21 = lab[index].x,
+          y21 = lab[index].y - lab[index].height + 2.0,
+          x22 = lab[index].x + lab[index].width,
+          y22 = lab[index].y + 2.0;
+      var x11, x12, y11, y12, x_overlap, y_overlap, overlap_area;
+
+      for (var i = 0; i < m; i++) {
+        if (i != index) {
+
+          // penalty for intersection of leader lines
+          overlap = intersect(anc[index].x, lab[index].x, anc[i].x, lab[i].x,
+                          anc[index].y, lab[index].y, anc[i].y, lab[i].y);
+          if (overlap) ener += w_inter;
+
+          // penalty for label-label overlap
+          x11 = lab[i].x;
+          y11 = lab[i].y - lab[i].height + 2.0;
+          x12 = lab[i].x + lab[i].width;
+          y12 = lab[i].y + 2.0;
+          x_overlap = Math.max(0, Math.min(x12,x22) - Math.max(x11,x21));
+          y_overlap = Math.max(0, Math.min(y12,y22) - Math.max(y11,y21));
+          overlap_area = x_overlap * y_overlap;
+          ener += (overlap_area * w_lab2);
+          }
+
+          // penalty for label-anchor overlap
+          x11 = anc[i].x - anc[i].r;
+          y11 = anc[i].y - anc[i].r;
+          x12 = anc[i].x + anc[i].r;
+          y12 = anc[i].y + anc[i].r;
+          x_overlap = Math.max(0, Math.min(x12,x22) - Math.max(x11,x21));
+          y_overlap = Math.max(0, Math.min(y12,y22) - Math.max(y11,y21));
+          overlap_area = x_overlap * y_overlap;
+          ener += (overlap_area * w_lab_anc);
+
+      }
+      return ener;
+  };
+
+  mcmove = function(currT) {
+  // Monte Carlo translation move
+
+      // select a random label
+      var i = Math.floor(Math.random() * lab.length); 
+
+      // save old coordinates
+      var x_old = lab[i].x;
+      var y_old = lab[i].y;
+
+      // old energy
+      var old_energy;
+      if (user_energy) {old_energy = user_defined_energy(i, lab, anc)}
+      else {old_energy = energy(i)}
+
+      // random translation
+      lab[i].x += (Math.random() - 0.5) * max_move;
+      lab[i].y += (Math.random() - 0.5) * max_move;
+
+      // hard wall boundaries
+      if (lab[i].x > w) lab[i].x = x_old;
+      if (lab[i].x < 0) lab[i].x = x_old;
+      if (lab[i].y > h) lab[i].y = y_old;
+      if (lab[i].y < 0) lab[i].y = y_old;
+
+      // new energy
+      var new_energy;
+      if (user_energy) {new_energy = user_defined_energy(i, lab, anc)}
+      else {new_energy = energy(i)}
+
+      // delta E
+      var delta_energy = new_energy - old_energy;
+
+      if (Math.random() < Math.exp(-delta_energy / currT)) {
+        acc += 1;
+      } else {
+        // move back to old coordinates
+        lab[i].x = x_old;
+        lab[i].y = y_old;
+        rej += 1;
+      }
+
+  };
+
+  mcrotate = function(currT) {
+  // Monte Carlo rotation move
+
+      // select a random label
+      var i = Math.floor(Math.random() * lab.length); 
+
+      // save old coordinates
+      var x_old = lab[i].x;
+      var y_old = lab[i].y;
+
+      // old energy
+      var old_energy;
+      if (user_energy) {old_energy = user_defined_energy(i, lab, anc)}
+      else {old_energy = energy(i)}
+
+      // random angle
+      var angle = (Math.random() - 0.5) * max_angle;
+
+      var s = Math.sin(angle);
+      var c = Math.cos(angle);
+
+      // translate label (relative to anchor at origin):
+      lab[i].x -= anc[i].x
+      lab[i].y -= anc[i].y
+
+      // rotate label
+      var x_new = lab[i].x * c - lab[i].y * s,
+          y_new = lab[i].x * s + lab[i].y * c;
+
+      // translate label back
+      lab[i].x = x_new + anc[i].x
+      lab[i].y = y_new + anc[i].y
+
+      // hard wall boundaries
+      if (lab[i].x > w) lab[i].x = x_old;
+      if (lab[i].x < 0) lab[i].x = x_old;
+      if (lab[i].y > h) lab[i].y = y_old;
+      if (lab[i].y < 0) lab[i].y = y_old;
+
+      // new energy
+      var new_energy;
+      if (user_energy) {new_energy = user_defined_energy(i, lab, anc)}
+      else {new_energy = energy(i)}
+
+      // delta E
+      var delta_energy = new_energy - old_energy;
+
+      if (Math.random() < Math.exp(-delta_energy / currT)) {
+        acc += 1;
+      } else {
+        // move back to old coordinates
+        lab[i].x = x_old;
+        lab[i].y = y_old;
+        rej += 1;
+      }
+      
+  };
+
+  intersect = function(x1, x2, x3, x4, y1, y2, y3, y4) {
+  // returns true if two lines intersect, else false
+  // from http://paulbourke.net/geometry/lineline2d/
+
+    var mua, mub;
+    var denom, numera, numerb;
+
+    denom = (y4 - y3) * (x2 - x1) - (x4 - x3) * (y2 - y1);
+    numera = (x4 - x3) * (y1 - y3) - (y4 - y3) * (x1 - x3);
+    numerb = (x2 - x1) * (y1 - y3) - (y2 - y1) * (x1 - x3);
+
+    /* Is the intersection along the the segments */
+    mua = numera / denom;
+    mub = numerb / denom;
+    if (!(mua < 0 || mua > 1 || mub < 0 || mub > 1)) {
+        return true;
+    }
+    return false;
+  }
+
+  cooling_schedule = function(currT, initialT, nsweeps) {
+  // linear cooling
+    return (currT - (initialT / nsweeps));
+  }
+
+  labeler.start2 = function(nsweeps) {
+  // main simulated annealing function
+      var m = lab.length,
+          currT = 1.0,
+          initialT = 1.0;
+
+      for (var i = 0; i < nsweeps; i++) {
+        for (var j = 0; j < m; j++) { 
+          if (Math.random() < 0.5) { mcmove(currT); }
+          else { mcrotate(currT); }
+        }
+        currT = cooling_schedule(currT, initialT, nsweeps);
+      }
+  };
+
+  labeler.start = function(nsweeps) {
+  // main simulated annealing function
+      if(nsweeps <= 0)
+          return;
+
+      var m = lab.length,
+          currT = 1.0,
+          initialT = 1.0;
+
+      for (var j = 0; j < m; j++) { 
+          if (Math.random() < 0.5) { mcmove(currT); }
+          else { mcrotate(currT); }
+      }
+      update();
+      currT = cooling_schedule(currT, initialT, nsweeps);
+      setTimeout(labeler.start(nsweeps-1), 2);
+  };
+
+  labeler.width = function(x) {
+  // users insert graph width
+    if (!arguments.length) return w;
+    w = x;
+    return labeler;
+  };
+
+  labeler.height = function(x) {
+  // users insert graph height
+    if (!arguments.length) return h;
+    h = x;    
+    return labeler;
+  };
+
+  labeler.label = function(x) {
+  // users insert label positions
+    if (!arguments.length) return lab;
+    lab = x;
+    return labeler;
+  };
+
+  labeler.update = function(x) {
+  // users insert label positions
+    if (!arguments.length) return null;
+    update = x;
+    return labeler;
+  };
+
+  labeler.anchor = function(x) {
+  // users insert anchor positions
+    if (!arguments.length) return anc;
+    anc = x;
+    return labeler;
+  };
+
+  labeler.alt_energy = function(x) {
+  // user defined energy
+    if (!arguments.length) return energy;
+    user_defined_energy = x;
+    user_energy = true;
+    return labeler;
+  };
+
+  labeler.alt_schedule = function(x) {
+  // user defined cooling_schedule
+    if (!arguments.length) return  cooling_schedule;
+    user_defined_schedule = x;
+    user_schedule = true;
+    return labeler;
+  };
+
+  return labeler;
+};
+
+})();
+