From feec778c6235a7ca76e97ed811d55b927a9b9584 Mon Sep 17 00:00:00 2001
From: Pitchaya Boonsarngsuk <2285135b@student.gla.ac.uk>
Date: Fri, 19 Jan 2018 09:29:14 +0000
Subject: [PATCH] Refactor: Extract functions

---
 ...3-force-neighbourSampling-papaparsing.html |   7 +-
 .../neighbourSampling-papaparsing/hybrid.js   |  43 +++++
 .../linkForce.js                              |  40 +++++
 .../neighbourSampling.js                      |  29 ++++
 .../otherAlgo.js                              |  43 +++++
 src/hybridSimulation.js                       |  16 +-
 src/interpolation.js                          | 153 ------------------
 src/interpolation/helpers.js                  |  48 ++++++
 src/interpolation/interpBruteForce.js         |  27 ++++
 src/interpolation/interpCommon.js             | 102 ++++++++++++
 .../interpolationPivots.js                    |   0
 src/neighbourSamplingDistance.js              |   6 +-
 12 files changed, 351 insertions(+), 163 deletions(-)
 create mode 100644 examples/js/src/neighbourSampling-papaparsing/hybrid.js
 create mode 100644 examples/js/src/neighbourSampling-papaparsing/linkForce.js
 create mode 100644 examples/js/src/neighbourSampling-papaparsing/neighbourSampling.js
 create mode 100644 examples/js/src/neighbourSampling-papaparsing/otherAlgo.js
 delete mode 100644 src/interpolation.js
 create mode 100644 src/interpolation/helpers.js
 create mode 100644 src/interpolation/interpBruteForce.js
 create mode 100644 src/interpolation/interpCommon.js
 rename src/{ => interpolation}/interpolationPivots.js (100%)

diff --git a/examples/d3-force-neighbourSampling-papaparsing.html b/examples/d3-force-neighbourSampling-papaparsing.html
index 71b828b..8f0159b 100644
--- a/examples/d3-force-neighbourSampling-papaparsing.html
+++ b/examples/d3-force-neighbourSampling-papaparsing.html
@@ -129,7 +129,7 @@
     <div class="left">
       <p>Select algorithm:</p>
       <div id="algorithms">
-        <input id="HLButton" type="radio" name="algorithm" onclick="d3.select('#startSimulation').on('click', startHybridSimulation)">Hybrid
+        <input id="HLButton" type="radio" name="algorithm" checked onclick="d3.select('#startSimulation').on('click', startHybridSimulation)">Hybrid
         layout
         <br>
         <div id="HLParameters" class="parameters" style="display:none">
@@ -232,7 +232,7 @@
     <div class="left">
       <p>Select distance function:</p>
       <div id="distance">
-        <input type="radio" name="distance" onclick="distanceFunction=calculateDistance"> General<br>
+        <input type="radio" name="distance" checked onclick="distanceFunction=calculateDistance"> General<br>
         <input type="radio" name="distance" onclick="distanceFunction=calculateEuclideanDistance"> Euclidean<br>
         <input type="radio" name="distance" onclick="distanceFunction=calculateManhattanDistance"> Manhattan<br>
         <input type="radio" name="distance" onclick="distanceFunction=calculateJaccardDissimilarity"> Jaccard<br>
@@ -252,6 +252,9 @@
 <script src="js/lib/intercom.js"></script>
 <script src="../build/d3-neighbour-sampling.js"></script>
 <script src="js/src/neighbourSampling-papaparsing.js"></script>
+<script src="js/src/neighbourSampling-papaparsing/hybrid.js"></script>
+<script src="js/src/neighbourSampling-papaparsing/linkForce.js"></script>
+<script src="js/src/neighbourSampling-papaparsing/neighbourSampling.js"></script>
 <script src="js/distances/distancePokerHands.js"></script>
 <script src="js/distances/distance.js"></script>
 <script src="js/distances/euclideanDistance.js"></script>
diff --git a/examples/js/src/neighbourSampling-papaparsing/hybrid.js b/examples/js/src/neighbourSampling-papaparsing/hybrid.js
new file mode 100644
index 0000000..321c34f
--- /dev/null
+++ b/examples/js/src/neighbourSampling-papaparsing/hybrid.js
@@ -0,0 +1,43 @@
+/**
+ * Initialize the hybrid layout algorithm and start simulation.
+ */
+function startHybridSimulation() {
+  console.log("startHybridSimulation");
+  springForce = false;
+  d3.selectAll(".nodes").remove();
+  simulation.stop();
+  p1 = performance.now();
+
+  configuration = {
+    iteration: ITERATIONS,
+    neighbourSize: NEIGHBOUR_SIZE,
+    sampleSize: SAMPLE_SIZE,
+    distanceRange: SELECTED_DISTANCE * MULTIPLIER,
+    fullIterations: FULL_ITERATIONS,
+    fullNeighbourSize: FULL_NEIGHBOUR_SIZE,
+    fullSampleSize: FULL_SAMPLE_SIZE,
+    fullDistanceRange: FULL_SELECTED_DISTANCE * MULTIPLIER,
+    distanceFn: function (s, t) {return distanceFunction(s, t, props, norm) * MULTIPLIER;},
+    pivots: PIVOTS,
+    numPivots: NUM_PIVOTS
+  };
+  console.log(configuration);
+  hybridSimulation = d3.hybridSimulation(nodes, configuration);
+
+  let sample = hybridSimulation.sample();
+  let remainder = hybridSimulation.remainder();
+
+  addNodesToDOM(sample);
+
+  hybridSimulation
+    .on("sampleTick", ticked)
+    .on("fullTick", ticked)
+    .on("startFull", startedFull)
+    .on("end", ended);
+
+  function startedFull() {
+    console.log("startedFull");
+    d3.selectAll(".nodes").remove();
+    addNodesToDOM(nodes);
+  }
+}
diff --git a/examples/js/src/neighbourSampling-papaparsing/linkForce.js b/examples/js/src/neighbourSampling-papaparsing/linkForce.js
new file mode 100644
index 0000000..97f07b5
--- /dev/null
+++ b/examples/js/src/neighbourSampling-papaparsing/linkForce.js
@@ -0,0 +1,40 @@
+
+/**
+ * Initialize the link force algorithm and start simulation.
+ */
+function startLinkSimulation() {
+  console.log("startLinkSimulation")
+  springForce = false;
+  simulation.stop();
+  p1 = performance.now();
+  let links = [];
+
+  // Initialize link array.
+  nodes = simulation.nodes();
+  for (i = 0; i < nodes.length; i++) {
+    for (j = 0; j < nodes.length; j++) {
+      if (i !== j) {
+        links.push({
+          source: nodes[i],
+          target: nodes[j],
+        });
+      }
+    }
+  }
+
+  // Add the links to the simulation.
+  simulation.force(forceName, d3.forceLink().links(links));
+
+  simulation
+    .alphaDecay(1 - Math.pow(0.001, 1 / ITERATIONS))
+    .force(forceName)
+    // The distance function that will be used to calculate distances
+    //  between nodes.
+    .distance(function (n) {
+      return distanceFunction(n.source, n.target, props, norm) * MULTIPLIER;
+    })
+    // Set the parameter for the algorithm (optional).
+    .strength(1);
+  // Restart the simulation.
+  simulation.alpha(1).restart();
+}
diff --git a/examples/js/src/neighbourSampling-papaparsing/neighbourSampling.js b/examples/js/src/neighbourSampling-papaparsing/neighbourSampling.js
new file mode 100644
index 0000000..1376492
--- /dev/null
+++ b/examples/js/src/neighbourSampling-papaparsing/neighbourSampling.js
@@ -0,0 +1,29 @@
+/**
+ * Initialize the Chalmers' 1996 algorithm and start simulation.
+ */
+function startNeighbourSamplingSimulation() {
+  console.log("startNeighbourSamplingSimulation");
+  springForce = true;
+  simulation.stop();
+  p1 = performance.now();
+
+  simulation
+    .alphaDecay(1 - Math.pow(0.001, 1 / ITERATIONS))
+    .force(forceName, d3.forceNeighbourSamplingDistance()
+      // Set the parameters for the algorithm (optional).
+      .neighbourSize(NEIGHBOUR_SIZE)
+      .sampleSize(SAMPLE_SIZE)
+      // .freeness(0.5)
+      .distanceRange(SELECTED_DISTANCE * MULTIPLIER)
+      // The distance function that will be used to calculate distances
+      //  between nodes.
+      .distance(function (s, t) {
+        return distanceFunction(s, t, props, norm) * MULTIPLIER;
+      })
+      .stableVelocity(1.2 * MULTIPLIER)
+      .stableVeloHandler( function(){simulation.stop(); ended();} )
+      );
+  // Restart the simulation.
+  console.log(simulation.force(forceName).neighbourSize(), simulation.force(forceName).sampleSize());
+  simulation.alpha(1).restart();
+}
diff --git a/examples/js/src/neighbourSampling-papaparsing/otherAlgo.js b/examples/js/src/neighbourSampling-papaparsing/otherAlgo.js
new file mode 100644
index 0000000..7cadba7
--- /dev/null
+++ b/examples/js/src/neighbourSampling-papaparsing/otherAlgo.js
@@ -0,0 +1,43 @@
+/**
+ * Initialize the t-SNE algorithm and start simulation.
+*/
+function starttSNE() {
+  springForce = false;
+  simulation.stop();
+  p1 = performance.now();
+
+  simulation
+    .alphaDecay(1 - Math.pow(0.001, 1 / ITERATIONS))
+    .force(forceName, d3.tSNE()
+      // Set the parameter for the algorithm (optional).
+      .perplexity(PERPLEXITY)
+      .learningRate(LEARNING_RATE)
+      // The distance function that will be used to calculate distances
+      //  between nodes.
+      .distance(function (s, t) {
+        return distanceFunction(s, t, props, norm) * MULTIPLIER;
+      }));
+  // Restart the simulation.
+  console.log(simulation.force(forceName).perplexity(), simulation.force(forceName).learningRate());
+  simulation.alpha(1).restart();
+}
+
+/**
+ * Initialize the Barnes-Hut algorithm and start simulation.
+*/
+function startBarnesHutSimulation() {
+  springForce = false;
+  simulation.stop();
+  p1 = performance.now();
+
+  simulation
+    .alphaDecay(1 - Math.pow(0.001, 1 / ITERATIONS))
+    .force(forceName, d3.forceBarnesHut()
+      // The distance function that will be used to calculate distances
+      //  between nodes.
+      .distance(function (s, t) {
+        return distanceFunction(s, t, props, norm) * MULTIPLIER;
+      }));
+  // Restart the simulation.
+  simulation.alpha(1).restart();
+}
diff --git a/src/hybridSimulation.js b/src/hybridSimulation.js
index 98c0c69..d620e25 100644
--- a/src/hybridSimulation.js
+++ b/src/hybridSimulation.js
@@ -1,8 +1,9 @@
 import { dispatch } from "d3-dispatch";
 import constant from "./constant";
-import interpolation from "./interpolation";
-import interpolationPivots from "./interpolationPivots";
+import interpBruteForce from "./interpolation/interpBruteForce";
+import interpolationPivots from "./interpolation/interpolationPivots";
 import neighbourSamplingDistance from "./neighbourSamplingDistance";
+import { takeSampleFrom } from "./interpolation/helpers";
 
 export default function (nodes, config) {
 
@@ -21,10 +22,9 @@ export default function (nodes, config) {
     NUMPIVOTS = config.hasOwnProperty("numPivots") ? config.numPivots : 3,
     event = d3.dispatch("sampleTick", "fullTick", "startFull", "end");
 
-  var sets = sampleFromNodes(nodes, Math.sqrt(nodes.length));
+  var sets = takeSampleFrom(nodes, Math.sqrt(nodes.length));
   var sample = sets.sample;
   var remainder = sets.remainder;
-  var sampleSubset = sampleFromNodes(sample, Math.sqrt(sample.length)).sample;
 
   var sampleSimulation = d3.forceSimulation(sample)
     .stop()
@@ -46,15 +46,19 @@ export default function (nodes, config) {
     .alpha(1).restart();
 
   function ended() {
+    sample.forEach(function (d) {
+      d.vx = 0;
+      d.vy = 0;
+    });
     event.call("startFull");
     console.log("Ended sample simulation");
     alert('About to interpolate');
-    interpolation(sample, remainder, sampleSubset, distanceFn);
+    interpBruteForce(sample, remainder, distanceFn);
     /*
     if (PIVOTS) {
       interpolationPivots(sample, remainder, sampleSubSet, NUMPIVOTS, distance);
     } else {
-      interpolation(sample, remainder, sampleSubSet, distance);
+      interpBruteForce(sample, remainder, sampleSubSet, distance);
     }
     */
     event.call("fullTick");
diff --git a/src/interpolation.js b/src/interpolation.js
deleted file mode 100644
index 9b7146d..0000000
--- a/src/interpolation.js
+++ /dev/null
@@ -1,153 +0,0 @@
-export default function(sampleSet, remainderSet, sampleSubset, distanceFn) {
-  // var distance = calculateEuclideanDistance;
-  // console.log("Brute-force");
-  for (let node of remainderSet) {
-    let nearestSample = undefined,
-        minDist = undefined,
-        sampleSubsetDistanceCache = [];
-
-    for (let sample of sampleSet) {
-      let dist = distanceFn(node, sample);
-      if (nearestSample === undefined || dist < minDist) {
-        minDist = dist;
-        nearestSample = sample;
-      }
-
-      let index = sampleSubset.indexOf(sample);
-      if (index !== -1) {
-        sampleSubsetDistanceCache[index] = dist;
-      }
-    }
-
-    placeNearToNearestNeighbour(node, nearestSample, minDist, sampleSubset, sampleSubsetDistanceCache);
-  }
-}
-
-
-function placeNearToNearestNeighbour(node, minNode, radius, sampleSubset, realDistances) {
-  let
-    dist0 = sumDistError(pointOnCircle(minNode.x, minNode.y, 0, radius), sampleSubset, realDistances),
-    dist90 = sumDistError(pointOnCircle(minNode.x, minNode.y, 90, radius), sampleSubset, realDistances),
-    dist180 = sumDistError(pointOnCircle(minNode.x, minNode.y, 180, radius), sampleSubset, realDistances),
-    dist270 = sumDistError(pointOnCircle(minNode.x, minNode.y, 270, radius), sampleSubset, realDistances),
-    lowBound = 0.0,
-    highBound = 0.0;
-
-  // Determine the closest quadrant
-  if (dist0 == dist180) {
-    if (dist90 > dist270)
-      lowBound = highBound = 270;
-    else
-      lowBound = highBound = 90;
-  } else if (dist90 == dist270) {
-    if (dist0 > dist180)
-      lowBound = highBound = 180;
-    else
-      lowBound = highBound = 0;
-  } else if (dist0 > dist180) {
-    if (dist90 > dist270) {
-      lowBound = 180;
-      highBound = 270;
-    } else {
-      lowBound = 90;
-      highBound = 180;
-    }
-  } else {
-    if (dist90 > dist270) {
-      lowBound = 270;
-      highBound = 360;
-    } else {
-      lowBound = 0;
-      highBound = 90;
-    }
-  }
-
-  let angle = binarySearchMin(lowBound, highBound,
-                             function(angle){
-                               return sumDistError(pointOnCircle(minNode.x, minNode.y, angle, radius), sampleSubset, realDistances);
-                             });
-  let newPoint = pointOnCircle(minNode.x, minNode.y, angle, radius);
-
-  // console.log(newPoint);
-  node.x = newPoint.x;
-  node.y = newPoint.y;
-
-  for (let i = 0; i < 20; i++) {
-    let forces = sumForcesToSample(node, sampleSubset, realDistances);
-    // console.log(forces);
-    node.x += forces.x*0.5;
-    node.y += forces.y*0.5;
-  }
-
-}
-
-// With a circle radius r, and center at (h,k),
-// Find the coordinate of a point at angle degree
-function pointOnCircle(h, k, angle, r) {
-  let x = h + r*Math.cos(toRadians(angle));
-  let y = k + r*Math.sin(toRadians(angle));
-
-  return {
-    x: x,
-    y: y
-  };
-}
-
-function toRadians(degrees) {
-  return degrees * (Math.PI / 180);
-}
-
-function sumDistError(currentPos, samples, realDistances) {
-  let total = 0.0;
-  for (let i = 0; i < samples.length; i++) {
-    let sample = samples[i];
-    let lowDDistance = Math.hypot(sample.x - currentPos.x, sample.y - currentPos.y);
-    total += Math.abs(lowDDistance - realDistances[i]);
-  }
-  return total;
-}
-
-
-function sumForcesToSample(node, samples, sampleCache) {
-  let nodeVx = 0,
-      nodeVy = 0;
-
-  for (let i = 0; i < samples.length; i++) {
-    var sample = samples[i];
-    if(sample === node) continue;
-
-    let x = node.x - sample.x,
-        y = node.y - sample.y,
-        l = Math.sqrt(x * x + y * y);
-
-    l = (l - sampleCache[i]) / l;
-    x *= l, y *= l;
-    nodeVx -= x;
-    nodeVy -= y;
-  }
-  return {x: nodeVx, y: nodeVy};
-}
-
-function binarySearchMin(lb, hb, fn) {
-  while (lb <= hb) {
-    if(lb === hb) return lb;
-    if(hb-lb == 1) {
-      if (fn(lb) >= fn(hb)) return hb;
-      else return lb;
-    }
-
-    let range = hb-lb;
-    let valLowerHalf = fn(lb + range/4);
-    let valHigherHalf = fn(lb + range*3/4);
-
-    if (valLowerHalf > valHigherHalf)
-      lb = Math.floor((lb + hb) / 2);
-    else if (valLowerHalf < valHigherHalf)
-      hb = Math.ceil((lb + hb) / 2);
-    else {
-      lb += Math.floor(range/4);
-      hb -= Math.ceil(range/4);
-    }
-  }
-  return -1;
-}
diff --git a/src/interpolation/helpers.js b/src/interpolation/helpers.js
new file mode 100644
index 0000000..38d9930
--- /dev/null
+++ b/src/interpolation/helpers.js
@@ -0,0 +1,48 @@
+export function takeSampleFrom(nodes, amount) {
+  let randElements = [],
+      max = nodes.length;
+
+  for (var i = 0; i < amount; ++i) {
+    var rand = nodes[Math.floor((Math.random() * max))];
+    // If the rand is already in random list or in exclude list
+    // ignore it and get a new value.
+    while (randElements.includes(rand)) {
+      rand = nodes[Math.floor((Math.random() * max))];
+    }
+    randElements.push(rand);
+  }
+  var remainder = nodes.filter(function (node) {
+    return !randElements.includes(node);
+  });
+
+  return {
+    sample: randElements,
+    remainder: remainder
+  };
+}
+
+// With a circle radius r, and center at (h,k),
+// Find the coordinate of a point at angle degree
+export function pointOnCircle(h, k, angle, r) {
+  let x = h + r*Math.cos(toRadians(angle));
+  let y = k + r*Math.sin(toRadians(angle));
+
+  return {
+    x: x,
+    y: y
+  };
+}
+
+function toRadians(degrees) {
+  return degrees * (Math.PI / 180);
+}
+
+export function sumDistError(node, samples, realDistances) {
+  let total = 0.0;
+  for (let i = 0; i < samples.length; i++) {
+    let sample = samples[i];
+    let lowDDistance = Math.hypot(sample.x - node.x, sample.y - node.y);
+    total += Math.abs(lowDDistance - realDistances[i]);
+  }
+  return total;
+}
diff --git a/src/interpolation/interpBruteForce.js b/src/interpolation/interpBruteForce.js
new file mode 100644
index 0000000..27748e7
--- /dev/null
+++ b/src/interpolation/interpBruteForce.js
@@ -0,0 +1,27 @@
+import { pointOnCircle, takeSampleFrom } from "./helpers";
+import { placeNearToNearestNeighbour } from "./interpCommon";
+
+export default function(sampleSet, remainderSet, distanceFn) {
+  // var distance = calculateEuclideanDistance;
+  // console.log("Brute-force");
+  let sampleSubset = takeSampleFrom(sampleSet, Math.sqrt(sampleSet.length)).sample;
+
+  for (let node of remainderSet) {
+    let nearestSample = undefined,
+        minDist = undefined,
+        sampleSubsetDistanceCache = [];
+
+    for (let sample of sampleSet) {
+      let dist = distanceFn(node, sample);
+      if (nearestSample === undefined || dist < minDist) {
+        minDist = dist;
+        nearestSample = sample;
+      }
+
+      let index = sampleSubset.indexOf(sample);
+      if (index !== -1)
+        sampleSubsetDistanceCache[index] = dist;
+    }
+    placeNearToNearestNeighbour(node, nearestSample, minDist, sampleSubset, sampleSubsetDistanceCache);
+  }
+}
diff --git a/src/interpolation/interpCommon.js b/src/interpolation/interpCommon.js
new file mode 100644
index 0000000..4966c4c
--- /dev/null
+++ b/src/interpolation/interpCommon.js
@@ -0,0 +1,102 @@
+import { pointOnCircle, sumDistError } from "./helpers";
+
+export function placeNearToNearestNeighbour(node, nearNeighbour, radius, sampleSubset, realDistances) {
+  let
+    dist0 = sumDistError(pointOnCircle(nearNeighbour.x, nearNeighbour.y, 0, radius), sampleSubset, realDistances),
+    dist90 = sumDistError(pointOnCircle(nearNeighbour.x, nearNeighbour.y, 90, radius), sampleSubset, realDistances),
+    dist180 = sumDistError(pointOnCircle(nearNeighbour.x, nearNeighbour.y, 180, radius), sampleSubset, realDistances),
+    dist270 = sumDistError(pointOnCircle(nearNeighbour.x, nearNeighbour.y, 270, radius), sampleSubset, realDistances),
+    lowBound = 0.0,
+    highBound = 0.0;
+
+  // Determine the closest quadrant
+  if (dist0 == dist180) {
+    if (dist90 > dist270)
+      lowBound = highBound = 270;
+    else
+      lowBound = highBound = 90;
+  } else if (dist90 == dist270) {
+    if (dist0 > dist180)
+      lowBound = highBound = 180;
+    else
+      lowBound = highBound = 0;
+  } else if (dist0 > dist180) {
+    if (dist90 > dist270) {
+      lowBound = 180;
+      highBound = 270;
+    } else {
+      lowBound = 90;
+      highBound = 180;
+    }
+  } else {
+    if (dist90 > dist270) {
+      lowBound = 270;
+      highBound = 360;
+    } else {
+      lowBound = 0;
+      highBound = 90;
+    }
+  }
+
+  let angle = binarySearchMin(lowBound, highBound,
+                             function(angle){
+                               return sumDistError(pointOnCircle(nearNeighbour.x, nearNeighbour.y, angle, radius), sampleSubset, realDistances);
+                             });
+  let newPoint = pointOnCircle(nearNeighbour.x, nearNeighbour.y, angle, radius);
+
+  // console.log(newPoint);
+  node.x = newPoint.x;
+  node.y = newPoint.y;
+
+  for (let i = 0; i < 20; i++) {
+    let forces = sumForcesToSample(node, sampleSubset, realDistances);
+    //console.log(forces);
+    node.x += forces.x*0.5;
+    node.y += forces.y*0.5;
+  }
+}
+
+function sumForcesToSample(node, samples, sampleCache) {
+  let nodeVx = 0,
+      nodeVy = 0;
+
+  for (let i = 0; i < samples.length; i++) {
+    var sample = samples[i];
+    if(sample === node) continue;
+
+    let x = node.x - sample.x,
+        y = node.y - sample.y,
+        l = Math.sqrt(x * x + y * y);
+
+    l = (l - sampleCache[i]) / l;
+    x *= l, y *= l;
+    nodeVx -= x;
+    nodeVy -= y;
+  }
+  return {x: nodeVx, y: nodeVy};
+}
+
+function binarySearchMin(lb, hb, fn) {
+  while (lb <= hb) {
+    if(lb === hb) return lb;
+
+    if(hb-lb == 1) {
+      if (fn(lb) >= fn(hb)) return hb;
+      else return lb;
+    }
+
+    let range = hb-lb;
+    let valLowerHalf = fn(lb + range/4);
+    let valHigherHalf = fn(lb + range*3/4);
+
+    if (valLowerHalf > valHigherHalf)
+      lb = Math.floor((lb + hb) / 2);
+    else if (valLowerHalf < valHigherHalf)
+      hb = Math.ceil((lb + hb) / 2);
+    else {
+      lb += Math.floor(range/4);
+      hb -= Math.ceil(range/4);
+    }
+  }
+  return -1;
+}
diff --git a/src/interpolationPivots.js b/src/interpolation/interpolationPivots.js
similarity index 100%
rename from src/interpolationPivots.js
rename to src/interpolation/interpolationPivots.js
diff --git a/src/neighbourSamplingDistance.js b/src/neighbourSamplingDistance.js
index 4c20b56..9a61001 100644
--- a/src/neighbourSamplingDistance.js
+++ b/src/neighbourSamplingDistance.js
@@ -56,8 +56,10 @@ export default function () {
       // for each node.
       findNewNeighbours(i);
     }
-    velocity /= nodes.length*alpha;
-    // Now total velocity changes per node, alpha not considered
+    velocity /= nodes.length*(neighbours.length+samples.length)*alpha;
+    // Now total velocity changes per link, alpha not considered
+    // TODO per property too
+    stableVelocity = 0;
     if(Math.abs(velocity)<stableVelocity && stableVeloHandler!== null){
       console.log("Neighbour sampling is now", velocity, ", calling stableVeloHandler().")
       stableVeloHandler();