From cf813a58c8b0e6e505eccc6316ce6256c5c85ef6 Mon Sep 17 00:00:00 2001
From: Pitchaya Boonsarngsuk <2285135b@student.gla.ac.uk>
Date: Mon, 5 Feb 2018 16:33:46 +0000
Subject: [PATCH] Neighbour change api

---
 examples/js/src/example-papaparsing/hybrid.js      |  1 +
 .../src/example-papaparsing/neighbourSampling.js   |  2 +-
 src/hybridSimulation.js                            |  8 +++-----
 src/neighbourSampling.js                           | 14 ++++++++------
 4 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/examples/js/src/example-papaparsing/hybrid.js b/examples/js/src/example-papaparsing/hybrid.js
index 551ae1f..57d2db5 100644
--- a/examples/js/src/example-papaparsing/hybrid.js
+++ b/examples/js/src/example-papaparsing/hybrid.js
@@ -16,6 +16,7 @@ function startHybridSimulation() {
   let forceSample = d3.forceNeighbourSampling()
     .neighbourSize(NEIGHBOUR_SIZE)
     .sampleSize(SAMPLE_SIZE)
+    .stableVelocity(0)
     .distance(distance)
 
   let forceFull = d3.forceNeighbourSampling()
diff --git a/examples/js/src/example-papaparsing/neighbourSampling.js b/examples/js/src/example-papaparsing/neighbourSampling.js
index 40f8603..ee11d4e 100644
--- a/examples/js/src/example-papaparsing/neighbourSampling.js
+++ b/examples/js/src/example-papaparsing/neighbourSampling.js
@@ -16,7 +16,7 @@ function startNeighbourSamplingSimulation() {
                     return distanceFunction(s, t, props, norm);
                   })
                   .stableVelocity(0.000001) //TODO
-                  .stableVeloHandler(ended);
+                  .onStableVelo(ended);
 
   simulation
     .alphaDecay(0)
diff --git a/src/hybridSimulation.js b/src/hybridSimulation.js
index 524cfad..260efd3 100644
--- a/src/hybridSimulation.js
+++ b/src/hybridSimulation.js
@@ -15,7 +15,7 @@ import {takeSampleFrom} from "./interpolation/helpers";
  * clean up the model.
  * @param {object} sim    - D3 Simulation object
  * @param {object} forceS - Pre-configured D3 force object for the sample set.
-                            The ending condition will be re-configured.
+                            The ending handler will be re-configured.
                             Neighbour sampling force is expected, but other D3
                             forces may also work.
  * @param {object} forceF - Pre-configured D3 force object for the simultion ran
@@ -60,10 +60,8 @@ export default function (sim, forceS, forceF) {
   }
 
   function initForces(){
-    if (forceSample.stableVelocity && forceSample.stableVeloHandler) {
-      forceSample
-        .stableVelocity(0) //TODO
-        .stableVeloHandler(sampleEnded);
+    if (forceSample.onStableVelo) {
+      forceSample.onStableVelo(sampleEnded);
     }
 
     // Set default value for interpDistanceFn if not been specified yet
diff --git a/src/neighbourSampling.js b/src/neighbourSampling.js
index 7445a10..0cc134a 100644
--- a/src/neighbourSampling.js
+++ b/src/neighbourSampling.js
@@ -20,7 +20,8 @@ export default function () {
     sampleSize = 10,
     stableVelocity = 0,
     stableVeloHandler = null,
-    dataSizeFactor;
+    dataSizeFactor,
+    latestVelocityDiff = 0;
 
   /**
    * Apply spring forces at each simulation iteration.
@@ -29,7 +30,7 @@ export default function () {
   function force(alpha) {
     let n = nodes.length;
     // Cache old velocity for comparison later
-    if (stableVeloHandler!==null && stableVelocity!=0) {
+    if (stableVeloHandler!==null && stableVelocity>=0) {
       for (let i = n-1, node; i>=0; i--) {
         node = nodes[i];
         node.oldvx = node.vx;
@@ -53,13 +54,14 @@ export default function () {
     }
 
     // Calculate velocity changes, aka force applied.
-    if (stableVeloHandler!==null && stableVelocity!=0) {
+    if (stableVeloHandler!==null && stableVelocity>=0) {
       let velocityDiff = 0;
       for (let i = n-1, node; i>=0; i--) {
         node = nodes[i];
         velocityDiff += Math.abs(Math.hypot(node.vx-node.oldvx, node.vy-node.oldvy));
       }
       velocityDiff /= n*(neighbourSize+sampleSize);
+      latestVelocityDiff = velocityDiff;
 
       if(stableVeloHandler!==null && velocityDiff<stableVelocity){
         stableVeloHandler();
@@ -191,11 +193,11 @@ export default function () {
     return arguments.length ? (distance = typeof _ === "function" ? _ : constant(+_), force) : distance;
   };
 
-  force.velocity = function () {
-    return getAvgVelocity();
+  force.latestAccel = function () {
+    return latestVelocityDiff;
   };
 
-  force.stableVeloHandler = function (_) {
+  force.onStableVelo = function (_) {
     return arguments.length ? (stableVeloHandler = _, force) : stableVeloHandler;
   };