/**
 * 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)
      // The distance function that will be used to calculate distances
      //  between nodes.
      .distance(function (s, t) {
        return distanceFunction(s, t, props, norm);
      })
      .stableVelocity(0.004)
      .stableVeloHandler( function(){simulation.stop(); ended();} )
      );
  // Restart the simulation.
  console.log(simulation.force(forceName).neighbourSize(), simulation.force(forceName).sampleSize());
  simulation.alpha(1).restart();
}