code: function converged(centers, oldCenters, distanceFunction, tolerance) {
                  for (var i = 0; i < centers.length; i++) {
                      if (distanceFunction(centers[i], oldCenters[i]) > tolerance) {
                          return false;
                      }
                  }
                  return true;
              }
docs: The centers have moved more than the tolerance value?
  @ignore
  @param {Array<Array<Number>>} centers - the K centers in format [x,y,z,...]
  @param {Array<Array<Number>>} oldCenters - the K old centers in format [x,y,z,...]
  @param {Function} distanceFunction - Distance function to use between the points
  @param {Number} tolerance - Allowed distance for the centroids to move
  @return {boolean}