jtBaseApp/node_modules/density-clustering/test/OPTICS.test.js

require('should');
var clustering = require('../lib/index.js');
var OPTICS = clustering.OPTICS;

describe('OPTICS', function() {

  describe('run', function() {
    it('should test regular density set', function() {
      var dataset = [
        [1, 1], [0, 1], [1, 0],
        [10, 10], [10, 11], [11, 10],
        [50, 50], [51, 50], [50, 51],
        [100, 100]
      ];

      var optics = new OPTICS();
      var clusters = optics.run(dataset, 2, 2);

      clusters.should.be.eql([
        [0, 1, 2],
        [3, 4, 5],
        [6, 7, 8],
        [9]
      ]);
    });

    it('should test various density set', function() {
      var dataset = [
        [0, 0], [6, 0], [-1, 0], [0, 1], [0, -1],
        [45, 45], [45.1, 45.2], [45.1, 45.3], [45.8, 45.5],
        [45.2, 45.3],
        [50, 50], [56, 50], [50, 52], [50, 55], [50, 51]
      ];
      var optics = new OPTICS();
      var clusters = optics.run(dataset, 6, 2);

      clusters.should.be.eql([
        [0, 2, 3, 4],
        [1],
        [5, 6, 7, 9, 8],
        [10, 14, 12, 13],
        [11]
      ]);
    });
  });

  describe('regionQuery', function() {
    it('should return nearest neighborhood of a point', function() {
      var optics = new OPTICS();
      optics.dataset = [
        [1, 1], [2, 2], [3, 3],
        [50, 50], [51, 51]
      ];
      optics.epsilon = 2;
      optics._regionQuery(1).should.eql([0, 1, 2]);
      optics._regionQuery(4).should.eql([3, 4]);

      optics.epsilon = 100;
      optics._regionQuery(1).should.eql([0, 1, 2, 3, 4]);
    });
  });

  describe('euclideanDistance', function() {
    it('should return distance between two points', function() {
      var optics = new OPTICS();
      optics._euclideanDistance([1, 1], [3, 1]).should.eql(2);
      optics._euclideanDistance([1, 1], [1, 3]).should.eql(2);
    });
  });

  describe('getReachabilityPlot', function() {
    it('should return reachability plot', function() {
      var optics = new OPTICS();
      var plot;

      var dataset = [
        [1, 1], [0, 1], [1, 0],
        [10, 10], [10, 11], [11, 10]
      ];

      optics.run(dataset, 2, 2);
      plot = optics.getReachabilityPlot();
      plot.should.eql([
        [0, undefined], [1, 1], [2, 1],
        [3, undefined], [4, 1], [5, 1]
      ]);

      // reachability plot should be always the same for different epsilon values
      optics.run(dataset, 10, 2);
      plot = optics.getReachabilityPlot();
      plot.should.eql([
        [0, undefined], [1, 1], [2, 1],
        [3, undefined], [4, 1], [5, 1]
      ]);
    });
  });

});