eNormal('x', 10, 5),
      sampleNormal('y', 10, 5),
      sampleNormal('c', 10, 5),
      sampleUniform('f', -1, 1),
      sampleInteger('x', 1, 100)
    ]);
    function generateData(n, samplers) {
      const data = Array(n);
      for (let i = 0; i < n; ++i) {
        data[i] = sampleDatum(samplers);
      }
      return data;
    }
    function sampleDatum(samplers) {
      const d = {}, n = samplers.length;
      for (let i = 0; i < n; ++i) {
        d[samplers[i].name] = samplers[i].sample();
      }