val SIGMA_FACTOR = 1.5

def calcAdjMatrix(users: Users, numeration: Seq[String]): DoubleMatrix = {
  val n = users.keys.size
  val distances = new DoubleMatrix(n, n)
  for (i <- (0 until n).par; j <- (i + 1 until n).par) {
    val a = users(numeration(i))
    val b = users(numeration(j))
    val diff = a.zip(b).map { case (x, y) => x - y }
    val dist = Measures.euclidNorm(diff)
    distances.put(i, j, dist)
    distances.put(j, i, dist)
  }
  val sigma = SIGMA_FACTOR * distances.data.sorted.apply(n * n / 2)
  val adj = distances.map { dist =>
    math.exp(-math.pow(dist, 2) / 2 / math.pow(sigma, 2))
  }
  0 until n foreach (i => adj.put(i, i, 0))
  adj
}