LdaUtil { public static double digamma(double x) { return Gamma.digamma(x); }  static double digamma(double x); static void exp(DenseMatrix dm); static DenseMatrix expDirichletExpectation(DenseMatrix alpha); static double[] getTopicDistributionMethod(SparseVector sv,
                                                         DenseMatrix expELogBeta,
                                                         DenseMatrix alphaMatrix,
                                                         int topicNum); static HashMap<Integer, String> setWordIdWeightTrain(List<String> list); static HashMap<String, Tuple2<Integer, Double>> setWordIdWeightPredict(List<String> list);  }
@Test public void digammaTest() { double r = LdaUtil.digamma(1e-5); System.out.println(r); double r1 = LdaUtil.digamma(1e-100); System.out.println(r1); }