weka.core.Instances.instance()方法的使用及代码示例

x33g5p2x  于2022-01-21 转载在 其他  
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本文整理了Java中weka.core.Instances.instance()方法的一些代码示例，展示了Instances.instance()的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Instances.instance()方法的具体详情如下：
包路径：weka.core.Instances
类名称：Instances
方法名：instance

Instances.instance介绍

[英]Returns the instance at the given position.
[中]返回给定位置的实例。

代码示例

代码示例来源：origin: net.sf.meka/meka

/**
 * Stack two Instances together row-wise.
 */
public static final Instances combineInstances(Instances D1, Instances D2) {
  Instances D = new Instances(D1);
  for(int i = 0; i < D2.numInstances(); i++) {
    D.add(D2.instance(i));
  }
  return D;
}

代码示例来源：origin: nz.ac.waikato.cms.weka/distributedWekaBase

/**
 * Add the supplied instances to the training header
 *
 * @param toAdd the instances to add
 */
public void addToTrainingHeader(Instances toAdd) {
 for (int i = 0; i < toAdd.numInstances(); i++) {
  m_trainingHeader.add(toAdd.instance(i));
 }
}

代码示例来源：origin: net.sf.meka/meka

/** 
 * LabelCardinality - return the label cardinality of dataset D of L labels.
 */
public static final double labelCardinality(Instances D, int L) {
  double sum = 0.0;
  double numInstances = (double)D.numInstances();
  for(int i = 0; i < D.numInstances(); i++) {
    for(int j = 0; j < L; j++) {
    if (!D.instance(i).isMissing(j)) {
      sum += D.instance(i).value(j);
    }
    }
  }
  return (double)sum/ numInstances;
}

代码示例来源：origin: nz.ac.waikato.cms.weka/weka-stable

public void testFloor() {
 m_Filter = getFilter("floor(a6+a3/5)");
 Instances result = useFilter();
 for (int i = 0; i < result.numInstances(); i++) {
  Instance inst = result.instance(i);
  assertEquals("Instance " + (i + 1),
         Math.floor(inst.value(5) + inst.value(2)/5), 
         inst.value(inst.numAttributes() - 1), EXPR_DELTA);
 }
}

代码示例来源：origin: nz.ac.waikato.cms.weka/weka-stable

protected void initMinMax(Instances data) {
 m_Min = new double[data.numAttributes()];
 m_Max = new double[data.numAttributes()];
 for (int i = 0; i < data.numAttributes(); i++) {
  m_Min[i] = m_Max[i] = Double.NaN;
 }
 for (int i = 0; i < data.numInstances(); i++) {
  updateMinMax(data.instance(i));
 }
}

代码示例来源：origin: net.sf.meka/meka

@Override
public Instance transformInstance(Instance x) throws Exception{

Instances tmpInst = new Instances(x.dataset());
tmpInst.delete();
tmpInst.add(x);

Instances features = this.extractPart(tmpInst, false);
Instances pseudoLabels = new Instances(this.compressedTemplateInst);
Instance tmpin = pseudoLabels.instance(0);
pseudoLabels.delete();

pseudoLabels.add(tmpin);
for ( int i = 0; i< pseudoLabels.classIndex(); i++) {
  pseudoLabels.instance(0).setMissing(i);
}
Instances newDataSet = Instances.mergeInstances(pseudoLabels, features);
newDataSet.setClassIndex(pseudoLabels.numAttributes());

return newDataSet.instance(0);
}

代码示例来源：origin: Waikato/meka

@Override
public Instance transformInstance(Instance x) throws Exception{
Instances tmpInst = new Instances(x.dataset());
tmpInst.delete();
tmpInst.add(x);

Instances features = this.extractPart(tmpInst, false);
Instances pseudoLabels = new Instances(this.compressedMatrix);
Instance tmpin = pseudoLabels.instance(0);
pseudoLabels.delete();
pseudoLabels.add(tmpin);
for ( int i = 0; i< pseudoLabels.classIndex(); i++) {
  pseudoLabels.instance(0).setMissing(i);
}
Instances newDataSet = Instances.mergeInstances(pseudoLabels, features);
newDataSet.setClassIndex(this.size);

return newDataSet.instance(0);
}

代码示例来源：origin: nz.ac.waikato.cms.weka/weka-stable

public void testPruneMinFreq() throws Exception {
 Instances data1 = getData1();
 Instances structure = new Instances(data1, 0);
 DictionaryBuilder builder = new DictionaryBuilder();
 builder.setMinTermFreq(1);
 builder.setup(structure);
 for (int i = 0; i < data1.numInstances(); i++) {
  builder.processInstance(data1.instance(i));
 }
 assertEquals(15, builder.getDictionaries(false)[0].size());
 Map<String, int[]> consolidated = builder.finalizeDictionary();
 // min freq of 1 should keep all terms
 assertEquals(15, consolidated.size());
}

代码示例来源：origin: nz.ac.waikato.cms.weka/weka-stable

/**
 * Calculates the distribution, in the dataset, of the indexed nominal
 * attribute values. It also counts the actual number of training instances
 * that contributed (those with non-missing values) to calculate the
 * distribution.
 */
private void generateAttrDistribution() {
 m_Distribution = new int[m_TrainSet.attribute(m_AttrIndex).numValues()];
 int i;
 Instance train;
 for (i = 0; i < m_NumInstances; i++) {
  train = m_TrainSet.instance(i);
  if (!train.isMissing(m_AttrIndex)) {
   m_TotalCount++;
   m_Distribution[(int) train.value(m_AttrIndex)]++;
  }
 }
}

代码示例来源：origin: Waikato/meka

/** 
 * LabelCardinality - return the label cardinality of dataset D of L labels.
 */
public static final double labelCardinality(Instances D, int L) {
  double sum = 0.0;
  double numInstances = (double)D.numInstances();
  for(int i = 0; i < D.numInstances(); i++) {
    for(int j = 0; j < L; j++) {
    if (!D.instance(i).isMissing(j)) {
      sum += D.instance(i).value(j);
    }
    }
  }
  return (double)sum/ numInstances;
}

代码示例来源：origin: Waikato/meka

/**
 * Stack two Instances together row-wise.
 */
public static final Instances combineInstances(Instances D1, Instances D2) {
  Instances D = new Instances(D1);
  for(int i = 0; i < D2.numInstances(); i++) {
    D.add(D2.instance(i));
  }
  return D;
}

代码示例来源：origin: nz.ac.waikato.cms.weka/weka-stable

public void testExp() {
 m_Filter = getFilter("exp(a6-a3)");
 Instances result = useFilter();
 for (int i = 0; i < result.numInstances(); i++) {
  Instance inst = result.instance(i);
  assertEquals("Instance " + (i + 1),
         Math.exp(inst.value(5) - inst.value(2)), 
         inst.value(inst.numAttributes() - 1), EXPR_DELTA);
 }
}

代码示例来源：origin: Waikato/weka-trunk

protected void initMinMax(Instances data) {
 m_Min = new double[data.numAttributes()];
 m_Max = new double[data.numAttributes()];
 for (int i = 0; i < data.numAttributes(); i++) {
  m_Min[i] = m_Max[i] = Double.NaN;
 }
 for (int i = 0; i < data.numInstances(); i++) {
  updateMinMax(data.instance(i));
 }
}

代码示例来源：origin: Waikato/meka

@Override
public Instance transformInstance(Instance x) throws Exception{

Instances tmpInst = new Instances(x.dataset());
tmpInst.delete();
tmpInst.add(x);

Instances features = this.extractPart(tmpInst, false);
Instances pseudoLabels = new Instances(this.compressedTemplateInst);
Instance tmpin = pseudoLabels.instance(0);
pseudoLabels.delete();

pseudoLabels.add(tmpin);
for ( int i = 0; i< pseudoLabels.classIndex(); i++) {
  pseudoLabels.instance(0).setMissing(i);
}
Instances newDataSet = Instances.mergeInstances(pseudoLabels, features);
newDataSet.setClassIndex(pseudoLabels.numAttributes());

return newDataSet.instance(0);
}

代码示例来源：origin: nz.ac.waikato.cms.weka/weka-stable

public void testFinalizeDictionaryNoClassExtraAtts() throws Exception {
 Instances data1 = getData3();
 Instances structure = new Instances(data1, 0);
 DictionaryBuilder builder = new DictionaryBuilder();
 builder.setMinTermFreq(2);
 builder.setup(structure);
 for (int i = 0; i < data1.numInstances(); i++) {
  builder.processInstance(data1.instance(i));
 }
 assertEquals(15, builder.getDictionaries(false)[0].size());
 Map<String, int[]> consolidated = builder.finalizeDictionary();
 // all but "the" and "over" should have been pruned from the dictionary
 assertEquals(2, consolidated.size());
}

代码示例来源：origin: Waikato/weka-trunk

/**
 * Calculates the distribution, in the dataset, of the indexed nominal
 * attribute values. It also counts the actual number of training instances
 * that contributed (those with non-missing values) to calculate the
 * distribution.
 */
private void generateAttrDistribution() {
 m_Distribution = new int[m_TrainSet.attribute(m_AttrIndex).numValues()];
 int i;
 Instance train;
 for (i = 0; i < m_NumInstances; i++) {
  train = m_TrainSet.instance(i);
  if (!train.isMissing(m_AttrIndex)) {
   m_TotalCount++;
   m_Distribution[(int) train.value(m_AttrIndex)]++;
  }
 }
}

代码示例来源：origin: nz.ac.waikato.cms.weka/weka-stable

/**
 * Adds the supplied node as a child of this node. All of the child's
 * instances are added to this nodes instances
 * 
 * @param child the child to add
 */
protected void addChildNode(CNode child) {
 for (int i = 0; i < child.m_clusterInstances.numInstances(); i++) {
  Instance temp = child.m_clusterInstances.instance(i);
  m_clusterInstances.add(temp);
  updateStats(temp, false);
 }
 if (m_children == null) {
  m_children = new ArrayList<CNode>();
 }
 m_children.add(child);
}

代码示例来源：origin: Waikato/meka

/**
 * jPMF - Joint PMF.
 * @return the joint PMF of the j-th and k-th labels in D.
 */
public static double[][] jPMF(Instances D, int j, int k) {
  double JOINT[][] = new double[D.attribute(j).numValues()][D.attribute(k).numValues()];
  int N = D.numInstances();
  for(int i = 0; i < N; i++) {
    int v_j = (int)Math.round(D.instance(i).value(j));
    int v_k = (int)Math.round(D.instance(i).value(k));
    JOINT[v_j][v_k] += (1.0 / (double)N);
  }
  return JOINT;
}

代码示例来源：origin: nz.ac.waikato.cms.weka/meka

public static final Instances combineInstances(Instances D1, Instances D2) {
  Instances D = new Instances(D1);
  for(int i = 0; i < D2.numInstances(); i++) {
    D.add(D2.instance(i));
  }
  return D;
}

代码示例来源：origin: nz.ac.waikato.cms.weka/weka-stable

public void testCeil() {
 m_Filter = getFilter("ceil(a6*a3/5)");
 Instances result = useFilter();
 for (int i = 0; i < result.numInstances(); i++) {
  Instance inst = result.instance(i);
  assertEquals("Instance " + (i + 1),
         Math.ceil(inst.value(5) * inst.value(2)/5), 
         inst.value(inst.numAttributes() - 1), EXPR_DELTA);
 }
}

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