本文整理了Java中org.apache.mahout.math.Matrix.viewColumn()方法的一些代码示例，展示了Matrix.viewColumn()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。Matrix.viewColumn()方法的具体详情如下：
包路径：org.apache.mahout.math.Matrix
类名称：Matrix
方法名：viewColumn

Matrix.viewColumn介绍

[英]Return a reference to a column. Changes to the view will change the original matrix.
[中]返回对列的引用。对视图的更改将更改原始矩阵。

代码示例

代码示例来源：origin: apache/mahout

@Override
public Vector viewRow(int row) {
 return m.viewColumn(row);
}

代码示例来源：origin: apache/mahout

@Override
public Vector like(int cardinality) {
 return matrix.like(cardinality, 1).viewColumn(0);
}

代码示例来源：origin: apache/mahout

@Override
public double getQuick(int index) {
 Vector v = rowToColumn ? matrix.viewColumn(index) : matrix.viewRow(index);
 return v == null ? 0.0 : v.getQuick(transposeOffset);
}

代码示例来源：origin: apache/mahout

@Override
 public boolean isAddConstantTime() {
  return (rowToColumn ? matrix.viewColumn(0) : matrix.viewRow(0)).isAddConstantTime();
 }
}

代码示例来源：origin: apache/mahout

/**
 * Return an empty vector of the same underlying class as the receiver
 *
 * @return a Vector
 */
@Override
public Vector like() {
 return matrix.like(size(), 1).viewColumn(0);
}

代码示例来源：origin: apache/mahout

@Override
public double getLookupCost() {
 return (rowToColumn ? matrix.viewColumn(0) : matrix.viewRow(0)).getLookupCost();
}

代码示例来源：origin: apache/mahout

@Override
public double getIteratorAdvanceCost() {
 return (rowToColumn ? matrix.viewColumn(0) : matrix.viewRow(0)).getIteratorAdvanceCost();
}

代码示例来源：origin: apache/mahout

@Test(expected = IndexException.class)
public void testViewColumnIndexUnder() {
 test.viewColumn(-1);
}

代码示例来源：origin: apache/mahout

@Test(expected = IndexException.class)
public void testViewColumnIndexOver() {
 test.viewColumn(5);
}

代码示例来源：origin: apache/mahout

@Test(expected = IndexException.class)
public void testViewColumnIndexUnder() {
 test.viewColumn(-1);
}

代码示例来源：origin: apache/mahout

@Test(expected = IndexException.class)
public void testViewColumnIndexOver() {
 test.viewColumn(5);
}

代码示例来源：origin: apache/mahout

@Override
public Vector viewColumn(int column) {
 if (column < 0 || column >= columnSize()) {
  throw new IndexException(column, columnSize());
 }
 return matrix.viewColumn(column + offset[COL]).viewPart(offset[ROW], rowSize());
}

代码示例来源：origin: apache/mahout

@Override
public Matrix timesLeft(Matrix that) {
 if (that.numCols() != diagonal.size()) {
  throw new IllegalArgumentException(
   "Incompatible number of rows in the left operand of matrix-matrix multiplication.");
 }
 Matrix m = that.like();
 for (int col = 0; col < diagonal.size(); col++) {
  m.assignColumn(col, that.viewColumn(col).times(diagonal.getQuick(col)));
 }
 return m;
}

代码示例来源：origin: apache/mahout

@Override
public void setQuick(int index, double value) {
 Vector v = rowToColumn ? matrix.viewColumn(index) : matrix.viewRow(index);
 if (v == null) {
  v = newVector(numCols);
  if (rowToColumn) {
   matrix.assignColumn(index, v);
  } else {
   matrix.assignRow(index, v);
  }
 }
 v.setQuick(transposeOffset, value);
}

代码示例来源：origin: apache/mahout

@Test
public void testViewColumn() {
 Vector column = test.viewColumn(1);
 assertEquals("row size", 3, column.getNumNondefaultElements());
}

代码示例来源：origin: apache/mahout

@Test
public void testIterate() {
 Iterator<MatrixSlice> it = test.iterator();
 MatrixSlice m;
 while (it.hasNext() && (m = it.next()) != null) {
  Vector v = m.vector();
  Vector w = test instanceof SparseColumnMatrix ? test.viewColumn(m.index()) : test.viewRow(m.index());
  assertEquals("iterator: " + v + ", randomAccess: " + w, v, w);
 }
}

代码示例来源：origin: apache/mahout

@Test
public void testViewColumn() {
 Vector column = test.viewColumn(1);
 assertEquals("row size", 3, column.getNumNondefaultElements());
 int i = 0;
 for (double x : new double[]{3.3, 5.5, 7.7}) {
  assertEquals(x, column.get(i++), 0);
 }
}

代码示例来源：origin: apache/mahout

@Test
public void testAggregateCols() {
 Vector v = test.aggregateColumns(new VectorFunction() {
  @Override
  public double apply(Vector v) {
   return v.zSum();
  }
 });
 for (int i = 0; i < test.numCols(); i++) {
  assertEquals(test.viewColumn(i).zSum(), v.get(i), EPSILON);
 }
}

代码示例来源：origin: apache/mahout

@Test
public void testViewDenseSparseReporting() {
 Matrix m = new SparseMatrix(1000, 1000);
 m.set(1, 1, 33.0);
 Matrix mt = Matrices.transposedView(m);
 assertTrue(mt.viewColumn(0).isDense() == m.viewRow(0).isDense());
 assertTrue(mt.viewRow(0).isDense() == m.viewColumn(0).isDense());
 m = new DenseMatrix(10,10);
 m.set(1, 1, 33.0);
 mt = Matrices.transposedView(m);
 assertTrue(mt.viewColumn(0).isDense());
 assertTrue(mt.viewRow(0).isDense());
}

代码示例来源：origin: apache/mahout

/**
 * Test for the error reported in https://issues.apache.org/jira/browse/MAHOUT-1146
 */
@Test
public void testColumnView() {
 Matrix matrix = new DenseMatrix(5, 3);
 Vector column2 = matrix.viewColumn(2);
 Matrix outerProduct = column2.cross(column2);
 assertEquals(matrix.numRows(), outerProduct.numRows());
 assertEquals(matrix.numRows(), outerProduct.numCols());
}