Examples of cern.colt.matrix.DoubleMatrix1D.viewSelection()

cern.colt.matrix.DoubleMatrix1D.viewSelection()

Constructs and returns a new selection view that is a matrix holding the indicated cells. There holds view.size() == indexes.length and view.get(i) == this.get(indexes[i]). Indexes can occur multiple times and can be in arbitrary order.

Example:

 this     = (0,0,8,0,7) indexes  = (0,2,4,2) --> view     = (0,8,7,8)

Note that modifying indexes after this call has returned has no effect on the view. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa. @param indexes The indexes of the cells that shall be visible in the new view. To indicate that all cells shall be visible, simply set this parameter to null. @return the new view. @throws IndexOutOfBoundsException if !(0 <= indexes[i] < size()) for any i=0..indexes.length()-1.

double[] values = {0, 1, 2, 3};
DoubleMatrix1D matrix = new DenseDoubleMatrix1D(values);
System.out.println(matrix);


// Sum( x[i]*x[i] ) 
System.out.println(matrix.viewSelection(
  new cern.colt.function.DoubleProcedure() {
    public final boolean apply(double a) { return a % 2 == 0; }
  }
));
//--> 14

double[] values = {0, 1, 2, 3};
DoubleMatrix1D matrix = new DenseDoubleMatrix1D(values);
System.out.println(matrix);


// Sum( x[i]*x[i] ) 
System.out.println(matrix.viewSelection(
  new cern.colt.function.DoubleProcedure() {
    public final boolean apply(double a) { return a % 2 == 0; }
  }
));
//--> 14

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