cern.colt.matrix.impl
Class DenseDoubleMatrix1D

java.lang.Object
  cern.colt.PersistentObject
      cern.colt.matrix.impl.AbstractMatrix
          cern.colt.matrix.impl.AbstractMatrix1D
              cern.colt.matrix.DoubleMatrix1D
                  cern.colt.matrix.impl.DenseDoubleMatrix1D

All Implemented Interfaces:

Cloneable, Serializable

public class DenseDoubleMatrix1D

extends DoubleMatrix1D

Dense 1-d matrix (aka vector) holding double elements. First see the package summary and javadoc tree view to get the broad picture.

Implementation:

Internally holds one single contigous one-dimensional array. Note that this implementation is not synchronized.

Memory requirements:

memory [bytes] = 8*size(). Thus, a 1000000 matrix uses 8 MB.

Time complexity:

O(1) (i.e. constant time) for the basic operations get, getQuick, set, setQuick and size,

Version:

1.0, 09/24/99

See Also:

Serialized Form

DenseDoubleMatrix1D

public DenseDoubleMatrix1D(double[] values)

Constructs a matrix with a copy of the given values. The values are copied. So subsequent changes in values are not reflected in the matrix, and vice-versa.

Parameters:

values - The values to be filled into the new matrix.

DenseDoubleMatrix1D

public DenseDoubleMatrix1D(int size)

Constructs a matrix with a given number of cells. All entries are initially 0.

Parameters:

size - the number of cells the matrix shall have.

Throws:

IllegalArgumentException - if size<0.

assign

public DoubleMatrix1D assign(double[] values)

Sets all cells to the state specified by values. values is required to have the same number of cells as the receiver.

The values are copied. So subsequent changes in values are not reflected in the matrix, and vice-versa.

Overrides:

assign in class DoubleMatrix1D

Parameters:

values - the values to be filled into the cells.

Returns:

this (for convenience only).

Throws:

IllegalArgumentException - if values.length != size().

assign

public DoubleMatrix1D assign(double value)

Sets all cells to the state specified by value.

Overrides:

assign in class DoubleMatrix1D

Parameters:

value - the value to be filled into the cells.

Returns:

this (for convenience only).

assign

public DoubleMatrix1D assign(DoubleFunction function)

Assigns the result of a function to each cell; x[i] = function(x[i]). (Iterates downwards from [size()-1] to [0]).

Example:

// change each cell to its sine
matrix =   0.5      1.5      2.5       3.5 
matrix.assign(cern.jet.math.Functions.sin);
-->
matrix ==  0.479426 0.997495 0.598472 -0.350783

For further examples, see the package doc.

Overrides:

assign in class DoubleMatrix1D

Parameters:

function - a function object taking as argument the current cell's value.

Returns:

this (for convenience only).

See Also:

Functions

assign

public DoubleMatrix1D assign(DoubleMatrix1D source)

Replaces all cell values of the receiver with the values of another matrix. Both matrices must have the same size. If both matrices share the same cells (as is the case if they are views derived from the same matrix) and intersect in an ambiguous way, then replaces as if using an intermediate auxiliary deep copy of other.

Overrides:

assign in class DoubleMatrix1D

Parameters:

source - the source matrix to copy from (may be identical to the receiver).

Returns:

this (for convenience only).

Throws:

IllegalArgumentException - if size() != other.size().

assign

public DoubleMatrix1D assign(DoubleMatrix1D y,
                             DoubleDoubleFunction function)

Assigns the result of a function to each cell; x[i] = function(x[i],y[i]). (Iterates downwards from [size()-1] to [0]).

Example:

// assign x[i] = x[i]y[i]
m1 = 0 1 2 3;
m2 = 0 2 4 6;
m1.assign(m2, cern.jet.math.Functions.pow);
-->
m1 == 1 1 16 729

// for non-standard functions there is no shortcut: 
m1.assign(m2,
   new DoubleDoubleFunction() {
      public double apply(double x, double y) { return Math.pow(x,y); }
   }
);

For further examples, see the package doc.

Overrides:

assign in class DoubleMatrix1D

Parameters:

y - the secondary matrix to operate on.

function - a function object taking as first argument the current cell's value of this, and as second argument the current cell's value of y,

Returns:

this (for convenience only).

Throws:

IllegalArgumentException - if size() != y.size().

See Also:

Functions

getQuick

public double getQuick(int index)

Returns the matrix cell value at coordinate index.

Provided with invalid parameters this method may return invalid objects without throwing any exception. You should only use this method when you are absolutely sure that the coordinate is within bounds. Precondition (unchecked): index<0 || index>=size().

Specified by:

getQuick in class DoubleMatrix1D

Parameters:

index - the index of the cell.

Returns:

the value of the specified cell.

like

public DoubleMatrix1D like(int size)

Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified size. For example, if the receiver is an instance of type DenseDoubleMatrix1D the new matrix must also be of type DenseDoubleMatrix1D, if the receiver is an instance of type SparseDoubleMatrix1D the new matrix must also be of type SparseDoubleMatrix1D, etc. In general, the new matrix should have internal parametrization as similar as possible.

Specified by:

like in class DoubleMatrix1D

Parameters:

size - the number of cell the matrix shall have.

Returns:

a new empty matrix of the same dynamic type.

like2D

public DoubleMatrix2D like2D(int rows,
                             int columns)

Construct and returns a new 2-d matrix of the corresponding dynamic type, entirelly independent of the receiver. For example, if the receiver is an instance of type DenseDoubleMatrix1D the new matrix must be of type DenseDoubleMatrix2D, if the receiver is an instance of type SparseDoubleMatrix1D the new matrix must be of type SparseDoubleMatrix2D, etc.

Specified by:

like2D in class DoubleMatrix1D

Parameters:

rows - the number of rows the matrix shall have.

columns - the number of columns the matrix shall have.

Returns:

a new matrix of the corresponding dynamic type.

setQuick

public void setQuick(int index,
                     double value)

Sets the matrix cell at coordinate index to the specified value.

Provided with invalid parameters this method may access illegal indexes without throwing any exception. You should only use this method when you are absolutely sure that the coordinate is within bounds. Precondition (unchecked): index<0 || index>=size().

Specified by:

setQuick in class DoubleMatrix1D

Parameters:

index - the index of the cell.

value - the value to be filled into the specified cell.

swap

public void swap(DoubleMatrix1D other)

Swaps each element this[i] with other[i].

Overrides:

swap in class DoubleMatrix1D

Throws:

IllegalArgumentException - if size() != other.size().

toArray

public void toArray(double[] values)

Fills the cell values into the specified 1-dimensional array. The values are copied. So subsequent changes in values are not reflected in the matrix, and vice-versa. After this call returns the array values has the form
for (int i=0; i < size(); i++) values[i] = get(i);

Overrides:

toArray in class DoubleMatrix1D

Throws:

IllegalArgumentException - if values.length < size().

zDotProduct

public double zDotProduct(DoubleMatrix1D y,
                          int from,
                          int length)

Returns the dot product of two vectors x and y, which is Sum(x[i]*y[i]). Where x == this. Operates on cells at indexes from .. Min(size(),y.size(),from+length)-1.

Overrides:

zDotProduct in class DoubleMatrix1D

Parameters:

y - the second vector.

from - the first index to be considered.

length - the number of cells to be considered.

Returns:

the sum of products; zero if from<0 || length<0.

zSum

public double zSum()

Returns the sum of all cells; Sum( x[i] ).

Overrides:

zSum in class DoubleMatrix1D

Returns:

the sum.