cern.colt.matrix

## Class ObjectMatrix1D

- java.lang.Object
- - cern.colt.PersistentObject
  - - cern.colt.matrix.impl.AbstractMatrix
    - - cern.colt.matrix.impl.AbstractMatrix1D
      - - cern.colt.matrix.ObjectMatrix1D

All Implemented Interfaces:
  java.io.Serializable, java.lang.Cloneable

Direct Known Subclasses:
  DenseObjectMatrix1D, SparseObjectMatrix1D

    public abstract class ObjectMatrix1D
    extends AbstractMatrix1D

Abstract base class for 1-d matrices (aka vectors) holding `Object` elements. First see the package summary and javadoc tree view to get the broad picture.

A matrix has a number of cells (its size), which are assigned upon instance construction. Elements are accessed via zero based indexes. Legal indexes are of the form `[0..size()-1]`. Any attempt to access an element at a coordinate `index<0 || index>=size()` will throw an `IndexOutOfBoundsException`.

Version:
  1.0, 09/24/99
See Also:
  Serialized Form

### Field Summary

### Fields inherited from class cern.colt.PersistentObject

`serialVersionUID`

### Method Summary

Methods
`java.lang.Object` `aggregate(ObjectMatrix1D other, ObjectObjectFunction aggr, ObjectObjectFunction f)` Applies a function to each corresponding cell of two matrices and aggregates the results.
`java.lang.Object` `aggregate(ObjectObjectFunction aggr, ObjectFunction f)` Applies a function to each cell and aggregates the results.
`ObjectMatrix1D` `assign(java.lang.Object value)` Sets all cells to the state specified by `value`.
`ObjectMatrix1D` `assign(java.lang.Object[] values)` Sets all cells to the state specified by `values`.
`ObjectMatrix1D` `assign(ObjectFunction function)` Assigns the result of a function to each cell; `x[i] = function(x[i])`.
`ObjectMatrix1D` `assign(ObjectMatrix1D other)` Replaces all cell values of the receiver with the values of another matrix.
`ObjectMatrix1D` `assign(ObjectMatrix1D y, ObjectObjectFunction function)` Assigns the result of a function to each cell; `x[i] = function(x[i],y[i])`.
`int` `cardinality()` Returns the number of cells having non-zero values; ignores tolerance.
`ObjectMatrix1D` `copy()` Constructs and returns a deep copy of the receiver.
`boolean` `equals(java.lang.Object otherObj)` Compares the specified Object with the receiver for equality.
`boolean` `equals(java.lang.Object otherObj, boolean testForEquality)` Compares the specified Object with the receiver for equality.
`java.lang.Object` `get(int index)` Returns the matrix cell value at coordinate `index`.
`void` `getNonZeros(IntArrayList indexList, ObjectArrayList valueList)` Fills the coordinates and values of cells having non-zero values into the specified lists.
`abstract java.lang.Object` `getQuick(int index)` Returns the matrix cell value at coordinate `index`.
`ObjectMatrix1D` `like()` Construct and returns a new empty matrix of the same dynamic type as the receiver, having the same size.
`abstract ObjectMatrix1D` `like(int size)` Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified size.
`abstract ObjectMatrix2D` `like2D(int rows, int columns)` Construct and returns a new 2-d matrix of the corresponding dynamic type, entirelly independent of the receiver.
`void` `set(int index, java.lang.Object value)` Sets the matrix cell at coordinate `index` to the specified value.
`abstract void` `setQuick(int index, java.lang.Object value)` Sets the matrix cell at coordinate `index` to the specified value.
`void` `swap(ObjectMatrix1D other)` Swaps each element `this[i]` with `other[i]`.
`java.lang.Object[]` `toArray()` Constructs and returns a 1-dimensional array containing the cell values.
`void` `toArray(java.lang.Object[] values)` Fills the cell values into the specified 1-dimensional array.
`java.lang.String` `toString()` Returns a string representation using default formatting.
`ObjectMatrix1D` `viewFlip()` Constructs and returns a new flip view.
`ObjectMatrix1D` `viewPart(int index, int width)` Constructs and returns a new sub-range view that is a `width` sub matrix starting at `index`.
`ObjectMatrix1D` `viewSelection(int[] indexes)` Constructs and returns a new selection view that is a matrix holding the indicated cells.
`ObjectMatrix1D` `viewSelection(ObjectProcedure condition)` Constructs and returns a new selection view that is a matrix holding the cells matching the given condition.
`ObjectMatrix1D` `viewSorted()` Sorts the vector into ascending order, according to the natural ordering.
`ObjectMatrix1D` `viewStrides(int stride)` Constructs and returns a new stride view which is a sub matrix consisting of every i-th cell.

### Methods inherited from class cern.colt.matrix.impl.AbstractMatrix1D

`checkSize, size, toStringShort`

### Methods inherited from class cern.colt.matrix.impl.AbstractMatrix

`ensureCapacity, trimToSize`

### Methods inherited from class cern.colt.PersistentObject

`clone`

### Methods inherited from class java.lang.Object

`getClass, hashCode, notify, notifyAll, wait, wait, wait`

### Method Detail

#### aggregate

    public java.lang.Object aggregate(ObjectObjectFunction aggr,
                             ObjectFunction f)

Applies a function to each cell and aggregates the results. Returns a value `v` such that `v==a(size())` where `a(i) == aggr( a(i-1), f(get(i)) )` and terminators are `a(1) == f(get(0)), a(0)==null`.

Example:

    cern.jet.math.Functions F = cern.jet.math.Functions.functions;
    matrix = 0 1 2 3

    // Sum( x[i]*x[i] )
    matrix.aggregate(F.plus,F.square);
    --> 14

For further examples, see the package doc.

Parameters:
  `aggr` - an aggregation function taking as first argument the current aggregation and as second argument the transformed current cell value.
  `f` - a function transforming the current cell value.
Returns:
  the aggregated measure.

#### aggregate

    public java.lang.Object aggregate(ObjectMatrix1D other,
                             ObjectObjectFunction aggr,
                             ObjectObjectFunction f)

Applies a function to each corresponding cell of two matrices and aggregates the results. Returns a value `v` such that `v==a(size())` where `a(i) == aggr( a(i-1), f(get(i),other.get(i)) )` and terminators are `a(1) == f(get(0),other.get(0)), a(0)==null`.

Example:

    cern.jet.math.Functions F = cern.jet.math.Functions.functions;
    x = 0 1 2 3
    y = 0 1 2 3

    // Sum( x[i]*y[i] )
    x.aggregate(y, F.plus, F.mult);
    --> 14

    // Sum( (x[i]+y[i])^2 )
    x.aggregate(y, F.plus, F.chain(F.square,F.plus));
    --> 56

For further examples, see the package doc.

Parameters:
  `aggr` - an aggregation function taking as first argument the current aggregation and as second argument the transformed current cell values.
  `f` - a function transforming the current cell values.
Returns:
  the aggregated measure.
Throws:
  `java.lang.IllegalArgumentException` - if `size() != other.size()`.

#### assign

    public ObjectMatrix1D assign(java.lang.Object[] 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.

Parameters:
  `values` - the values to be filled into the cells.
Returns:
  `this` (for convenience only).
Throws:
  `java.lang.IllegalArgumentException` - if `values.length != size()`.

#### assign

    public ObjectMatrix1D assign(ObjectFunction 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.

Parameters:
  `function` - a function object taking as argument the current cell's value.
Returns:
  `this` (for convenience only).
See Also:
  `Functions`

#### assign

    public ObjectMatrix1D assign(ObjectMatrix1D other)

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`.

Parameters:
  `other` - the source matrix to copy from (may be identical to the receiver).
Returns:
  `this` (for convenience only).
Throws:
  `java.lang.IllegalArgumentException` - if `size() != other.size()`.

#### assign

    public ObjectMatrix1D assign(ObjectMatrix1D y,
                        ObjectObjectFunction function)

Assigns the result of a function to each cell; `x[i] = function(x[i],y[i])`.

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 further examples, see the package doc.

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:
  `java.lang.IllegalArgumentException` - if `size() != y.size()`.
See Also:
  `Functions`

#### assign

    public ObjectMatrix1D assign(java.lang.Object value)

Sets all cells to the state specified by `value`.

Parameters:
  `value` - the value to be filled into the cells.
Returns:
  `this` (for convenience only).

#### cardinality

    public int cardinality()

Returns the number of cells having non-zero values; ignores tolerance.

#### copy

    public ObjectMatrix1D copy()

Constructs and returns a deep copy of the receiver.

Note that the returned matrix is an independent deep copy. The returned matrix is not backed by this matrix, so changes in the returned matrix are not reflected in this matrix, and vice-versa.

Returns:
  a deep copy of the receiver.

#### equals

    public boolean equals(java.lang.Object otherObj)

Compares the specified Object with the receiver for equality. Equivalent to `equals(otherObj,true)`.

Overrides:
  `equals` in class `java.lang.Object`
Parameters:
  `otherObj` - the Object to be compared for equality with the receiver.
Returns:
  true if the specified Object is equal to the receiver.

#### equals

    public boolean equals(java.lang.Object otherObj,
                 boolean testForEquality)

Compares the specified Object with the receiver for equality. Returns true if and only if the specified Object is also at least an ObjectMatrix1D, both matrices have the same size, and all corresponding pairs of cells in the two matrices are the same. In other words, two matrices are defined to be equal if they contain the same cell values in the same order. Tests elements for equality or identity as specified by `testForEquality`. When testing for equality, two elements `e1` and `e2` are equal if `(e1==null ? e2==null : e1.equals(e2))`.)

Parameters:
  `otherObj` - the Object to be compared for equality with the receiver.
  `testForEquality` - if true -> tests for equality, otherwise for identity.
Returns:
  true if the specified Object is equal to the receiver.

#### get

    public java.lang.Object get(int index)

Returns the matrix cell value at coordinate `index`.

Parameters:
  `index` - the index of the cell.
Returns:
  the value of the specified cell.
Throws:
  `java.lang.IndexOutOfBoundsException` - if `index<0 || index>=size()`.

#### getNonZeros

    public void getNonZeros(IntArrayList indexList,
                   ObjectArrayList valueList)

Fills the coordinates and values of cells having non-zero values into the specified lists. Fills into the lists, starting at index 0. After this call returns the specified lists all have a new size, the number of non-zero values.

In general, fill order is unspecified. This implementation fills like: `for (index = 0..size()-1) do ...` . However, subclasses are free to us any other order, even an order that may change over time as cell values are changed. (Of course, result lists indexes are guaranteed to correspond to the same cell).

Example:

    0, 0, 8, 0, 7
    -->
    indexList  = (2,4)
    valueList  = (8,7)

In other words, `get(2)==8, get(4)==7`.

Parameters:
  `indexList` - the list to be filled with indexes, can have any size.
  `valueList` - the list to be filled with values, can have any size.

#### getQuick

    public abstract java.lang.Object 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()`.

Parameters:
  `index` - the index of the cell.
Returns:
  the value of the specified cell.

#### like

    public ObjectMatrix1D like()

Construct and returns a new empty matrix of the same dynamic type as the receiver, having the same size. For example, if the receiver is an instance of type `DenseObjectMatrix1D` the new matrix must also be of type `DenseObjectMatrix1D`, if the receiver is an instance of type `SparseObjectMatrix1D` the new matrix must also be of type `SparseObjectMatrix1D`, etc. In general, the new matrix should have internal parametrization as similar as possible.

Returns:
  a new empty matrix of the same dynamic type.

#### like

    public abstract ObjectMatrix1D 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 `DenseObjectMatrix1D` the new matrix must also be of type `DenseObjectMatrix1D`, if the receiver is an instance of type `SparseObjectMatrix1D` the new matrix must also be of type `SparseObjectMatrix1D`, etc. In general, the new matrix should have internal parametrization as similar as possible.

Parameters:
  `size` - the number of cell the matrix shall have.
Returns:
  a new empty matrix of the same dynamic type.

#### like2D

    public abstract ObjectMatrix2D 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 `DenseObjectMatrix1D` the new matrix must be of type `DenseObjectMatrix2D`, if the receiver is an instance of type `SparseObjectMatrix1D` the new matrix must be of type `SparseObjectMatrix2D`, etc.

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.

#### set

    public void set(int index,
           java.lang.Object value)

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

Parameters:
  `index` - the index of the cell.
  `value` - the value to be filled into the specified cell.
Throws:
  `java.lang.IndexOutOfBoundsException` - if `index<0 || index>=size()`.

#### setQuick

    public abstract void setQuick(int index,
                java.lang.Object 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()`.

Parameters:
  `index` - the index of the cell.
  `value` - the value to be filled into the specified cell.

#### swap

    public void swap(ObjectMatrix1D other)

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

Throws:
  `java.lang.IllegalArgumentException` - if `size() != other.size()`.

#### toArray

    public java.lang.Object[] toArray()

Constructs and returns a 1-dimensional array containing the cell values. The values are copied. So subsequent changes in `values` are not reflected in the matrix, and vice-versa. The returned array `values` has the form
`for (int i=0; i < size(); i++) values[i] = get(i);`

Returns:
  an array filled with the values of the cells.

#### toArray

    public void toArray(java.lang.Object[] 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);`

Throws:
  `java.lang.IllegalArgumentException` - if `values.length < size()`.

#### toString

    public java.lang.String toString()

Returns a string representation using default formatting.

Overrides:
  `toString` in class `java.lang.Object`
See Also:
  `Formatter`

#### viewFlip

    public ObjectMatrix1D viewFlip()

Constructs and returns a new flip view. What used to be index `0` is now index `size()-1`, ..., what used to be index `size()-1` is now index `0`. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa.

Returns:
  a new flip view.

#### viewPart

    public ObjectMatrix1D viewPart(int index,
                          int width)

Constructs and returns a new sub-range view that is a `width` sub matrix starting at `index`. Operations on the returned view can only be applied to the restricted range. Any attempt to access coordinates not contained in the view will throw an `IndexOutOfBoundsException`.

Note that the view is really just a range restriction: The returned matrix is backed by this matrix, so changes in the returned matrix are reflected in this matrix, and vice-versa.

The view contains the cells from `index..index+width-1`. and has `view.size() == width`. A view's legal coordinates are again zero based, as usual. In other words, legal coordinates of the view are `0 .. view.size()-1==width-1`. As usual, any attempt to access a cell at other coordinates will throw an `IndexOutOfBoundsException`.

Parameters:
  `index` - The index of the first cell.
  `width` - The width of the range.
Returns:
  the new view.
Throws:
  `java.lang.IndexOutOfBoundsException` - if `index<0 || width<0 || index+width>size()`.

#### viewSelection

    public ObjectMatrix1D viewSelection(int[] indexes)

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.

Parameters:
  `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`.
Returns:
  the new view.
Throws:
  `java.lang.IndexOutOfBoundsException` - if `!(0 <= indexes[i] < size())` for any `i=0..indexes.length()-1`.

#### viewSelection

    public ObjectMatrix1D viewSelection(ObjectProcedure condition)

Constructs and returns a new selection view that is a matrix holding the cells matching the given condition. Applies the condition to each cell and takes only those cells where `condition.apply(get(i))` yields `true`.

Example:

    // extract and view all cells with even value
    matrix = 0 1 2 3
    matrix.viewSelection(
       new ObjectProcedure() {
          public final boolean apply(Object a) { return a % 2 == 0; }
       }
    );
    -->
    matrix ==  0 2

For further examples, see the package doc. The returned view is backed by this matrix, so changes in the returned view are reflected in this matrix, and vice-versa.

Parameters:
  `condition` - The condition to be matched.
Returns:
  the new view.

#### viewSorted

    public ObjectMatrix1D viewSorted()

Sorts the vector into ascending order, according to the natural ordering. This sort is guaranteed to be stable. For further information, see `Sorting.sort(ObjectMatrix1D)`. For more advanced sorting functionality, see `Sorting`.

Returns:
  a new sorted vector (matrix) view.

#### viewStrides

    public ObjectMatrix1D viewStrides(int stride)

Constructs and returns a new stride view which is a sub matrix consisting of every i-th cell. More specifically, the view has size `this.size()/stride` holding cells `this.get(i*stride)` for all `i = 0..size()/stride - 1`.

Parameters:
  `stride` - the step factor.
Returns:
  the new view.
Throws:
  `java.lang.IndexOutOfBoundsException` - if `stride <= 0`.