cern.colt.matrix.tlong.impl

Class SparseLongMatrix1D

java.lang.Object

cern.colt.PersistentObject

cern.colt.matrix.AbstractMatrix

cern.colt.matrix.AbstractMatrix1D

cern.colt.matrix.tlong.LongMatrix1D

cern.colt.matrix.tlong.impl.SparseLongMatrix1D

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class SparseLongMatrix1D
extends LongMatrix1D

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

Implementation:

Note that this implementation is not synchronized. Uses a OpenIntLongHashMap, which is a compact and performant hashing technique.

Memory requirements:

Cells that

• are never set to non-zero values do not use any memory.
• switch from zero to non-zero state do use memory.
• switch back from non-zero to zero state also do use memory. However, their memory is automatically reclaimed from time to time. It can also manually be reclaimed by calling trimToSize().

worst case: memory [bytes] = (1/minLoadFactor) * nonZeros * 13.
best case: memory [bytes] = (1/maxLoadFactor) * nonZeros * 13.
Where nonZeros = cardinality() is the number of non-zero cells. Thus, a 1000000 matrix with minLoadFactor=0.25 and maxLoadFactor=0.5 and 1000000 non-zero cells consumes between 25 MB and 50 MB. The same 1000000 matrix with 1000 non-zero cells consumes between 25 and 50 KB.

Time complexity:

This class offers expected time complexity O(1) (i.e. constant time) for the basic operations get, getQuick, set, setQuick and size assuming the hash function disperses the elements properly among the buckets. Otherwise, pathological cases, although highly improbable, can occur, degrading performance to O(N) in the worst case. As such this sparse class is expected to have no worse time complexity than its dense counterpart DenseLongMatrix1D. However, constant factors are considerably larger.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SparseLongMatrix1D(int size) Constructs a matrix with a given number of cells.
SparseLongMatrix1D(int size, int initialCapacity, double minLoadFactor, double maxLoadFactor) Constructs a matrix with a given number of parameters.
SparseLongMatrix1D(long[] values) Constructs a matrix with a copy of the given values.

Method Summary

Modifier and Type	Method and Description
LongMatrix1D	assign(long value) Sets all cells to the state specified by value.
int	cardinality() Returns the number of cells having non-zero values.
AbstractLongLongMap	elements() Returns the elements of this matrix.
void	ensureCapacity(int minCapacity) Ensures that the receiver can hold at least the specified number of non-zero cells without needing to allocate new internal memory.
long	getQuick(int index) Returns the matrix cell value at coordinate index.
long	index(int rank) Returns the position of the element with the given relative rank within the (virtual or non-virtual) internal 1-dimensional array.
LongMatrix1D	like(int size) Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified size.
LongMatrix2D	like2D(int rows, int columns) Construct and returns a new 2-d matrix of the corresponding dynamic type, entirelly independent of the receiver.
LongMatrix2D	reshape(int rows, int columns) Returns new LongMatrix2D of size rows x columns whose elements are taken column-wise from this matrix.
LongMatrix3D	reshape(int slices, int rows, int columns) Returns new LongMatrix3D of size slices x rows x columns, whose elements are taken column-wise from this matrix.
void	setQuick(int index, long value) Sets the matrix cell at coordinate index to the specified value.
java.lang.String	toString() Returns a string representation using default formatting.
void	trimToSize() Releases any superfluous internal memory.

Methods inherited from class cern.colt.matrix.tlong.LongMatrix1D

aggregate, aggregate, aggregate, assign, assign, assign, assign, assign, assign, assign, assign, copy, equals, equals, get, getMaxLocation, getMinLocation, getNegativeValues, getNonZeros, getNonZeros, getPositiveValues, like, set, setSize, swap, toArray, toArray, viewFlip, viewPart, viewSelection, viewSelection, viewSorted, viewStrides, zDotProduct, zDotProduct, zDotProduct, zSum

Methods inherited from class cern.colt.matrix.AbstractMatrix1D

checkSize, size, stride, toStringShort

Methods inherited from class cern.colt.matrix.AbstractMatrix

isView

Methods inherited from class cern.colt.PersistentObject

clone

Methods inherited from class java.lang.Object

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

Constructor Detail

SparseLongMatrix1D

public SparseLongMatrix1D(long[] 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.

SparseLongMatrix1D

public SparseLongMatrix1D(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:

java.lang.IllegalArgumentException - if size<0.

SparseLongMatrix1D

public SparseLongMatrix1D(int size,
                          int initialCapacity,
                          double minLoadFactor,
                          double maxLoadFactor)

Constructs a matrix with a given number of parameters. All entries are initially 0. For details related to memory usage see OpenIntLongHashMap.

Parameters:

size - the number of cells the matrix shall have.

initialCapacity - the initial capacity of the hash map. If not known, set initialCapacity=0 or small.

minLoadFactor - the minimum load factor of the hash map.

maxLoadFactor - the maximum load factor of the hash map.

Throws:

java.lang.IllegalArgumentException - if initialCapacity < 0 || (minLoadFactor < 0.0 || minLoadFactor >= 1.0) || (maxLoadFactor <= 0.0 || maxLoadFactor >= 1.0) || (minLoadFactor >= maxLoadFactor) .

java.lang.IllegalArgumentException - if size<0.

Method Detail

assign

public LongMatrix1D assign(long value)

Sets all cells to the state specified by value.

Overrides:

assign in class LongMatrix1D

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.

Overrides:

cardinality in class LongMatrix1D

Returns:

the number of cells having non-zero values.

elements

public AbstractLongLongMap elements()

Returns the elements of this matrix.

Specified by:

elements in class LongMatrix1D

Returns:

the elements

ensureCapacity

public void ensureCapacity(int minCapacity)

Ensures that the receiver can hold at least the specified number of non-zero cells without needing to allocate new internal memory. If necessary, allocates new internal memory and increases the capacity of the receiver.

This method never need be called; it is for performance tuning only. Calling this method before tt>set()ing a large number of non-zero values boosts performance, because the receiver will grow only once instead of potentially many times and hash collisions get less probable.

Overrides:

ensureCapacity in class AbstractMatrix

Parameters:

minCapacity - the desired minimum number of non-zero cells.

getQuick

public long 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 LongMatrix1D

Parameters:

index - the index of the cell.

Returns:

the value of the specified cell.

index

public long index(int rank)

Returns the position of the element with the given relative rank within the (virtual or non-virtual) internal 1-dimensional array. You may want to override this method for performance.

Overrides:

index in class AbstractMatrix1D

Parameters:

rank - the rank of the element.

like

public LongMatrix1D 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 DenseLongMatrix1D the new matrix must also be of type DenseLongMatrix1D, if the receiver is an instance of type SparseLongMatrix1D the new matrix must also be of type SparseLongMatrix1D, etc. In general, the new matrix should have internal parametrization as similar as possible.

Specified by:

like in class LongMatrix1D

Parameters:

size - the number of cell the matrix shall have.

Returns:

a new empty matrix of the same dynamic type.

like2D

public LongMatrix2D 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 DenseLongMatrix1D the new matrix must be of type DenseLongMatrix2D, if the receiver is an instance of type SparseLongMatrix1D the new matrix must be of type SparseLongMatrix2D, etc.

Specified by:

like2D in class LongMatrix1D

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.

reshape

public LongMatrix2D reshape(int rows,
                            int columns)

Description copied from class: LongMatrix1D

Returns new LongMatrix2D of size rows x columns whose elements are taken column-wise from this matrix.

Specified by:

reshape in class LongMatrix1D

Parameters:

rows - number of rows

columns - number of columns

Returns:

new 2D matrix with columns being the elements of this matrix.

reshape

public LongMatrix3D reshape(int slices,
                            int rows,
                            int columns)

Description copied from class: LongMatrix1D

Returns new LongMatrix3D of size slices x rows x columns, whose elements are taken column-wise from this matrix.

Specified by:

reshape in class LongMatrix1D

rows - number of rows

columns - number of columns

Returns:

new 2D matrix with columns being the elements of this matrix.

setQuick

public void setQuick(int index,
                     long 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 LongMatrix1D

Parameters:

index - the index of the cell.

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

toString

public java.lang.String toString()

Description copied from class: LongMatrix1D

Returns a string representation using default formatting.

Overrides:

toString in class LongMatrix1D

See Also:

LongFormatter

trimToSize

public void trimToSize()

Description copied from class: AbstractMatrix

Releases any superfluous internal memory. An application can use this operation to minimize the storage of the receiver.

This default implementation does nothing. Override this method if necessary.

Overrides:

trimToSize in class AbstractMatrix