Class SparseDoubleMatrix1D
- java.lang.Object
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- cern.colt.PersistentObject
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- cern.colt.matrix.impl.AbstractMatrix
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- cern.colt.matrix.impl.AbstractMatrix1D
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- cern.colt.matrix.DoubleMatrix1D
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- cern.colt.matrix.impl.SparseDoubleMatrix1D
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- All Implemented Interfaces:
java.io.Serializable
,java.lang.Cloneable
public class SparseDoubleMatrix1D extends DoubleMatrix1D
Sparse hashed 1-d matrix (aka vector) holding double 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
OpenIntDoubleHashMap
, 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
DenseDoubleMatrix1D
. However, constant factors are considerably larger.- Version:
- 1.0, 09/24/99
- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description protected AbstractIntDoubleMap
elements
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Fields inherited from class cern.colt.matrix.impl.AbstractMatrix1D
size, stride, zero
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Fields inherited from class cern.colt.matrix.impl.AbstractMatrix
isNoView
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Fields inherited from class cern.colt.PersistentObject
serialVersionUID
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Constructor Summary
Constructors Modifier Constructor Description SparseDoubleMatrix1D(double[] values)
Constructs a matrix with a copy of the given values.SparseDoubleMatrix1D(int size)
Constructs a matrix with a given number of cells.SparseDoubleMatrix1D(int size, int initialCapacity, double minLoadFactor, double maxLoadFactor)
Constructs a matrix with a given number of parameters.protected
SparseDoubleMatrix1D(int size, AbstractIntDoubleMap elements, int offset, int stride)
Constructs a matrix view with a given number of parameters.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description DoubleMatrix1D
assign(double value)
Sets all cells to the state specified by value.int
cardinality()
Returns the number of cells having non-zero values.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.double
getQuick(int index)
Returns the matrix cell value at coordinate index.protected boolean
haveSharedCellsRaw(DoubleMatrix1D other)
Returns true if both matrices share at least one identical cell.protected int
index(int rank)
Returns the position of the element with the given relative rank within the (virtual or non-virtual) internal 1-dimensional array.DoubleMatrix1D
like(int size)
Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified size.DoubleMatrix2D
like2D(int rows, int columns)
Construct and returns a new 2-d matrix of the corresponding dynamic type, entirelly independent of the receiver.void
setQuick(int index, double value)
Sets the matrix cell at coordinate index to the specified value.void
trimToSize()
Releases any superfluous memory created by explicitly putting zero values into cells formerly having non-zero values; An application can use this operation to minimize the storage of the receiver.protected DoubleMatrix1D
viewSelectionLike(int[] offsets)
Construct and returns a new selection view.-
Methods inherited from class cern.colt.matrix.DoubleMatrix1D
aggregate, aggregate, assign, assign, assign, assign, assign, cardinality, copy, equals, equals, get, getContent, getNonZeros, getNonZeros, haveSharedCells, like, set, swap, toArray, toArray, toString, view, viewFlip, viewPart, viewSelection, viewSelection, viewSorted, viewStrides, zDotProduct, zDotProduct, zDotProduct, zDotProduct, zSum
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Methods inherited from class cern.colt.matrix.impl.AbstractMatrix1D
_offset, _rank, checkIndex, checkIndexes, checkRange, checkSize, checkSize, setUp, setUp, size, stride, toStringShort, vFlip, vPart, vStrides
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Methods inherited from class cern.colt.matrix.impl.AbstractMatrix
isView
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Methods inherited from class cern.colt.PersistentObject
clone
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Field Detail
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elements
protected AbstractIntDoubleMap elements
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Constructor Detail
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SparseDoubleMatrix1D
public SparseDoubleMatrix1D(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.
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SparseDoubleMatrix1D
public SparseDoubleMatrix1D(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.
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SparseDoubleMatrix1D
public SparseDoubleMatrix1D(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 seeOpenIntDoubleHashMap
.- 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.
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SparseDoubleMatrix1D
protected SparseDoubleMatrix1D(int size, AbstractIntDoubleMap elements, int offset, int stride)
Constructs a matrix view with a given number of parameters.- Parameters:
size
- the number of cells the matrix shall have.elements
- the cells.offset
- the index of the first element.stride
- the number of indexes between any two elements, i.e. index(i+1)-index(i).- Throws:
java.lang.IllegalArgumentException
- if size<0.
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Method Detail
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assign
public DoubleMatrix1D assign(double value)
Sets all cells to the state specified by value.- Overrides:
assign
in classDoubleMatrix1D
- Parameters:
value
- the value to be filled into the cells.- Returns:
- this (for convenience only).
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cardinality
public int cardinality()
Returns the number of cells having non-zero values.- Overrides:
cardinality
in classDoubleMatrix1D
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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 classAbstractMatrix
- Parameters:
minNonZeros
- the desired minimum number of non-zero cells.
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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 classDoubleMatrix1D
- Parameters:
index
- the index of the cell.- Returns:
- the value of the specified cell.
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haveSharedCellsRaw
protected boolean haveSharedCellsRaw(DoubleMatrix1D other)
Returns true if both matrices share at least one identical cell.- Overrides:
haveSharedCellsRaw
in classDoubleMatrix1D
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index
protected int 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 classAbstractMatrix1D
- Parameters:
rank
- the rank of the element.
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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 classDoubleMatrix1D
- Parameters:
size
- the number of cell the matrix shall have.- Returns:
- a new empty matrix of the same dynamic type.
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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 classDoubleMatrix1D
- 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.
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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 classDoubleMatrix1D
- Parameters:
index
- the index of the cell.value
- the value to be filled into the specified cell.
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trimToSize
public void trimToSize()
Releases any superfluous memory created by explicitly putting zero values into cells formerly having non-zero values; An application can use this operation to minimize the storage of the receiver.Background:
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 can be reclaimed by calling trimToSize().
- Overrides:
trimToSize
in classAbstractMatrix
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viewSelectionLike
protected DoubleMatrix1D viewSelectionLike(int[] offsets)
Construct and returns a new selection view.- Specified by:
viewSelectionLike
in classDoubleMatrix1D
- Parameters:
offsets
- the offsets of the visible elements.- Returns:
- a new view.
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