public class SparseDoubleMatrix1D extends DoubleMatrix1D
Implementation:
Note that this implementation is not synchronized.
Uses a OpenIntDoubleHashMap, which is a compact and performant hashing technique.
Memory requirements:
Cells that
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.
| Modifier and Type | Field and Description |
|---|---|
protected AbstractIntDoubleMap |
elements |
size, stride, zeroisNoViewserialVersionUID| Modifier | Constructor and 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.
|
protected |
SparseDoubleMatrix1D(int size,
AbstractIntDoubleMap elements,
int offset,
int stride)
Constructs a matrix view with a given number of parameters.
|
|
SparseDoubleMatrix1D(int size,
int initialCapacity,
double minLoadFactor,
double maxLoadFactor)
Constructs a matrix with a given number of parameters.
|
| Modifier and Type | Method and 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.
|
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_offset, _rank, checkIndex, checkIndexes, checkRange, checkSize, checkSize, setUp, setUp, size, stride, toStringShort, vFlip, vPart, vStridesisViewcloneprotected AbstractIntDoubleMap elements
public SparseDoubleMatrix1D(double[] values)
values - The values to be filled into the new matrix.public SparseDoubleMatrix1D(int size)
size - the number of cells the matrix shall have.IllegalArgumentException - if size<0.public SparseDoubleMatrix1D(int size,
int initialCapacity,
double minLoadFactor,
double maxLoadFactor)
OpenIntDoubleHashMap.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.IllegalArgumentException - if initialCapacity < 0 || (minLoadFactor < 0.0 || minLoadFactor >= 1.0) || (maxLoadFactor <= 0.0 || maxLoadFactor >= 1.0) || (minLoadFactor >= maxLoadFactor).IllegalArgumentException - if size<0.protected SparseDoubleMatrix1D(int size,
AbstractIntDoubleMap elements,
int offset,
int stride)
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).IllegalArgumentException - if size<0.public DoubleMatrix1D assign(double value)
assign in class DoubleMatrix1Dvalue - the value to be filled into the cells.public int cardinality()
cardinality in class DoubleMatrix1Dpublic void ensureCapacity(int minCapacity)
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.
ensureCapacity in class AbstractMatrixminNonZeros - the desired minimum number of non-zero cells.public double getQuick(int 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().
getQuick in class DoubleMatrix1Dindex - the index of the cell.protected boolean haveSharedCellsRaw(DoubleMatrix1D other)
haveSharedCellsRaw in class DoubleMatrix1Dprotected int index(int rank)
index in class AbstractMatrix1Drank - the rank of the element.public DoubleMatrix1D like(int size)
like in class DoubleMatrix1Dsize - the number of cell the matrix shall have.public DoubleMatrix2D like2D(int rows, int columns)
like2D in class DoubleMatrix1Drows - the number of rows the matrix shall have.columns - the number of columns the matrix shall have.public void setQuick(int index,
double 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().
setQuick in class DoubleMatrix1Dindex - the index of the cell.value - the value to be filled into the specified cell.public void trimToSize()
Background:
Cells that
trimToSize in class AbstractMatrixprotected DoubleMatrix1D viewSelectionLike(int[] offsets)
viewSelectionLike in class DoubleMatrix1Doffsets - the offsets of the visible elements.Copyright © 2006–2019 SYSTAP, LLC DBA Blazegraph. All rights reserved.