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java.lang.Object cern.colt.PersistentObject cern.colt.matrix.impl.AbstractMatrix cern.colt.matrix.impl.AbstractMatrix1D cern.colt.matrix.DoubleMatrix1D cern.colt.matrix.impl.SparseDoubleMatrix1D
Sparse hashed 1d 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
trimToSize()
.
worst case: memory [bytes] = (1/minLoadFactor) * nonZeros * 13.
best case: memory [bytes] = (1/maxLoadFactor) * nonZeros * 13.
Where nonZeros = cardinality() is the number of nonzero cells.
Thus, a 1000000 matrix with minLoadFactor=0.25 and maxLoadFactor=0.5 and 1000000 nonzero cells consumes between 25 MB and 50 MB.
The same 1000000 matrix with 1000 nonzero 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.
Field Summary 
Fields inherited from class cern.colt.PersistentObject 
serialVersionUID 
Constructor Summary  
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. 
Method Summary  
DoubleMatrix1D 
assign(double value)
Sets all cells to the state specified by value. 
int 
cardinality()
Returns the number of cells having nonzero values. 
void 
ensureCapacity(int minCapacity)
Ensures that the receiver can hold at least the specified number of nonzero cells without needing to allocate new internal memory. 
double 
getQuick(int index)
Returns the matrix cell value at coordinate index. 
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 2d 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 nonzero values; An application can use this operation to minimize the storage of the receiver. 
Methods inherited from class cern.colt.matrix.DoubleMatrix1D 
aggregate, aggregate, assign, assign, assign, assign, assign, copy, equals, equals, get, getNonZeros, getNonZeros, like, set, swap, toArray, toArray, toString, viewFlip, viewPart, viewSelection, viewSelection, viewSorted, viewStrides, zDotProduct, zDotProduct, zDotProduct, zSum 
Methods inherited from class cern.colt.matrix.impl.AbstractMatrix1D 
checkSize, size, toStringShort 
Methods inherited from class cern.colt.PersistentObject 
clone 
Methods inherited from class java.lang.Object 
getClass, hashCode, notify, notifyAll, wait, wait, wait 
Constructor Detail 
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.Method Detail 
public DoubleMatrix1D assign(double value)
assign
in class DoubleMatrix1D
value
 the value to be filled into the cells.
public int cardinality()
cardinality
in class DoubleMatrix1D
public 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 nonzero values boosts performance, because the receiver will grow only once instead of potentially many times and hash collisions get less probable.
ensureCapacity
in class AbstractMatrix
minCapacity
 the desired minimum number of nonzero (nonnull) 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 DoubleMatrix1D
index
 the index of the cell.
public DoubleMatrix1D like(int size)
like
in class DoubleMatrix1D
size
 the number of cell the matrix shall have.
public DoubleMatrix2D like2D(int rows, int columns)
like2D
in class DoubleMatrix1D
rows
 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 DoubleMatrix1D
index
 the index of the cell.value
 the value to be filled into the specified cell.public void trimToSize()
Background:
Cells that
trimToSize
in class AbstractMatrix

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