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java.lang.Object cern.colt.PersistentObject cern.colt.matrix.AbstractMatrix cern.colt.matrix.AbstractMatrix2D cern.colt.matrix.tfloat.FloatMatrix2D cern.colt.matrix.tfloat.impl.SparseFloatMatrix2D
public class SparseFloatMatrix2D
Sparse hashed 2-d matrix holding float 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
OpenIntFloatHashMap
, 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 1000 x 1000 matrix with minLoadFactor=0.25 and maxLoadFactor=0.5 and
1000000 non-zero cells consumes between 25 MB and 50 MB. The same 1000 x 1000
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
DenseFloatMatrix2D
. However, constant factors are considerably
larger.
Cells are internally addressed in row-major. Performance sensitive applications can exploit this fact. Setting values in a loop row-by-row is quicker than column-by-column, because fewer hash collisions occur. Thus
for (int row = 0; row < rows; row++) { for (int column = 0; column < columns; column++) { matrix.setQuick(row, column, someValue); } }is quicker than
for (int column = 0; column < columns; column++) { for (int row = 0; row < rows; row++) { matrix.setQuick(row, column, someValue); } }
cern.colt.map
,
OpenIntFloatHashMap
,
Serialized FormField Summary |
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Fields inherited from class cern.colt.PersistentObject |
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serialVersionUID |
Constructor Summary | |
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SparseFloatMatrix2D(float[][] values)
Constructs a matrix with a copy of the given values. |
|
SparseFloatMatrix2D(int rows,
int columns)
Constructs a matrix with a given number of rows and columns and default memory usage. |
|
SparseFloatMatrix2D(int rows,
int columns,
int[] rowIndexes,
int[] columnIndexes,
float value)
Constructs a matrix with a copy of the given indexes and value. |
|
SparseFloatMatrix2D(int rows,
int columns,
int[] rowIndexes,
int[] columnIndexes,
float[] values)
Constructs a matrix with a copy of the given indexes and values. |
|
SparseFloatMatrix2D(int rows,
int columns,
int initialCapacity,
float minLoadFactor,
float maxLoadFactor)
Constructs a matrix with a given number of rows and columns using memory as specified. |
|
SparseFloatMatrix2D(MatrixVectorReader r)
Constructs a matrix from MatrixVectorReader. |
Method Summary | |
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FloatMatrix2D |
assign(float value)
Sets all cells to the state specified by value. |
FloatMatrix2D |
assign(FloatFunction function)
Assigns the result of a function to each cell; x[row,col] = function(x[row,col]). |
FloatMatrix2D |
assign(FloatMatrix2D source)
Replaces all cell values of the receiver with the values of another matrix. |
FloatMatrix2D |
assign(FloatMatrix2D y,
FloatFloatFunction function)
Assigns the result of a function to each cell; x[row,col] = function(x[row,col],y[row,col]). |
SparseFloatMatrix2D |
assign(int[] rowIndexes,
int[] columnIndexes,
float[] values,
FloatFloatFunction function)
|
SparseFloatMatrix2D |
assign(int[] rowIndexes,
int[] columnIndexes,
float value,
FloatFloatFunction function)
|
int |
cardinality()
Returns the number of cells having non-zero values. |
CCFloatMatrix2D |
convertToCCFloatMatrix2D()
|
CCMFloatMatrix2D |
convertToCCMFloatMatrix2D()
|
RCFloatMatrix2D |
convertToRCFloatMatrix2D()
|
RCMFloatMatrix2D |
convertToRCMFloatMatrix2D()
|
AbstractLongFloatMap |
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. |
FloatMatrix2D |
forEachNonZero(IntIntFloatFunction function)
Assigns the result of a function to each non-zero cell; x[row,col] = function(x[row,col]). |
float |
getQuick(int row,
int column)
Returns the matrix cell value at coordinate [row,column]. |
long |
index(int row,
int column)
Returns the position of the given coordinate within the (virtual or non-virtual) internal 1-dimensional array. |
FloatMatrix2D |
like(int rows,
int columns)
Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified number of rows and columns. |
FloatMatrix1D |
like1D(int size)
Construct and returns a new 1-d matrix of the corresponding dynamic type, entirelly independent of the receiver. |
void |
setQuick(int row,
int column,
float value)
Sets the matrix cell at coordinate [row,column] 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. |
FloatMatrix1D |
vectorize()
Returns a vector obtained by stacking the columns of the matrix on top of one another. |
FloatMatrix1D |
zMult(FloatMatrix1D y,
FloatMatrix1D z,
float alpha,
float beta,
boolean transposeA)
Linear algebraic matrix-vector multiplication; z = alpha * A * y + beta*z. |
FloatMatrix2D |
zMult(FloatMatrix2D B,
FloatMatrix2D C,
float alpha,
float beta,
boolean transposeA,
boolean transposeB)
Linear algebraic matrix-matrix multiplication; C = alpha * A x B + beta*C. |
Methods inherited from class cern.colt.matrix.tfloat.FloatMatrix2D |
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aggregate, aggregate, aggregate, aggregate, assign, assign, assign, assign, assign, copy, equals, equals, get, getMaxLocation, getMinLocation, getNegativeValues, getNonZeros, getPositiveValues, like, normalize, set, toArray, toString, viewColumn, viewColumnFlip, viewDice, viewPart, viewRow, viewRowFlip, viewSelection, viewSelection, viewSelection, viewSorted, viewStrides, zAssign8Neighbors, zMult, zMult, zSum |
Methods inherited from class cern.colt.matrix.AbstractMatrix2D |
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checkShape, checkShape, columns, columnStride, rows, rowStride, size, toStringShort |
Methods inherited from class cern.colt.matrix.AbstractMatrix |
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isView |
Methods inherited from class cern.colt.PersistentObject |
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clone |
Methods inherited from class java.lang.Object |
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getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public SparseFloatMatrix2D(float[][] values)
The values are copied. So subsequent changes in values are not reflected in the matrix, and vice-versa.
values
- The values to be filled into the new matrix.
IllegalArgumentException
- if
for any 1 <= row < values.length: values[row].length != values[row-1].length
.public SparseFloatMatrix2D(int rows, int columns)
rows
- the number of rows the matrix shall have.columns
- the number of columns the matrix shall have.
IllegalArgumentException
- if
rows<0 || columns<0 || (float)columns*rows > Integer.MAX_VALUE
.public SparseFloatMatrix2D(int rows, int columns, int initialCapacity, float minLoadFactor, float maxLoadFactor)
OpenIntFloatHashMap
.
rows
- the number of rows the matrix shall have.columns
- the number of columns 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
rows<0 || columns<0 || (float)columns*rows > Integer.MAX_VALUE
.public SparseFloatMatrix2D(int rows, int columns, int[] rowIndexes, int[] columnIndexes, float[] values)
rows
- columns
- rowIndexes
- columnIndexes
- values
- public SparseFloatMatrix2D(int rows, int columns, int[] rowIndexes, int[] columnIndexes, float value)
rows
- columns
- rowIndexes
- columnIndexes
- value
- public SparseFloatMatrix2D(MatrixVectorReader r) throws IOException
r
- matrix reader
IOException
Method Detail |
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public FloatMatrix2D assign(FloatFunction function)
Example:
matrix = 2 x 2 matrix 0.5 1.5 2.5 3.5 // change each cell to its sine matrix.assign(cern.jet.math.Functions.sin); --> 2 x 2 matrix 0.479426 0.997495 0.598472 -0.350783For further examples, see the package doc.
assign
in class FloatMatrix2D
function
- a function object taking as argument the current cell's value.
FloatFunctions
public FloatMatrix2D assign(float value)
assign
in class FloatMatrix2D
value
- the value to be filled into the cells.
public FloatMatrix2D assign(FloatMatrix2D source)
assign
in class FloatMatrix2D
source
- the source matrix to copy from (may be identical to the
receiver).
IllegalArgumentException
- if
columns() != source.columns() || rows() != source.rows()public FloatMatrix2D assign(FloatMatrix2D y, FloatFloatFunction function)
FloatMatrix2D
Example:
// assign x[row,col] = x[row,col]<sup>y[row,col]</sup> m1 = 2 x 2 matrix 0 1 2 3 m2 = 2 x 2 matrix 0 2 4 6 m1.assign(m2, cern.jet.math.Functions.pow); --> m1 == 2 x 2 matrix 1 1 16 729For further examples, see the package doc.
assign
in class FloatMatrix2D
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,
FloatFunctions
public SparseFloatMatrix2D assign(int[] rowIndexes, int[] columnIndexes, float[] values, FloatFloatFunction function)
public SparseFloatMatrix2D assign(int[] rowIndexes, int[] columnIndexes, float value, FloatFloatFunction function)
public int cardinality()
cardinality
in class FloatMatrix2D
public RCFloatMatrix2D convertToRCFloatMatrix2D()
public CCFloatMatrix2D convertToCCFloatMatrix2D()
public RCMFloatMatrix2D convertToRCMFloatMatrix2D()
public CCMFloatMatrix2D convertToCCMFloatMatrix2D()
public AbstractLongFloatMap elements()
elements
in class FloatMatrix2D
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 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 AbstractMatrix
minCapacity
- the desired minimum number of non-zero cells.public FloatMatrix2D forEachNonZero(IntIntFloatFunction function)
FloatMatrix2D
forEachNonZero
in class FloatMatrix2D
function
- a function object taking as argument the current non-zero
cell's row, column and value.
public float getQuick(int row, int column)
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): 0 <= column < columns() && 0 <= row < rows().
getQuick
in class FloatMatrix2D
row
- the index of the row-coordinate.column
- the index of the column-coordinate.
public long index(int row, int column)
index
in class AbstractMatrix2D
row
- the index of the row-coordinate.column
- the index of the column-coordinate.public FloatMatrix2D like(int rows, int columns)
like
in class FloatMatrix2D
rows
- the number of rows the matrix shall have.columns
- the number of columns the matrix shall have.
public FloatMatrix1D like1D(int size)
like1D
in class FloatMatrix2D
size
- the number of cells the matrix shall have.
public void setQuick(int row, int column, float 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): 0 <= column < columns() && 0 <= row < rows().
setQuick
in class FloatMatrix2D
row
- the index of the row-coordinate.column
- the index of the column-coordinate.value
- the value to be filled into the specified cell.public void trimToSize()
Background:
Cells that
trimToSize
in class AbstractMatrix
public FloatMatrix1D vectorize()
vectorize
in class FloatMatrix2D
public FloatMatrix1D zMult(FloatMatrix1D y, FloatMatrix1D z, float alpha, float beta, boolean transposeA)
FloatMatrix2D
zMult
in class FloatMatrix2D
y
- the source vector.z
- the vector where results are to be stored. Set this parameter
to null to indicate that a new result vector shall be
constructed.
public FloatMatrix2D zMult(FloatMatrix2D B, FloatMatrix2D C, float alpha, float beta, boolean transposeA, boolean transposeB)
FloatMatrix2D
zMult
in class FloatMatrix2D
B
- the second source matrix.C
- the matrix where results are to be stored. Set this parameter
to null to indicate that a new result matrix shall be
constructed.
|
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