cern.colt.matrix.tfloat.impl

Class SparseFloatMatrix3D

java.lang.Object

cern.colt.PersistentObject

cern.colt.matrix.AbstractMatrix

cern.colt.matrix.AbstractMatrix3D

cern.colt.matrix.tfloat.FloatMatrix3D

cern.colt.matrix.tfloat.impl.SparseFloatMatrix3D

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable

public class SparseFloatMatrix3D
extends FloatMatrix3D

Sparse hashed 3-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

• 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 100 x 100 x 100 matrix with minLoadFactor=0.25 and maxLoadFactor=0.5 and 1000000 non-zero cells consumes between 25 MB and 50 MB. The same 100 x 100 x 100 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 (in decreasing order of significance): slice major, row major, column major. Applications demanding utmost speed can exploit this fact. Setting/getting values in a loop slice-by-slice, row-by-row, column-by-column is quicker than, for example, column-by-column, row-by-row, slice-by-slice. Thus

 for (int slice = 0; slice < slices; slice++) {
     for (int row = 0; row < rows; row++) {
         for (int column = 0; column < columns; column++) {
             matrix.setQuick(slice, row, column, someValue);
         }
     }
 }
 

is quicker than

 for (int column = 0; column < columns; column++) {
     for (int row = 0; row < rows; row++) {
         for (int slice = 0; slice < slices; slice++) {
             matrix.setQuick(slice, row, column, someValue);
         }
     }
 }
 

See Also:

cern.colt.map, OpenIntFloatHashMap, Serialized Form

Constructor Summary

Constructors

Constructor and Description
SparseFloatMatrix3D(float[][][] values) Constructs a matrix with a copy of the given values.
SparseFloatMatrix3D(int slices, int rows, int columns) Constructs a matrix with a given number of slices, rows and columns and default memory usage.
SparseFloatMatrix3D(int slices, int rows, int columns, int initialCapacity, float minLoadFactor, float maxLoadFactor) Constructs a matrix with a given number of slices, rows and columns using memory as specified.

Method Summary

Modifier and Type	Method and Description
FloatMatrix3D	assign(float value) Sets all cells to the state specified by value.
int	cardinality() Returns the number of cells having non-zero values; ignores tolerance.
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 (non-null) cells without needing to allocate new internal memory.
float	getQuick(int slice, int row, int column) Returns the matrix cell value at coordinate [slice,row,column].
long	index(int slice, int row, int column) Returns the position of the given coordinate within the (virtual or non-virtual) internal 1-dimensional array.
FloatMatrix3D	like(int slices, int rows, int columns) Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified number of slices, rows and columns.
FloatMatrix2D	like2D(int rows, int columns) Construct and returns a new 2-d matrix of the corresponding dynamic type, sharing the same cells.
void	setQuick(int slice, int row, int column, float value) Sets the matrix cell at coordinate [slice,row,column] to the specified value.
java.lang.String	toString() Returns a string representation using default formatting.
void	trimToSize() Releases any superfluous internal memory.
FloatMatrix1D	vectorize() Returns a vector obtained by stacking the columns of each slice of the matrix on top of one another.

Methods inherited from class cern.colt.matrix.tfloat.FloatMatrix3D

aggregate, aggregate, aggregate, aggregate, assign, assign, assign, assign, assign, assign, assign, assign, copy, equals, equals, get, getMaxLocation, getMinLocation, getNegativeValues, getNonZeros, getPositiveValues, like, normalize, set, toArray, viewColumn, viewColumnFlip, viewDice, viewPart, viewRow, viewRowFlip, viewSelection, viewSelection, viewSlice, viewSliceFlip, viewSorted, viewStrides, zAssign27Neighbors, zSum

Methods inherited from class cern.colt.matrix.AbstractMatrix3D

checkShape, checkShape, columns, columnStride, rows, rowStride, size, slices, sliceStride, 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

SparseFloatMatrix3D

public SparseFloatMatrix3D(float[][][] values)

Constructs a matrix with a copy of the given values. values is required to have the form values[slice][row][column] and have exactly the same number of rows in in every slice and exactly the same number of columns in in every row.

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.

Throws:

java.lang.IllegalArgumentException - if for any 1 <= slice < values.length: values[slice].length != values[slice-1].length .

java.lang.IllegalArgumentException - if for any 1 <= row < values[0].length: values[slice][row].length != values[slice][row-1].length .

SparseFloatMatrix3D

public SparseFloatMatrix3D(int slices,
                           int rows,
                           int columns)

Constructs a matrix with a given number of slices, rows and columns and default memory usage. All entries are initially 0.

Parameters:

slices - the number of slices the matrix shall have.

rows - the number of rows the matrix shall have.

columns - the number of columns the matrix shall have.

Throws:

java.lang.IllegalArgumentException - if (float)slices*columns*rows > Integer.MAX_VALUE.

java.lang.IllegalArgumentException - if slices<0 || rows<0 || columns<0.

SparseFloatMatrix3D

public SparseFloatMatrix3D(int slices,
                           int rows,
                           int columns,
                           int initialCapacity,
                           float minLoadFactor,
                           float maxLoadFactor)

Constructs a matrix with a given number of slices, rows and columns using memory as specified. All entries are initially 0. For details related to memory usage see OpenIntFloatHashMap.

Parameters:

slices - the number of slices the matrix shall have.

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.

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 (double)columns*rows > Integer.MAX_VALUE.

java.lang.IllegalArgumentException - if slices<0 || rows<0 || columns<0.

Method Detail

assign

public FloatMatrix3D assign(float value)

Description copied from class: FloatMatrix3D

Sets all cells to the state specified by value.

Overrides:

assign in class FloatMatrix3D

Parameters:

value - the value to be filled into the cells.

Returns:

this (for convenience only).

cardinality

public int cardinality()

Description copied from class: FloatMatrix3D

Returns the number of cells having non-zero values; ignores tolerance.

Overrides:

cardinality in class FloatMatrix3D

Returns:

the number of cells having non-zero values.

elements

public AbstractLongFloatMap elements()

Description copied from class: FloatMatrix3D

Returns the elements of this matrix.

Specified by:

elements in class FloatMatrix3D

Returns:

the elements

ensureCapacity

public void ensureCapacity(int minCapacity)

Description copied from class: AbstractMatrix

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

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

Overrides:

ensureCapacity in class AbstractMatrix

Parameters:

minCapacity - the desired minimum number of non-zero (non-null) cells.

getQuick

public float getQuick(int slice,
                      int row,
                      int column)

Description copied from class: FloatMatrix3D

Returns the matrix cell value at coordinate [slice,row,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): slice<0 || slice>=slices() || row<0 || row>=rows() || column<0 || column>=column().

Specified by:

getQuick in class FloatMatrix3D

Parameters:

slice - the index of the slice-coordinate.

row - the index of the row-coordinate.

column - the index of the column-coordinate.

Returns:

the value at the specified coordinate.

index

public long index(int slice,
                  int row,
                  int column)

Description copied from class: AbstractMatrix3D

Returns the position of the given coordinate within the (virtual or non-virtual) internal 1-dimensional array.

Overrides:

index in class AbstractMatrix3D

Parameters:

slice - the index of the slice-coordinate.

row - the index of the row-coordinate.

column - the index of the third-coordinate.

like

public FloatMatrix3D like(int slices,
                          int rows,
                          int columns)

Description copied from class: FloatMatrix3D

Construct and returns a new empty matrix of the same dynamic type as the receiver, having the specified number of slices, rows and columns. For example, if the receiver is an instance of type DenseFloatMatrix3D the new matrix must also be of type DenseFloatMatrix3D, if the receiver is an instance of type SparseFloatMatrix3D the new matrix must also be of type SparseFloatMatrix3D, etc. In general, the new matrix should have internal parametrization as similar as possible.

Specified by:

like in class FloatMatrix3D

Parameters:

slices - the number of slices the matrix shall have.

rows - the number of rows the matrix shall have.

columns - the number of columns the matrix shall have.

Returns:

a new empty matrix of the same dynamic type.

like2D

public FloatMatrix2D like2D(int rows,
                            int columns)

Description copied from class: FloatMatrix3D

Construct and returns a new 2-d matrix of the corresponding dynamic type, sharing the same cells. For example, if the receiver is an instance of type DenseFloatMatrix3D the new matrix must also be of type DenseFloatMatrix2D, if the receiver is an instance of type SparseFloatMatrix3D the new matrix must also be of type SparseFloatMatrix2D, etc.

Specified by:

like2D in class FloatMatrix3D

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.

setQuick

public void setQuick(int slice,
                     int row,
                     int column,
                     float value)

Description copied from class: FloatMatrix3D

Sets the matrix cell at coordinate [slice,row,column] 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): slice<0 || slice>=slices() || row<0 || row>=rows() || column<0 || column>=column().

Specified by:

setQuick in class FloatMatrix3D

Parameters:

slice - the index of the slice-coordinate.

row - the index of the row-coordinate.

column - the index of the column-coordinate.

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

toString

public java.lang.String toString()

Description copied from class: FloatMatrix3D

Returns a string representation using default formatting.

Overrides:

toString in class FloatMatrix3D

See Also:

FloatFormatter

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

vectorize

public FloatMatrix1D vectorize()

Description copied from class: FloatMatrix3D

Returns a vector obtained by stacking the columns of each slice of the matrix on top of one another.

Specified by:

vectorize in class FloatMatrix3D

Returns:

a vector obtained by stacking the columns of each slice of the matrix on top of one another.