SparseFloatMatrix3D
cern.colt.matrix.tfloat.impl

Class SparseFloatMatrix3D

  • All Implemented Interfaces:
    Serializable, Cloneable


    public class SparseFloatMatrix3Dextends 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 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:
        IllegalArgumentException - if for any 1 <= slice < values.length: values[slice].length != values[slice-1].length .
        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:
        IllegalArgumentException - if (float)slices*columns*rows > Integer.MAX_VALUE.
        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:
        IllegalArgumentException - if initialCapacity < 0 || (minLoadFactor < 0.0 || minLoadFactor >= 1.0) || (maxLoadFactor <= 0.0 || maxLoadFactor >= 1.0) || (minLoadFactor >= maxLoadFactor) .
        IllegalArgumentException - if (double)columns*rows > Integer.MAX_VALUE.
        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.
      • 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.
      • 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.

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