Module org.tensorflow.ndarray
Package org.tensorflow.ndarray.impl.sparse

Class ByteSparseNdArray

  • All Implemented Interfaces:
    ByteNdArray, NdArray<Byte>, Shaped, SparseNdArray<Byte,​ByteNdArray>
    public class ByteSparseNdArray
extends AbstractSparseNdArray<Byte,​ByteNdArray>
implements ByteNdArray
    sparse array for the byte data type

    A sparse array as two separate dense arrays: indices, values, and a shape that represents the dense shape.

    NOTE: all Sparse Arrays are readonly for the set(NdArray, long...) and setObject(Byte, long...) methods 

    
 ByteSparseNdArray st = new ByteSparseNdArray(
      StdArrays.of(new long[][] {{0, 0}, {1, 2}}),
      NdArrays.vectorOf((byte)1, (byte)255),
      Shape.of(3, 4));

    represents the dense array: 

    
 [[(byte)1, (byte)0, (byte)0, (byte)0]
  [(byte)0, (byte)0, (byte)1, (byte)0]
  [(byte)0, (byte)0, (byte)0, (byte)0]]

    • Constructor Detail

      • ByteSparseNdArray

        protected ByteSparseNdArray​(LongNdArray indices,
                            ByteNdArray values,
                            byte defaultValue,
                            DimensionalSpace dimensions)
        Creates a ByteSparseNdArray with a default value of zero.
        Parameters:
        indices - A 2-D LongNdArray of shape [N, ndims], that specifies the indices of the elements in the sparse array that contain non-default values (elements are zero-indexed). For example, indices=[[1,3], [2,4]] specifies that the elements with indexes of [1,3] and [2,4] have non-default values.
        values - A 1-D NdArray of Byte type and shape [N], which supplies the values for each element in indices. For example, given indices=[[1,3], [2,4]], the parameter values=[18, 3.6] specifies that element [1,3] of the sparse NdArray has a value of 18, and element [2,4] of the NdArray has a value of 3.6.
        defaultValue - Scalar value to set for indices not specified in AbstractSparseNdArray.getIndices()
        dimensions - the dimensional space for the dense object represented by this sparse array,

    • Method Detail

      • create

        public static ByteSparseNdArray create​(LongNdArray indices,
                                       ByteNdArray values,
                                       DimensionalSpace dimensions)
        Creates a new ByteSparseNdArray
        Parameters:
        indices - A 2-D LongNdArray of shape [N, ndims], that specifies the indices of the elements in the sparse array that contain non-default values (elements are zero-indexed). For example, indices=[[1,3], [2,4]] specifies that the elements with indexes of [1,3] and [2,4] have non-default values.
        values - A 1-D NdArray of any type and shape [N], which supplies the values for each element in indices. For example, given indices=[[1,3], [2,4]], the parameter values=[18, 3.6] specifies that element [1,3] of the sparse NdArray has a value of 18, and element [2,4] of the NdArray has a value of 3.6.
        dimensions - the dimensional space for the dense object represented by this sparse array.
        Returns:
        the new Sparse Array

      • create

        public static ByteSparseNdArray create​(LongNdArray indices,
                                       ByteNdArray values,
                                       byte defaultValue,
                                       DimensionalSpace dimensions)
        Creates a new ByteSparseNdArray
        Parameters:
        indices - A 2-D LongNdArray of shape [N, ndims], that specifies the indices of the elements in the sparse array that contain non-default values (elements are zero-indexed). For example, indices=[[1,3], [2,4]] specifies that the elements with indexes of [1,3] and [2,4] have non-default values.
        values - A 1-D NdArray of any type and shape [N], which supplies the values for each element in indices. For example, given indices=[[1,3], [2,4]], the parameter values=[18, 3.6] specifies that element [1,3] of the sparse NdArray has a value of 18, and element [2,4] of the NdArray has a value of 3.6.
        defaultValue - Scalar value to set for indices not specified in AbstractSparseNdArray.getIndices()
        dimensions - the dimensional space for the dense object represented by this sparse array.
        Returns:
        the new Sparse Array

      • create

        public static ByteSparseNdArray create​(ByteDataBuffer dataBuffer,
                                       DimensionalSpace dimensions)
        Creates a new ByteSparseNdArray from a data buffer
        Parameters:
        dataBuffer - the databuffer containing the dense array
        dimensions - the dimensional space for the sparse array
        Returns:
        the new Sparse Array

      • create

        public static ByteSparseNdArray create​(ByteDataBuffer dataBuffer,
                                       byte defaultValue,
                                       DimensionalSpace dimensions)
        Creates a new ByteSparseNdArray from a data buffer
        Parameters:
        dataBuffer - the databuffer containing the dense array
        defaultValue - Scalar value to set for indices not specified in AbstractSparseNdArray.getIndices()
        dimensions - the dimensional space for the sparse array
        Returns:
        the new Sparse Array

      • create

        public static ByteSparseNdArray create​(DimensionalSpace dimensions)
        Creates a new empty ByteSparseNdArray from a data buffer
        Parameters:
        dimensions - the dimensions array
        Returns:
        the new Sparse Array

      • create

        public static ByteSparseNdArray create​(ByteDataBuffer buffer,
                                       Shape shape)
        Creates a new empty ByteSparseNdArray from a float data buffer
        Parameters:
        buffer - the data buffer
        shape - the shape of the sparse array.
        Returns:
        the new Sparse Array

      • create

        public static ByteSparseNdArray create​(ByteDataBuffer buffer,
                                       byte defaultValue,
                                       Shape shape)
        Creates a new empty ByteSparseNdArray from a float data buffer
        Parameters:
        buffer - the data buffer
        defaultValue - Scalar value to set for indices not specified in AbstractSparseNdArray.getIndices()
        shape - the shape of the sparse array.
        Returns:
        the new Sparse Array

      • create

        public static ByteSparseNdArray create​(ByteNdArray src)
        Creates a new ByteSparseNdArray from a ByteNdArray
        Parameters:
        src - the ByteNdArray
        Returns:
        the new Sparse Array

      • getByte

        public byte getByte​(long... coordinates)
        Returns the byte value of the scalar found at the given coordinates.

        To access the scalar element, the number of coordinates provided must be equal to the number of dimensions of this array (i.e. its rank). For example: 

        
  ByteNdArray matrix = NdArrays.ofBytes(shape(2, 2));  // matrix rank = 2
  matrix.getByte(0, 1);  // succeeds, returns 0
  matrix.getByte(0);  // throws IllegalRankException

  ByteNdArray scalar = matrix.get(0, 1);  // scalar rank = 0
  scalar.getByte();  // succeeds, returns 0
        Specified by:
        getByte in interface ByteNdArray
        Parameters:
        coordinates - coordinates of the scalar to resolve
        Returns:
        value of that scalar

      • setByte

        public ByteNdArray setByte​(byte value,
                           long... coordinates)
        Assigns the byte value of the scalar found at the given coordinates.

        To access the scalar element, the number of coordinates provided must be equal to the number of dimensions of this array (i.e. its rank). For example: 

        
  ByteNdArray matrix = NdArrays.ofBytes(shape(2, 2));  // matrix rank = 2
  matrix.setByte(10, 0, 1);  // succeeds
  matrix.setByte(10, 0);  // throws IllegalRankException

  ByteNdArray scalar = matrix.get(0, 1);  // scalar rank = 0
  scalar.setByte(10);  // succeeds
        Specified by:
        setByte in interface ByteNdArray
        Parameters:
        value - the value to assign
        coordinates - coordinates of the scalar to assign
        Returns:
        this array

      • read

        public ByteNdArray read​(DataBuffer<Byte> dst)
        Read the content of this N-dimensional array into the destination buffer.

        The size of the buffer must be equal or greater to the Shaped.size() of this array, or an exception is thrown. After the copy, content of the buffer and of the array can be altered independently, without affecting each other.

        Specified by:
        read in interface ByteNdArray
        Specified by:
        read in interface NdArray<Byte>
        Parameters:
        dst - the destination buffer
        Returns:
        this array
        See Also:
        DataBuffer.size()

      • write

        public ByteNdArray write​(DataBuffer<Byte> src)
        Write the content of this N-dimensional array from the source buffer.

        The size of the buffer must be equal or greater to the Shaped.size() of this array, or an exception is thrown. After the copy, content of the buffer and of the array can be altered independently, without affecting each other.

        Specified by:
        write in interface ByteNdArray
        Specified by:
        write in interface NdArray<Byte>
        Parameters:
        src - the source buffer
        Returns:
        this array
        See Also:
        DataBuffer.size()

      • fromDense

        public ByteNdArray fromDense​(ByteNdArray src)
        Populates this sparse array from a dense array
        Parameters:
        src - the dense array
        Returns:
        this sparse array

      • slice

        public ByteNdArray slice​(Index... indices)
        Creates a multi-dimensional view (or slice) of this array by mapping one or more dimensions to the given index selectors.

        Slices allow to traverse an N-dimensional array in any of its axis and/or to filter only elements of interest. For example, for a given matrix on the [x, y] axes, it is possible to iterate elements at y=0 for all x.

        Any changes applied to the returned slice affect the data of this array as well, as there is no copy involved.

        Example of usage: 

        
    FloatNdArray matrix3d = NdArrays.ofFloats(shape(3, 2, 4));  // with [x, y, z] axes

    // Iterates elements on the x axis by preserving only the 3rd value on the z axis,
    // (i.e. [x, y, 2])
    matrix3d.slice(all(), all(), at(2)).elements(0).forEach(m -> {
      assertEquals(shape(2), m); // y=2, z=0 (scalar)
    });

    // Creates a slice that contains only the last element of the y axis and elements with an
    // odd `z` coordinate.
    FloatNdArray slice = matrix3d.slice(all(), at(1), odd());
    assertEquals(shape(3, 2), slice.shape());  // x=3, y=0 (scalar), z=2 (odd coordinates)

    // Iterates backward the elements on the x axis
    matrix3d.slice(flip()).elements(0).forEach(m -> {
      assertEquals(shape(2, 4), m);  // y=2, z=4
    });
        Specified by:
        slice in interface ByteNdArray
        Specified by:
        slice in interface NdArray<Byte>
        Overrides:
        slice in class AbstractSparseNdArray<Byte,​ByteNdArray>
        Parameters:
        indices - index selectors per dimensions, starting from dimension 0 of this array.
        Returns:
        the element resulting of the index selection

      • get

        public ByteNdArray get​(long... coordinates)
        Returns the N-dimensional element of this array at the given coordinates.

        Elements of any of the dimensions of this array can be retrieved. For example, if the number of coordinates is equal to the number of dimensions of this array, then a rank-0 (scalar) array is returned, which value can then be obtained by calling `array.getObject()`.

        Any changes applied to the returned elements affect the data of this array as well, as there is no copy involved.

        Note that invoking this method is an equivalent and more efficient way to slice this array on single scalar, i.e. array.get(x, y, z) is equal to array.slice(at(x), at(y), at(z))

        Specified by:
        get in interface ByteNdArray
        Specified by:
        get in interface NdArray<Byte>
        Overrides:
        get in class AbstractSparseNdArray<Byte,​ByteNdArray>
        Parameters:
        coordinates - coordinates of the element to access, none will return this array
        Returns:
        the element at this index

      • setObject

        public ByteNdArray setObject​(Byte value,
                             long... coordinates)
        Assigns the value of the scalar found at the given coordinates.

        To access the scalar element, the number of coordinates provided must be equal to the number of dimensions of this array (i.e. its rank). For example: 

        
  FloatNdArray matrix = NdArrays.ofFloats(shape(2, 2));  // matrix rank = 2
  matrix.setObject(10.0f, 0, 1);  // succeeds
  matrix.setObject(10.0f, 0);  // throws IllegalRankException

  FloatNdArray scalar = matrix.get(0, 1);  // scalar rank = 0
  scalar.setObject(10.0f);  // succeeds
        Note: if this array stores values of a primitive type, prefer the usage of the specialized method in the subclass for that type. For example, floatArray.setFloat(10.0f, 0);
        Specified by:
        setObject in interface ByteNdArray
        Specified by:
        setObject in interface NdArray<Byte>
        Overrides:
        setObject in class AbstractSparseNdArray<Byte,​ByteNdArray>
        Parameters:
        value - the value to assign
        coordinates - coordinates of the scalar to assign
        Returns:
        this array

      • set

        public ByteNdArray set​(NdArray<Byte> src,
                       long... coordinates)
        Assigns the value of the N-dimensional element found at the given coordinates.

        The number of coordinates provided can be anywhere between 0 and rank - 1. For example: 

        
  FloatNdArray matrix = NdArrays.ofFloats(shape(2, 2));  // matrix rank = 2
  matrix.set(vector(10.0f, 20.0f), 0);  // success
  matrix.set(scalar(10.0f), 1, 0); // success
        Specified by:
        set in interface ByteNdArray
        Specified by:
        set in interface NdArray<Byte>
        Overrides:
        set in class AbstractSparseNdArray<Byte,​ByteNdArray>
        Parameters:
        src - an array of the values to assign
        coordinates - coordinates of the element to assign
        Returns:
        this array

      • copyTo

        public ByteNdArray copyTo​(NdArray<Byte> dst)
        Copy the content of this array to the destination array.

        The Shaped.shape() of the destination array must be equal to the shape of this array, or an exception is thrown. After the copy, the content of both arrays can be altered independently, without affecting each other.

        Specified by:
        copyTo in interface ByteNdArray
        Specified by:
        copyTo in interface NdArray<Byte>
        Overrides:
        copyTo in class AbstractSparseNdArray<Byte,​ByteNdArray>
        Parameters:
        dst - array to receive a copy of the content of this array
        Returns:
        this array