Class AbstractDenseNdArray<T, U extends NdArray<T>>

java.lang.Object
org.tensorflow.ndarray.impl.dense.AbstractDenseNdArray<T,U>
All Implemented Interfaces:
NdArray<T>, Shaped
Direct Known Subclasses:
BooleanDenseNdArray, ByteDenseNdArray, DenseNdArray, DoubleDenseNdArray, FloatDenseNdArray, IntDenseNdArray, LongDenseNdArray, ShortDenseNdArray
public abstract class AbstractDenseNdArray<T, U extends NdArray<T>> extends Object

  • Field Details

  • Constructor Details

    • AbstractDenseNdArray

      protected AbstractDenseNdArray(DimensionalSpace dimensions)

  • Method Details

    • elements

      public NdArraySequence<U> elements(int dimensionIdx)
      Description copied from interface: NdArray
      Returns a sequence of all elements at a given dimension.

      Logically, the N-dimensional array can be flatten in a single vector, where the scalars of the (n - 1)th element precedes those of the (n)th element, for a total of Shaped.size() values.

      For example, given a n x m matrix on the [x, y] axes, elements are iterated in the following order:

      x0y0, x0y1, ..., x0ym-1, x1y0, x1y1, ..., xn-1ym-1

      The returned sequence can then be iterated to visit each elements, either by calling Iterable.forEach(Consumer) or NdArraySequence.forEachIndexed(BiConsumer). 

         // Iterate matrix for initializing each of its vectors
   matrixOfFloats.elements(0).forEach(v -> {
     v.set(vector(1.0f, 2.0f, 3.0f));
   });

   // Iterate a vector for reading each of its scalar
   vectorOfFloats.scalars().forEachIdx((coords, s) -> {
     System.out.println("Value " + s.getFloat() + " found at " + coords);
   });
      Parameters:
      dimensionIdx - index of the dimension
      Returns:
      an NdArray sequence

    • withShape

      public U withShape(Shape shape)
      Description copied from interface: NdArray
      Returns a new N-dimensional view of this array with the given shape.

      The provided shape must comply to the following characteristics:

      • new shape is known (i.e. has no unknown dimension)
      • new shape size is equal to the size of the current shape (i.e. same number of elements)
      For example, 
         NdArrays.ofInts(Shape.scalar()).withShape(Shape.of(1, 1));  // ok
   NdArrays.ofInts(Shape.of(2, 3).withShape(Shape.of(3, 2));   // ok
   NdArrays.ofInts(Shape.scalar()).withShape(Shape.of(1, 2));  // not ok, sizes are different (1 != 2)
   NdArrays.ofInts(Shape.of(2, 3)).withShape(Shape.unknown()); // not ok, new shape unknown

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

      Parameters:
      shape - the new shape to apply
      Returns:
      a new array viewing the data according to the new shape, or this array if shapes are the same

    • slice

      public U slice(long position, DimensionalSpace sliceDimensions)

    • slice

      public U slice(Index... indices)
      Description copied from interface: NdArray
      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
   });
      Parameters:
      indices - index selectors per dimensions, starting from dimension 0 of this array.
      Returns:
      the element resulting of the index selection

    • get

      public U get(long... coords)
      Description copied from interface: NdArray
      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))

      Parameters:
      coords - coordinates of the element to access, none will return this array
      Returns:
      the element at this index

    • getObject

      public T getObject(long... coords)
      Description copied from interface: NdArray
      Returns 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.getObject(0, 1);  // succeeds, returns 0.0f
 matrix.getObject(0);  // throws IllegalRankException

 FloatNdArray scalar = matrix.get(0, 1);  // scalar rank = 0
 scalar.getObject();  // succeeds, returns 0.0f
      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.getFloat(0); .
      Parameters:
      coords - coordinates of the scalar to resolve
      Returns:
      value of that scalar

    • set

      public U set(NdArray<T> src, long... coordinates)
      Description copied from interface: NdArray
      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
      Parameters:
      src - an array of the values to assign
      coordinates - coordinates of the element to assign
      Returns:
      this array

    • setObject

      public U setObject(T value, long... coords)
      Description copied from interface: NdArray
      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);
      Parameters:
      value - the value to assign
      coords - coordinates of the scalar to assign
      Returns:
      this array

    • copyTo

      public U copyTo(DataBuffer<T> dst)
      Description copied from interface: NdArray
      Copy 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.

      Note: in version 0.4.0 and earlier, this method was named read(DataBuffer<T>). It has been renamed to explicitly indicate the direction of the data flow to avoid confusion.

      Parameters:
      dst - the destination buffer
      Returns:
      this array
      See Also:

    • copyFrom

      public U copyFrom(DataBuffer<T> src)
      Description copied from interface: NdArray
      Copy the content of the source buffer into this N-dimensional array.

      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.

      Note: in version 0.4.0 and earlier, this method was named write(DataBuffer<T>). It has been renamed to explicitly indicate the direction of the data flow to avoid confusion.

      Parameters:
      src - the source buffer
      Returns:
      this array
      See Also:

    • hashCode

      public int hashCode()

    • equals

      public boolean equals(Object obj)
      Description copied from interface: NdArray
      Checks equality between n-dimensional arrays.

      An array is equal to another object if this object is another NdArray of the same shape, type and the elements are equal and in the same order. For example: 

      IntNdArray array = NdArrays.ofInts(Shape.of(2, 2))
   .set(NdArrays.vectorOf(1, 2), 0)
   .set(NdArrays.vectorOf(3, 4), 1);

assertEquals(array, StdArrays.ndCopyOf(new int[][] {{1, 2}, {3, 4}}));  // true
assertEquals(array, StdArrays.ndCopyOf(new Integer[][] {{1, 2}, {3, 4}}));  // true, as Integers are equal to ints
assertNotEquals(array, NdArrays.vectorOf(1, 2, 3, 4));  // false, different shapes
assertNotEquals(array, StdArrays.ndCopyOf(new int[][] {{3, 4}, {1, 2}}));  // false, different order
assertNotEquals(array, StdArrays.ndCopyOf(new long[][] {{1L, 2L}, {3L, 4L}}));  // false, different types

      Note that the computation required to verify equality between two arrays can be expensive in some cases and therefore, it is recommended to not use this method in a critical path where performances matter.

      Specified by:
      equals in interface NdArray<T>
      Parameters:
      obj - object to compare this array with
      Returns:
      true if this array is equal to the provided object

    • toString

      public String toString()
      A String showing the type and shape of this dense ndarray.
      Overrides:
      toString in class Object
      Returns:
      A string containing the type and shape.

    • buffer

      protected abstract DataBuffer<T> buffer()

    • slowCopyTo

      protected void slowCopyTo(NdArray<T> array)

    • dimensions

      public DimensionalSpace dimensions()

    • shape

      public Shape shape()
      Specified by:
      shape in interface Shaped
      Returns:
      the shape of this container

    • scalars

      public NdArraySequence<U> scalars()
      Description copied from interface: NdArray
      Returns a sequence of all scalars in this array.

      This is equivalent to call elements(shape().numDimensions() - 1)

      Specified by:
      scalars in interface NdArray<T>
      Returns:
      an NdArray sequence

    • slowHashCode

      protected int slowHashCode()

    • slowEquals

      protected boolean slowEquals(NdArray<?> array)