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roll#

ivy.roll(x, /, shift, *, axis=None, out=None)[source]#

Roll array elements along a specified axis. Array elements that roll beyond the last position are re-introduced at the first position. Array elements that roll beyond the first position are re-introduced at the last position.

Parameters:

  • x (Union[Array, NativeArray, Container]) – input array.

  • shift (Union[int, Sequence[int]]) – number of places by which the elements are shifted. If shift is a tuple, then axis must be a tuple of the same size, and each of the given axes must be shifted by the corresponding element in shift. If shift is an int and axis a tuple, then the same shift must be used for all specified axes. If a shift is positive, then array elements must be shifted positively (toward larger indices) along the dimension of axis. If a shift is negative, then array elements must be shifted negatively (toward smaller indices) along the dimension of axis.

  • axis (Optional[Union[int, Sequence[int]]], default: None) – axis (or axes) along which elements to shift. If axis is None, the array must be flattened, shifted, and then restored to its original shape. Default: None.

  • out (Optional[Array], default: None) – optional output array, for writing the result to. It must have a shape that the inputs broadcast to.

Return type:

Union[Array, Container]

Returns:

ret – an output array having the same data type as x and whose elements, relative to x, are shifted.

This function conforms to the Array API Standard. This docstring is an extension of the docstring in the standard.

Both the description and the type hints above assumes an array input for simplicity, but this function is nestable, and therefore also accepts ivy.Container instances in place of any of the arguments.

Examples

With ivy.Array input:

>>> x = ivy.array([0., 1., 2.])
>>> y = ivy.roll(x, 1)
>>> print(y)
ivy.array([2., 0., 1.])

>>> x = ivy.array([[0., 1., 2.],
...                [3., 4., 5.]])
>>> y = ivy.zeros((2, 3))
>>> ivy.roll(x, 2, axis=-1, out=y)
>>> print(y)
ivy.array([[1., 2., 0.],
           [4., 5., 3.]])

>>> x = ivy.array([[[0., 0.], [1., 3.], [2., 6.]],
...                [[3., 9.], [4., 12.], [5., 15.]]])
>>> ivy.roll(x, shift=(1, -1), axis=(0, 2), out=x)
>>> print(x)
ivy.array([[[ 9., 3.],
            [12., 4.],
            [15., 5.]],
           [[ 0., 0.],
            [ 3., 1.],
            [ 6., 2.]]])

With one ivy.Container input:

>>> x = ivy.Container(a=ivy.array([0., 1., 2.]),
...                   b=ivy.array([3., 4., 5.]))
>>> y = ivy.roll(x, 1)
>>> print(y)
{
    a: ivy.array([2., 0., 1.]),
    b: ivy.array([5., 3., 4.])
}

With multiple ivy.Container inputs:

>>> x = ivy.Container(a=ivy.array([0., 1., 2.]),
...                   b=ivy.array([3., 4., 5.]))
>>> shift = ivy.Container(a=1, b=-1)
>>> y = ivy.roll(x, shift)
>>> print(y)
{
    a: ivy.array([2., 0., 1.]),
    b: ivy.array([4., 5., 3.])
}
Array.roll(self, /, shift, *, axis=None, out=None)[source]#

ivy.Array instance method variant of ivy.roll. This method simply wraps the function, and so the docstring for ivy.roll also applies to this method with minimal changes.

Parameters:

  • self (Array) – input array.

  • shift (Union[int, Sequence[int]]) – number of places by which the elements are shifted. If shift is a tuple, then axis must be a tuple of the same size, and each of the given axes must be shifted by the corresponding element in shift. If shift is an int and axis a tuple, then the same shift must be used for all specified axes. If a shift is positive, then array elements must be shifted positively (toward larger indices) along the dimension of axis. If a shift is negative, then array elements must be shifted negatively (toward smaller indices) along the dimension of axis.

  • axis (Optional[Union[int, Sequence[int]]], default: None) – axis (or axes) along which elements to shift. If axis is None, the array must be flattened, shifted, and then restored to its original shape. Default None.

  • out (Optional[Array], default: None) – optional output array, for writing the result to. It must have a shape that the inputs broadcast to.

Return type:

Array

Returns:

ret – an output array having the same data type as self and whose elements, relative to self, are shifted.

Examples

>>> x = ivy.array([0., 1., 2.])
>>> y = x.roll(1)
>>> print(y)
ivy.array([2., 0., 1.])

>>> x = ivy.array([[0., 1., 2.],
...                [3., 4., 5.]])
>>> y = x.roll(2, axis=-1)
>>> print(y)
ivy.array([[1., 2., 0.],
            [4., 5., 3.]])
Container.roll(self, /, shift, *, axis=None, key_chains=None, to_apply=True, prune_unapplied=False, map_sequences=False, out=None)[source]#

ivy.Container instance method variant of ivy.roll. This method simply wraps the function, and so the docstring for ivy.roll also applies to this method with minimal changes.

Parameters:

  • self (Container) – input container.

  • shift (Union[int, Sequence[int], Container]) – number of places by which the elements are shifted. If shift is a tuple, then axis must be a tuple of the same size, and each of the given axes must be shifted by the corresponding element in shift. If shift is an int and axis a tuple, then the same shift must be used for all specified axes. If a shift is positive, then array elements must be shifted positively (toward larger indices) along the dimension of axis. If a shift is negative, then array elements must be shifted negatively (toward smaller indices) along the dimension of axis.

  • axis (Optional[Union[int, Sequence[int], Container]], default: None) – axis (or axes) along which elements to shift. If axis is None, the array must be flattened, shifted, and then restored to its original shape. Default None.

  • key_chains (Optional[Union[List[str], Dict[str, str], Container]], default: None) – The key-chains to apply or not apply the method to. Default is None.

  • to_apply (Union[bool, Container], default: True) – If True, the method will be applied to key_chains, otherwise key_chains will be skipped. Default is True.

  • prune_unapplied (Union[bool, Container], default: False) – Whether to prune key_chains for which the function was not applied. Default is False.

  • map_sequences (Union[bool, Container], default: False) – Whether to also map method to sequences (lists, tuples). Default is False.

  • out (Optional[Container], default: None) – optional output container, for writing the result to. It must have a shape that the inputs broadcast to.

Return type:

Container

Returns:

ret – an output container having the same data type as self and whose elements, relative to self, are shifted.

Examples

>>> x = ivy.Container(a=ivy.array([0., 1., 2.]), b=ivy.array([3., 4., 5.]))
>>> y = x.roll(1)
>>> print(y)
{
    a: ivy.array([2., 0., 1.]),
    b: ivy.array([5., 3., 4.])
}
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