13.1. Group creation routines

dana.zeros

dana.ones

dana.empty

dana.zeros_like

dana.ones_like

dana.empty_like

zeros(shape, dtype=<type 'float'>)

Return a new group of given shape and type, filled with zeros.

Parameters:

• shape (tuple) – Shape of the new group, e.g., (2, 3) or 2.
• dtype – The desired data-type for the group, e.g., . Default is .

Returns:

Group with the given shape and dtype filled with zeros.

Examples

>>> dana.zeros((2,2))
Group([[0.0, 0.0],
       [0.0, 0.0]],
      dtype=[('f0', '<f8')])
>>> dana.zeros((2,2), dtype=int)
Group([[0, 0],
       [0, 0]],
      dtype=[('f0', '<f8')])

See also

• dana.ones() : Return a new group setting values to one.
• dana.empty() : Return a new uninitialized group.
• dana.zeros_like() : Return an group of zeros with shape and type of input.
• dana.ones_like() : Return an group of ones with shape and type of input.
• dana.empty_like() : Return an empty group with shape and type of input.

ones(shape, dtype=<type 'float'>)

Return a new group of given shape and type, filled with ones.

Parameters:

• shape (tuple) – Shape of the new group, e.g., (2, 3) or 2.
• dtype – The desired data-type for the group, e.g., . Default is .

Returns:

Group with the given shape and dtype filled with zeros.

Examples

>>> dana.ones((2,2))
Group([[1.0, 1.0],
       [1.0, 1.0]],
      dtype=[('f0', '<f8')])
>>> dana.ones((2,2), dtype=int)
Group([[1, 1],
       [1, 1]],
      dtype=[('f0', '<f8')])

See also

• dana.zeros() : Return a new group setting values to zero.
• dana.empty() : Return a new uninitialized group.
• dana.zeros_like() : Return an group of zeros with shape and type of input.
• dana.ones_like() : Return an group of ones with shape and type of input.
• dana.empty_like() : Return an empty group with shape and type of input.

empty(shape, dtype=<type 'float'>)

Return a new group of given shape and type, without initialising entries.

Parameters:

• shape (tuple) – Shape of the new group, e.g., (2, 3) or 2.
• dtype – The desired data-type for the group, e.g., . Default is .

Returns:

Group with the given shape and dtype filled with zeros.

Notes

, unlike , does not set the group values to zero, and may therefore be marginally faster. On the other hand, it requires the user to manually set all the values in the group, and should be used with caution.

Examples

>>> Group.empty((2,2))
Group([[6.94248367807e-310, 1.34841898023e-316],
       [1.34841977073e-316, 0.0]],
      dtype=[('f0', '<f8')])

See also

• dana.zeros() : Return a new group setting values to zero.
• dana.ones() : Return a new group setting values to one.
• dana.zeros_like() : Return a group of zeros with shape and type of input.
• dana.ones_like() : Return a group of ones with shape and type of input.
• dana.empty_like() : Return a empty group with shape and type of input.

zeros_like(other)

Create a new group of zeros with the same shape and type as another.

Parameters:other (array) – The shape and data-type of defines the parameters of the returned group. Returns:Group of zeros with same shape and type as .

Examples

>>> x = np.arange(6)
>>> x = x.reshape((2, 3))
>>> x
array([[0, 1, 2],
       [3, 4, 5]])
>>> np.zeros_like(x)
array([[0, 0, 0],
       [0, 0, 0]])

See also

• dana.zeros() : Return a new group setting values to zero.
• dana.ones() : Return a new group setting values to one.
• dana.empty() : Return a new uninitialized group.
• dana.empty_like() : Return an uninitialized group shape and type of input.
• dana.ones_like() : Return a group of ones with shape and type of input.

ones_like(other)

Returns a group of ones with the same shape and type as a given array.

Parameters:other (array) – The shape and data-type of defines the parameters of the returned group. Returns:Group of ones with same shape and type as .

Examples

>>> x = np.arange(6)
>>> x = x.reshape((2, 3))
>>> x
array([[0, 1, 2],
       [3, 4, 5]])
>>> zeros_like(x)
group([[0, 0, 0],
       [0, 0, 0]])

See also

• dana.zeros() : Return a new group setting values to zero.
• dana.ones() : Return a new group setting values to one.
• dana.empty() : Return a new uninitialized group.
• dana.empty_like() : Return an empty group with shape and type of input.
• dana.zeros_like() : Return a group of zeros with shape and type of input.

empty_like(other)

Create a new group with the same shape and type as another.

Parameters:other (array) – The shape and data-type of defines the parameters of the returned group. Returns:Uninitialized group with same shape and type as .

Examples

>>> x = np.arange(6)
>>> x = x.reshape((2, 3))
>>> x
array([[0, 1, 2],
       [3, 4, 5]])
>>> np.zeros_like(x)
array([[0, 0, 0],
       [0, 0, 0]])

See also

• dana.zeros() : Return a new group setting values to zero.
• dana.ones() : Return a new group setting values to one.
• dana.empty() : Return a new uninitialized group.
• dana.ones_like() : Return a group of ones with shape and type of input.
• dana.zeros_like() : Return a group of zeros with shape and type of input.