def eye(N, M=None, k=0, dtype=float, order='C'):
"""Returns a 2-D array with ones on the diagonal and zeros elsewhere.
Parameters
----------
N : int
Number of rows in the output.
M : int, optional
Number of columns in the output. If None, defaults to *N*.
k : int, optional
Index of the diagonal: 0 (the default) refers to the main diagonal, a positive
value refers to an upper diagonal, and a negative value to a lower diagonal.
dtype : dtype, optional
Data-type of the returned array.
order : {'C', 'F'}, optional
Whether the output should be stored in row-major (C-style) or column-major
(Fortran-style) order in memory.
Returns
-------
I : ndarray
An array where all elements are equal to zero, except for the k-th diagonal,
whose values are equal to one.
See Also
--------
identity : Returns the identity array.
diag : Extracts a diagonal or construct a diagonal array.
Examples
--------
>>> import nlcpy as vp
>>> vp.eye(2, dtype=int)
array([[1, 0],
[0, 1]])
>>> vp.eye(3, k=1)
array([[0., 1., 0.],
[0., 0., 1.],
[0., 0., 0.]])
"""
if numpy.dtype(dtype).kind == 'V':
raise NotImplementedError('void dtype in eye is not implemented yet.')
if M is None:
M = N
out = nlcpy.ndarray(shape=(N, M), dtype=dtype, order=order)
if order == 'F':
N, M = M, N
request._push_request(
"nlcpy_eye",
"creation_op",
(out, int(N), int(M), int(k)),
)
return out
def zeros(shape, dtype=float, order='C'):
"""Returns a new array of given shape and type, filled with zeros.
Parameters
----------
shape : int or sequence of ints
Shape of the new array, e.g., ``(2, 3)`` or ``2``.
dtype : dtype, optional
The desired dtype for the array, e.g, ``nlcpy.int64``.
Default is ``nlcpy.float64``.
order : {'C', 'F'}, optional
Whether to store multi-dimensional data in row-major (C-style) or column-major
(Fortran-style) order in memory.
Returns
-------
out : ndarray
Array of zeros with the given shape, dtype, and order.
See Also
--------
zeros_like : Returns an array of zeros with the same shape
and type as a given array.
empty : Returns a new array of given shape and type,
without initializing entries.
ones : Returns a new array of given shape and type,
filled with ones.
full : Returns a new array of given shape and type,
filled with fill_value.
Examples
--------
>>> import nlcpy as vp
>>> vp.zeros(5)
array([0., 0., 0., 0., 0.])
>>> vp.zeros((5,), dtype=int)
array([0, 0, 0, 0, 0])
>>> vp.zeros((2, 1))
array([[0.],
[0.]])
>>> s = (2,2)
>>> vp.zeros(s)
array([[0., 0.],
[0., 0.]])
"""
if numpy.dtype(dtype).kind == 'V':
raise NotImplementedError(
'void dtype in zeros is not implemented yet.')
out = nlcpy.ndarray(shape=shape, dtype=dtype, order=order)
out.fill(0)
return out
def empty(shape, dtype=float, order='C'):
"""Returns a new array of given shape and type, without initializing entries.
Parameters
----------
shape : int or sequence of int
Shape of the empty array, e.g., (2, 3) or 2.
dtype : dtype, optional
Desired output dtype for the array, e.g, ``nlcpy.int64``.
Default is ``nlcpy.float64``.
order : {'C', 'F'}, optional
Whether to store multi-dimensional data in row-major (C-style) or column-major
(Fortran-style) order in memory.
Returns
-------
out : ndarray
Array of uninitialized (arbitrary) data of the given shape, dtype, and order.
Note
----
:func:`empty`, unlike :func:`zeros`, does not set the array 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 array, and should be used with caution.
See Also
--------
empty_like : Returns a new array with the same shape and type
as a given array.
ones : Returns a new array of given shape and type, filled with ones.
zeros : Returns a new array of given shape and type, filled with zeros.
full : Returns a new array of given shape and type,
filled with fill_value.
Examples
--------
>>> import nlcpy as vp
>>> vp.empty([2, 2]) # doctest: +SKIP
array([[0., 0.],
[0., 0.]]) # They are not always zero. (uninitialized)
>>> vp.empty([2, 2], dtype=int) # doctest: +SKIP
array([[0, 0],
[0, 0]]) # They are not always zero. (uninitialized)
"""
return nlcpy.ndarray(shape=shape, dtype=dtype, order=order)
def empty_like(prototype, dtype=None, order='K', subok=False, shape=None):
"""Returns a new array with the same shape and type as a given array.
Parameters
----------
prototype : array_like
The shape and dtype of *prototype* define these same attributes of the returned
array.
dtype : dtype, optional
Overrides the data type of the result.
order : {'C', 'F'}, optional
Overrides the memory layout of the result. 'C' means C-order, 'F' means F-order,
'A' means 'F' if *prototype* is Fortran contiguous, 'C' otherwise. 'K' means
match the layout of *prototype* as closely as possible.
subok : bool, optional
Not implemented.
shape : int or sequence of ints, optional
Overrides the shape of the result. If order='K' and the number of dimensions is
unchanged, will try to keep order, otherwise, order='C' is implied.
Returns
-------
out : ndarray
Array of uninitialized (arbitrary) data with the same shape and type as
*prototype*.
Note
----
This function does not initialize the returned array; to do that use
:func:`zeros_like` or :func:`ones_like` instead. It may be marginally faster than the
functions that do set the array values.
See Also
--------
ones_like : Returns an array of ones with the same shape and type
as a given array.
zeros_like : Returns an array of zeros with the same shape
and type as a given array.
full_like : Returns a full array with the same shape
and type as a given array.
empty : Returns a new array of given shape and type,
without initializing entries.
Examples
--------
>>> import nlcpy as vp
>>> a = ([1,2,3], [4,5,6]) # a is array-like
>>> vp.empty_like(a) # doctest: +SKIP
array([[0, 0, 0],
[0, 0, 0]]) # uninitialized
>>> a = vp.array([[1., 2., 3.],[4.,5.,6.]])
>>> vp.empty_like(a) # doctest: +SKIP
array([[0., 0., 0.],
[0., 0., 0.]]) # uninitialized
"""
if subok is not False:
raise NotImplementedError(
'subok in empty_like is not implemented yet.')
prototype = nlcpy.asanyarray(prototype)
if shape is None:
shape = prototype.shape
if dtype is None:
dtype = prototype.dtype
if order is None or order in 'kKaA':
if prototype._f_contiguous and not prototype._c_contiguous:
order = 'F'
else:
order = 'C'
if numpy.dtype(dtype).kind == 'V':
raise NotImplementedError(
'void dtype in empty_like is not implemented yet.')
out = nlcpy.ndarray(shape=shape, dtype=dtype, order=order)
return out
def full_like(a, fill_value, dtype=None, order='K', subok=False, shape=None):
"""Returns a full array with the same shape and type as a given array.
Parameters
----------
a : array_like
The shape and dtype of *a* define these same attributes of the returned array.
fill_value : scalar
Fill value.
dtype : dtype, optional
Overrides the data type of the result.
order : {'C', 'F', 'A', or 'K'}, optional
Overrides the memory layout of the result. 'C' means C-order, 'F' means F-order,
'A' means 'F' if *a* is Fortran contiguous, 'C' otherwise. 'K' means match the
layout of *a* as closely as possible.
subok : bool, optional
Not implemented.
shape : int or sequence of ints, optional
Overrides the shape of the result. If order='K' and the number of dimensions is
unchanged, will try to keep order, otherwise, order='C' is implied.
Returns
-------
out : ndarray
Array of *fill_value* with the same shape and type as *a*.
See Also
--------
empty_like : Returns a new array with the same shape
and type as a given array.
ones_like : Returns an array of ones with the same shape
and type as a given array.
zeros_like : Returns an array of zeros with the same shape
and type as a given array.
full : Returns a new array of given shape and type,
filled with fill_value.
Examples
--------
>>> import nlcpy as vp
>>> x = vp.arange(6, dtype=int)
>>> vp.full_like(x, 1)
array([1, 1, 1, 1, 1, 1])
>>> vp.full_like(x, 0.1)
array([0, 0, 0, 0, 0, 0])
>>> vp.full_like(x, 0.1, dtype=vp.double)
array([0.1, 0.1, 0.1, 0.1, 0.1, 0.1])
>>> vp.full_like(x, vp.nan, dtype=vp.double)
array([nan, nan, nan, nan, nan, nan])
>>> y = vp.arange(6, dtype=vp.double)
>>> vp.full_like(y, 0.1)
array([0.1, 0.1, 0.1, 0.1, 0.1, 0.1])
"""
if subok is not False:
raise NotImplementedError('subok in full_like is not implemented yet.')
a = nlcpy.asanyarray(a)
if shape is None:
shape = a.shape
if dtype is None:
dtype = a.dtype
else:
dtype = nlcpy.dtype(dtype)
if numpy.dtype(dtype).kind == 'V':
raise NotImplementedError(
'void dtype in full_like is not implemented yet.')
if order is None or order in 'kKaA':
if a._f_contiguous and not a._c_contiguous:
order = 'F'
else:
order = 'C'
if numpy.isscalar(fill_value):
if numpy.iscomplex(fill_value):
if dtype in ('complex64', 'complex128'):
pass
else:
fill_value = numpy.real(fill_value)
warnings.warn(
'Casting complex values to real discards the imaginary part',
numpy.ComplexWarning,
stacklevel=2)
out = nlcpy.ndarray(shape=shape, dtype=dtype, order=order)
out.fill(fill_value)
elif fill_value is None:
raise NotImplementedError('fill_value in nlcpy.full_like is None')
else:
fill_value = nlcpy.asarray(fill_value)
out = nlcpy.array(nlcpy.broadcast_to(fill_value, shape=shape),
dtype=dtype,
order=order)
return out
def full(shape, fill_value, dtype=None, order='C'):
"""Returns a new array of given shape and type, filled with *fill_value*.
Parameters
----------
shape : int or sequence of ints
Shape of the new array, e.g., ``(2, 3)`` or ``2``.
fill_value : scalar
Fill value.
dtype : dtype, optional
The desired dtype for the array, e.g, ``nlcpy.int64``.
Default is ``nlcpy.float64``.
order : {'C', 'F'}, optional
Whether to store multidimensional data in C- or Fortran-contiguous (row- or
column-wise) order in memory.
Returns
-------
out : ndarray
Array of *fill_value* with the given shape, dtype, and order.
See Also
--------
full_like : Returns a full array with the same shape
and type as a given array.
empty : Returns a new array of given shape and type,
without initializing entries.
ones : Returns a new array of given shape and type,
filled with ones.
zeros : Returns a new array of given shape and type,
filled with zeros.
Examples
--------
>>> import nlcpy as vp
>>> vp.full((2, 2), vp.inf)
array([[inf, inf],
[inf, inf]])
>>> vp.full((2, 2), 10)
array([[10, 10],
[10, 10]])
"""
if numpy.dtype(dtype).kind == 'V':
raise NotImplementedError('void dtype in full is not implemented yet.')
if dtype is None:
dtype = numpy.result_type(fill_value)
else:
dtype = nlcpy.dtype(dtype)
if numpy.isscalar(fill_value):
if numpy.iscomplex(fill_value):
if dtype in ('complex64', 'complex128'):
pass
else:
fill_value = numpy.real(fill_value)
warnings.warn(
'Casting complex values to real discards the imaginary part',
numpy.ComplexWarning,
stacklevel=2)
out = nlcpy.ndarray(shape=shape, dtype=dtype, order=order)
out.fill(fill_value)
elif fill_value is None:
raise NotImplementedError('fill_value in nlcpy.full is None')
else:
fill_value = nlcpy.asarray(fill_value)
out = nlcpy.array(nlcpy.broadcast_to(fill_value, shape=shape),
dtype=dtype,
order=order)
return out
def zeros_like(a, dtype=None, order='K', subok=False, shape=None):
"""Returns an array of zeros with the same shape and type as a given array.
Parameters
----------
a : array_like
The shape and dtype of *a* define these same attributes of the returned array.
dtype : dtype, optional
Overrides the data type of the result.
order : {'C', 'F', 'A', or 'K'}, optional
Overrides the memory layout of the result. 'C' means C-order, 'F' means F-order,
'A' means 'F' if *a* is Fortran contiguous, 'C' otherwise. 'K' means match the
layout of *a* as closely as possible.
subok : bool, optional
Not implemented.
shape : int or sequence of ints, optional
Overrides the shape of the result. If order='K' and the number of dimensions is
unchanged, will try to keep order, otherwise, order='C' is implied.
Returns
-------
out : ndarray
Array of zeros with the same shape and type as *a*.
See Also
--------
empty_like : Returns a new array with the same shape and type
as a given array.
ones_like : Returns an array of ones with the same shape
and type as a given array.
full_like : Returns a full array with the same shape
and type as a given array.
zeros : Returns a new array of given shape and type,
filled with zeros.
Examples
--------
>>> import nlcpy as vp
>>> x = vp.arange(6)
>>> x = x.reshape((2, 3))
>>> x
array([[0, 1, 2],
[3, 4, 5]])
>>> vp.zeros_like(x)
array([[0, 0, 0],
[0, 0, 0]])
>>> y = vp.arange(3, dtype=float)
>>> y
array([0., 1., 2.])
>>> vp.zeros_like(y)
array([0., 0., 0.])
"""
if subok is not False:
raise NotImplementedError(
'subok in zeros_like is not implemented yet.')
a = nlcpy.asanyarray(a)
if shape is None:
shape = a.shape
if dtype is None:
dtype = a.dtype
if numpy.dtype(dtype).kind == 'V':
raise NotImplementedError(
'void dtype in zeros_like is not implemented yet.')
if order is None or order in 'kKaA':
if a._f_contiguous and not a._c_contiguous:
order = 'F'
else:
order = 'C'
out = nlcpy.ndarray(shape=shape, dtype=dtype, order=order)
out.fill(0)
return out
def where(condition, x=None, y=None):
"""Returns elements chosen from *x* or *y* depending on *condition*.
Note
----
When only condition is provided, this function is a shorthand for
``nlcpy.asarray(condition).nonzero()``. Using nonzero directly should be preferred,
as it behaves correctly for subclasses. The rest of this documentation covers only
the case where all three arguments are provided.
Parameters
----------
condition : array_like, bool
Where True, yield *x*, otherwise yield *y*.
x, y : array_like
Values from which to choose. *x*, *y* and *condition* need to be broadcastable to
some shape.
Returns
-------
out : ndarray
An array with elements from *x* where *condition* is True, and elements from *y*
elsewhere.
Note
----
If all the arrays are 1-D, :func:`where` is equivalent to::
[xv if c else yv for c, xv, yv in zip(condition, x, y)]
See Also
--------
nonzero : Returns the indices of the elements
that are non-zero.
Examples
--------
>>> import nlcpy as vp
>>> a = vp.arange(10)
>>> a
array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
>>> vp.where(a < 5, a, 10*a)
array([ 0, 1, 2, 3, 4, 50, 60, 70, 80, 90])
This can be used on multidimensional arrays too:
>>> vp.where([[True, False], [True, True]],
... [[1, 2], [3, 4]],
... [[9, 8], [7, 6]])
array([[1, 8],
[3, 4]])
The shapes of x, y, and the condition are broadcast together:
>>> x = vp.arange(3).reshape([3,1])
>>> y = vp.arange(4).reshape([1,4])
>>> vp.where(x < y, x, 10 + y) # both x and 10+y are broadcast
array([[10, 0, 0, 0],
[10, 11, 1, 1],
[10, 11, 12, 2]])
>>> a = vp.array([[0, 1, 2],
... [0, 2, 4],
... [0, 3, 6]])
>>> vp.where(a < 4, a, -1) # -1 is broadcast
array([[ 0, 1, 2],
[ 0, 2, -1],
[ 0, 3, -1]])
"""
if condition is None:
condition = False
arr = nlcpy.asarray(condition)
if x is None and y is None:
return nlcpy.nonzero(arr)
if x is None or y is None:
raise ValueError("either both or neither of x and y should be given")
if not isinstance(x, nlcpy.ndarray):
x = numpy.asarray(x)
if not isinstance(y, nlcpy.ndarray):
y = numpy.asarray(y)
ret_type = numpy.result_type(x, y)
arr_x = nlcpy.asarray(x, dtype=ret_type)
arr_y = nlcpy.asarray(y, dtype=ret_type)
if arr.dtype != bool:
arr = (arr != 0)
values, shape = core._broadcast_core((arr, arr_x, arr_y))
ret = nlcpy.ndarray(shape=shape, dtype=ret_type)
request._push_request(
"nlcpy_where",
"indexing_op",
(ret, values[0], values[1], values[2]),
)
return ret
def test_ones_like_subok(self):
a = nlcpy.ndarray((2, 3, 4))
return nlcpy.ones_like(a, subok=True)