def _assert_compatible(cube, other):
"""
Checks to see if cube.data and another array can be broadcast to
the same shape using ``numpy.broadcast_arrays``.
"""
# This code previously returned broadcasted versions of the cube
# data and the other array. As numpy.broadcast_arrays does not work
# with masked arrays (it returns them as ndarrays) operations
# involving masked arrays would be broken.
try:
if not isinstance(other, biggus.Array):
data_view, other_view = BA.broadcast_arrays(cube._my_data,
np.asarray(other))
else:
data_view, other_view = BA.broadcast_arrays(cube._my_data, other)
except ValueError as err:
# re-raise
raise ValueError("The array was not broadcastable to the cube's data "
"shape. The error message from numpy when "
"broadcasting:\n{}\nThe cube's shape was {} and the "
"array's shape was {}".format(err, cube.shape,
other.shape))
if cube.shape != data_view.shape:
raise ValueError("The array operation would increase the "
"dimensionality of the cube. The new cube's data "
"would have had to become: {}".format(
data_view.shape))
def _assert_compatible(cube, other):
"""
Checks to see if cube.data and another array can be broadcast to
the same shape using ``numpy.broadcast_arrays``.
"""
# This code previously returned broadcasted versions of the cube
# data and the other array. As numpy.broadcast_arrays does not work
# with masked arrays (it returns them as ndarrays) operations
# involving masked arrays would be broken.
try:
if not isinstance(other, biggus.Array):
data_view, other_view = BA.broadcast_arrays(
cube._my_data, np.asarray(other))
else:
data_view, other_view = BA.broadcast_arrays(cube._my_data, other)
except ValueError as err:
# re-raise
raise ValueError("The array was not broadcastable to the cube's data "
"shape. The error message from numpy when "
"broadcasting:\n{}\nThe cube's shape was {} and the "
"array's shape was {}".format(err, cube.shape,
other.shape))
if cube.shape != data_view.shape:
raise ValueError("The array operation would increase the "
"dimensionality of the cube. The new cube's data "
"would have had to become: {}".format(
data_view.shape))
def _binary_op_common(operation_function,
operation_name,
cube,
other,
new_unit,
dim=None,
in_place=False):
"""
Function which shares common code between binary operations.
operation_function - function which does the operation
(e.g. numpy.divide)
operation_name - the public name of the operation (e.g. 'divide')
cube - the cube whose data is used as the first argument
to `operation_function`
other - the cube, coord, ndarray or number whose data is
used as the second argument
new_unit - unit for the resulting quantity
dim - dimension along which to apply `other` if it's a
coordinate that is not found in `cube`
in_place - whether or not to apply the operation in place to
`cube` and `cube.data`
"""
_assert_is_cube(cube)
if isinstance(other, iris.coords.Coord):
other = _broadcast_cube_coord_data(cube, other, operation_name, dim)
elif isinstance(other, iris.cube.Cube):
try:
BA.broadcast_arrays(cube._my_data, other._my_data)
except ValueError:
other = iris.util.as_compatible_shape(other, cube)._my_data
else:
other = other._my_data
# don't worry about checking for other data types (such as scalars or
# np.ndarrays) because _assert_compatible validates that they are broadcast
# compatible with cube.data
_assert_compatible(cube, other)
def unary_func(x):
ret = operation_function(x, other)
if ret is NotImplemented:
# explicitly raise the TypeError, so it gets raised even if, for
# example, `iris.analysis.maths.multiply(cube, other)` is called
# directly instead of `cube * other`
raise TypeError('cannot %s %r and %r objects' %
(operation_function.__name__, type(x).__name__,
type(other).__name__))
return ret
return _math_op_common(cube, unary_func, new_unit, in_place)
def test_lh_broadcast(self):
a = np.empty([2])
b = np.empty([1, 2])
a1, b1 = BroadcastArray.broadcast_arrays(a, b)
self.assertIs(b1, b)
self.assertIsInstance(a1, BroadcastArray)
self.assertEqual(a1.shape, (1, 2))
def test_lh_broadcast(self):
a = np.empty([2])
b = np.empty([1, 2])
a1, b1 = BroadcastArray.broadcast_arrays(a, b)
self.assertIs(b1, b)
self.assertIsInstance(a1, BroadcastArray)
self.assertEqual(a1.shape, (1, 2))
def _binary_op_common(operation_function, operation_name, cube, other,
new_unit, dim=None, in_place=False):
"""
Function which shares common code between binary operations.
operation_function - function which does the operation
(e.g. numpy.divide)
operation_name - the public name of the operation (e.g. 'divide')
cube - the cube whose data is used as the first argument
to `operation_function`
other - the cube, coord, ndarray or number whose data is
used as the second argument
new_unit - unit for the resulting quantity
dim - dimension along which to apply `other` if it's a
coordinate that is not found in `cube`
in_place - whether or not to apply the operation in place to
`cube` and `cube.data`
"""
_assert_is_cube(cube)
if isinstance(other, iris.coords.Coord):
other = _broadcast_cube_coord_data(cube, other, operation_name, dim)
elif isinstance(other, iris.cube.Cube):
try:
BA.broadcast_arrays(cube._my_data, other._my_data)
except ValueError:
other = iris.util.as_compatible_shape(other, cube)._my_data
else:
other = other._my_data
# don't worry about checking for other data types (such as scalars or
# np.ndarrays) because _assert_compatible validates that they are broadcast
# compatible with cube.data
_assert_compatible(cube, other)
def unary_func(x):
ret = operation_function(x, other)
if ret is NotImplemented:
# explicitly raise the TypeError, so it gets raised even if, for
# example, `iris.analysis.maths.multiply(cube, other)` is called
# directly instead of `cube * other`
raise TypeError('cannot %s %r and %r objects' %
(operation_function.__name__, type(x).__name__,
type(other).__name__))
return ret
return _math_op_common(cube, unary_func, new_unit, in_place)