diff options
Diffstat (limited to 'numpy/lib/stride_tricks.py')
| -rw-r--r-- | numpy/lib/stride_tricks.py | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/numpy/lib/stride_tricks.py b/numpy/lib/stride_tricks.py index 0dc36e41c..8aafd094b 100644 --- a/numpy/lib/stride_tricks.py +++ b/numpy/lib/stride_tricks.py @@ -121,18 +121,18 @@ def _broadcast_to(array, shape, subok, readonly): if any(size < 0 for size in shape): raise ValueError('all elements of broadcast shape must be non-' 'negative') - needs_writeable = not readonly and array.flags.writeable - extras = ['reduce_ok'] if needs_writeable else [] - op_flag = 'readwrite' if needs_writeable else 'readonly' + extras = [] it = np.nditer( (array,), flags=['multi_index', 'refs_ok', 'zerosize_ok'] + extras, - op_flags=[op_flag], itershape=shape, order='C') + op_flags=['readonly'], itershape=shape, order='C') with it: # never really has writebackifcopy semantics broadcast = it.itviews[0] result = _maybe_view_as_subclass(array, broadcast) - if needs_writeable and not result.flags.writeable: + # In a future version this will go away + if not readonly and array.flags._writeable_no_warn: result.flags.writeable = True + result.flags._warn_on_write = True return result @@ -186,8 +186,6 @@ def _broadcast_shape(*args): """Returns the shape of the arrays that would result from broadcasting the supplied arrays against each other. """ - if not args: - return () # use the old-iterator because np.nditer does not handle size 0 arrays # consistently b = np.broadcast(*args[:32]) @@ -224,8 +222,15 @@ def broadcast_arrays(*args, **kwargs): broadcasted : list of arrays These arrays are views on the original arrays. They are typically not contiguous. Furthermore, more than one element of a - broadcasted array may refer to a single memory location. If you - need to write to the arrays, make copies first. + broadcasted array may refer to a single memory location. If you need + to write to the arrays, make copies first. While you can set the + ``writable`` flag True, writing to a single output value may end up + changing more than one location in the output array. + + .. deprecated:: 1.17 + The output is currently marked so that if written to, a deprecation + warning will be emitted. A future version will set the + ``writable`` flag False so writing to it will raise an error. Examples -------- @@ -262,7 +267,5 @@ def broadcast_arrays(*args, **kwargs): # Common case where nothing needs to be broadcasted. return args - # TODO: consider making the results of broadcast_arrays readonly to match - # broadcast_to. This will require a deprecation cycle. return [_broadcast_to(array, shape, subok=subok, readonly=False) for array in args] |