[Numpy-discussion] Change of behavior in flatten between 1.0.4 and 1.1

[Stuart Brorson]

Hi --

I have noticed a change in the behavior of numpy.flatten(True) between
NumPy 1.0.4 and NumPy 1.1.   The change affects 3D arrays.  I am
wondering if this is a bug or a feature.

Here's the change.  Note that the output from flatten(True) is
different between 1.0.4 and 1.1.

=======  First the preliminary set up:  =======

In [3]: A = numpy.array([[[1, 2], [3, 4]], [[5, 6], [7, 8]], [[9, 10],
[11, 12]]])

In [4]: A

Out[4]:

array([[[ 1,  2],
         [ 3,  4]],

        [[ 5,  6],
         [ 7,  8]],

        [[ 9, 10],
         [11, 12]]])

=======  Now the change:  Numpy 1.0.4  =======

In [5]: A.flatten()

Out[5]: array([ 1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12])

In [6]: A.flatten(True)

Out[6]: array([ 1,  5,  9,  2,  6, 10,  3,  7, 11,  4,  8, 12])

=======  Numpy 1.1  =======

In [4]: A.flatten()

Out[4]: array([ 1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12])

In [5]: A.flatten(True)

Out[5]: array([ 1,  5,  9,  3,  7, 11,  2,  6, 10,  4,  8, 12])


Note that the output of A.flatten(True) is different.

Is this a bug or a feature?

Cheers,

Stuart Brorson
Interactive Supercomputing, inc.
135 Beaver Street | Waltham | MA | 02452 | USA
http://www.interactivesupercomputing.com/