Hi Marc, On Wed, Jul 31, 2013 at 1:09 PM, Marc de Klerk <deklerkmc@gmail.com> wrote:

Hi guys,

I've been using np.ravel(). This morning I tried to lookup the difference between np.ravel() and np.ascontiguousarray(). Does anybody know?

I am not sure if this helps as I don't know your purpose for using np.ravel / np.ascontiguousarray. I got to know about the ndarray.flags method yesterday from Stefan while discussion on this PR<https://github.com/scikit-image/scikit-image/pull/668> . In [15]: a = np.arange(20).reshape((4,5)) In [16]: a Out[16]: array([[ 0, 1, 2, 3, 4], [ 5, 6, 7, 8, 9], [10, 11, 12, 13, 14], [15, 16, 17, 18, 19]]) In [17]: a.flags Out[17]: C_CONTIGUOUS : True F_CONTIGUOUS : False OWNDATA : False WRITEABLE : True ALIGNED : True UPDATEIFCOPY : False In [18]: b = np.ravel(a) In [20]: b Out[20]: array([ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]) In [21]: b.flags Out[21]: C_CONTIGUOUS : True F_CONTIGUOUS : True OWNDATA : False WRITEABLE : True ALIGNED : True UPDATEIFCOPY : False Hope this helps!! Marc

On Sunday, July 21, 2013 6:37:47 AM UTC+2, Chintak Sheth wrote:

...

Hi Ronnie,

On Jul 21, 2013 10:00 AM, "Ronnie Ghose" <ronnie...@gmail.com> wrote:

...

So in skimage/colors why does it matter if the array is contiguous? Is

this for Cython operations later?

...

Yeah it is mainly for using memory views in Cython which is initialized as C contiguous. `cdef some_type[:. ::1] var_name`

In thus case ::1 is for C contiguous.

Chintak

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