On 13/10/14 01:18, Nathaniel Smith wrote: > On Mon, Oct 13, 2014 at 12:07 AM, Pauli Virtanen <p...@iki.fi> wrote: >> 12.10.2014, 22:16, Eric Firing kirjoitti: >>> On 2014/10/12, 8:29 AM, Pauli Virtanen wrote: >>>> 12.10.2014, 20:19, Mads Ipsen kirjoitti: >>>>> Is there any way for me to detect (on the Python side) that transpose() >>>>> has been invoked on the matrix, and thereby only do the copy operation >>>>> when it really is needed? >>>> >>>> The correct way to do this is to, either: >>>> >>>> In your C code check PyArray_IS_C_CONTIGUOUS(obj) and raise an error if >>>> it is not. In addition, on the Python side, check for >>>> `a.flags.c_contiguous` and make a copy if it is not. >>>> >>>> OR >>>> >>>> In your C code, get an handle to the array using PyArray_FromANY (or >>>> PyArray_FromOTF) with NPY_ARRAY_C_CONTIGUOUS requirement set so that it >>>> makes a copy when necessary. >>> >>> or let numpy handle it on the python side: >>> >>> foo(numpy.ascontiguousarray(a)) >> >> Yes, but the C code really should check that the input array is >> C-contiguous, if it only works for C-contiguous inputs. > > I.e. your original instructions were correct, but instead of checking > a.flags.c_contiguous by hand etc. the OP should just call > ascontiguousarray which takes care of that part. > Hi,
To everybody that answered - your help is (as always) much appreciated. Best regards, Mads -- +---------------------------------------------------------+ | Mads Ipsen | +----------------------+----------------------------------+ | Gåsebæksvej 7, 4. tv | phone: +45-29716388 | | DK-2500 Valby | email: mads.ip...@gmail.com | | Denmark | map : www.tinyurl.com/ns52fpa | +----------------------+----------------------------------+ _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion
