On Fri, Jul 29, 2011 at 10:07 AM, Mark Wiebe <mwwi...@gmail.com> wrote:
> On Thu, Jul 28, 2011 at 9:58 AM, Hans Meine < > me...@informatik.uni-hamburg.de> wrote: > >> Hi again! >> >> Am Donnerstag, 21. Juli 2011, 16:56:21 schrieb Hans Meine: >> > import numpy >> > >> > class Test(numpy.ndarray): >> > pass >> > >> > a1 = numpy.ndarray((1,)) >> > a2 = Test((1,)) >> > >> > assert type(a1.min()) == type(a2.min()), \ >> > "%s != %s" % (type(a1.min()), type(a2.min())) >> > # --------------------------------------------------- >> > >> > This code fails with 1.6.0, while it worked in 1.3.0. >> >> I just tried with 1.5.1 (Ubuntu natty), and it works, too. >> >> Thus, this behavor-incompatible change happened between 1.5.1 and 1.6.0. >> > > I dug a little bit into the relevant 1.5.x vs 1.6.x code, in the places I > would most suspect a change, but couldn't find anything obvious. Here's the > ndarray.min method: > > > https://github.com/numpy/numpy/blob/maintenance%2F1.5.x/numpy/core/src/multiarray/methods.c#L267 > > https://github.com/numpy/numpy/blob/maintenance%2F1.6.x/numpy/core/src/multiarray/methods.c#L257 > > it calls PyArray_Min, which is here: > > > https://github.com/numpy/numpy/blob/maintenance%2F1.5.x/numpy/core/src/multiarray/calculation.c#L208 > > https://github.com/numpy/numpy/blob/maintenance%2F1.6.x/numpy/core/src/multiarray/calculation.c#L208 > > this calls numpy.minimum.reduce, which ends up here: > > > https://github.com/numpy/numpy/blob/maintenance%2F1.5.x/numpy/core/src/umath/ufunc_object.c#L3194 > > https://github.com/numpy/numpy/blob/maintenance%2F1.6.x/numpy/core/src/umath/ufunc_object.c#L3851 > > This function calls PyArray_Return(ret), which is how things get converted > into the NumPy scalars: > > > https://github.com/numpy/numpy/blob/maintenance%2F1.5.x/numpy/core/src/umath/ufunc_object.c#L3365 > > https://github.com/numpy/numpy/blob/maintenance%2F1.6.x/numpy/core/src/umath/ufunc_object.c#L4019 > > Here's the code for PyArray_Return, which was unchanged: > > > https://github.com/numpy/numpy/blob/maintenance%2F1.5.x/numpy/core/src/multiarray/scalarapi.c#L729 > > https://github.com/numpy/numpy/blob/maintenance%2F1.6.x/numpy/core/src/multiarray/scalarapi.c#L793 > > Something more subtle is going on. I don't have the time to dig into this > more at the moment, but hopefully these pointers into the code can help > anyone out there who has the time to investigate further. We definitely need > to add some tests for the desired behavior here. > > Cheers, > -Mark > > Could it possibly have anything to do with the bug Chuck found in a different thread: No, it comes from this > > In [2]: a = numpy.ma.masked_array([1,2,3, > 4]) > > In [3]: array(a.flat) > Out[3]: array(<numpy.ma.core.MaskedIterator object at 0x1fd1f90>, > dtype='object') > > i.e., the a.flat iterator is turned into an object array with one element. > I'm not sure what the correct fix for this would be. Please open a ticket. > Don't know if they are related, just throwing it out there. Ben Root
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