[Cython] NumPy 1.7+ warnings

[Stefan Behnel]

Hi,

recent NumPy versions are a bit unhappy about Cython code and generate
deprecation warnings about it:

.../numpy/core/include/numpy/npy_1_7_deprecated_api.h:15:2: warning:
#warning "Using deprecated NumPy API, disable it by " "#defining
NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION"

I don't know how much work it would be to port the C code properly, but it
should be mostly about updating the implementation in Cython's
"numpy/__init__.pxd", which is dated anyway.

Given that NumPy 1.7 appeared not much more than a year ago, dropping
support for older versions sounds a bit aggressive, but there should be a
way to keep supporting them by defining some macros, similar to what we do
for CPython in ModuleSetupCode.c. Any volunteers?

The relevant bits of NumPy's C-API are described here:

http://docs.scipy.org/doc/numpy-dev/reference/c-api.array.html

My guess is that most of the work should be replacing direct access to
ndarray struct fields with C macro calls. That won't easily fix user code,
but it's the first major step on the way.

Stefan

[Frédéric Bastien]

Just to help people working on this, here is what I added in Theano:

# numpy 1.7 deprecated the following macro but the new one didn't
# existed in the past
if bool(numpy_ver < [1, 7]):
cxxflags.append("-D NPY_ARRAY_ENSUREARRAY=NPY_ENSUREARRAY")
cxxflags.append("-D NPY_ARRAY_ENSURECOPY=NPY_ENSURECOPY")
cxxflags.append("-D NPY_ARRAY_ALIGNED=NPY_ALIGNED")
cxxflags.append("-D NPY_ARRAY_WRITEABLE=NPY_WRITEABLE")
cxxflags.append("-D NPY_ARRAY_UPDATE_ALL=NPY_UPDATE_ALL")
cxxflags.append("-D NPY_ARRAY_C_CONTIGUOUS=NPY_C_CONTIGUOUS")
cxxflags.append("-D NPY_ARRAY_F_CONTIGUOUS=NPY_F_CONTIGUOUS")


Some of the newer macro that are not deprecated, have been added only in
early version of NumPy. You could do an ifdef on the numpy bersion and add
those macro to be compatible with older numpy version when using the new
macro.

Fred

Post by Stefan Behnel
Hi,
recent NumPy versions are a bit unhappy about Cython code and generate
#warning "Using deprecated NumPy API, disable it by " "#defining
NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION"
I don't know how much work it would be to port the C code properly, but it
should be mostly about updating the implementation in Cython's
"numpy/__init__.pxd", which is dated anyway.
Given that NumPy 1.7 appeared not much more than a year ago, dropping
support for older versions sounds a bit aggressive, but there should be a
way to keep supporting them by defining some macros, similar to what we do
for CPython in ModuleSetupCode.c. Any volunteers?
http://docs.scipy.org/doc/numpy-dev/reference/c-api.array.html
My guess is that most of the work should be replacing direct access to
ndarray struct fields with C macro calls. That won't easily fix user code,
but it's the first major step on the way.
Stefan
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