On 03/27/2013 10:36 PM, Robert Bradshaw wrote:
On Wed, Mar 27, 2013 at 2:44 AM, Martin Fiers
<martin.fi...@intec.ugent.be> wrote:
On 3/27/2013 3:54 AM, Robert Bradshaw wrote:
On Tue, Mar 26, 2013 at 5:12 PM, Martin Fiers
<martin.fi...@intec.ugent.be> wrote:
On 3/26/2013 6:48 PM, Robert Bradshaw wrote:
On Tue, Mar 26, 2013 at 2:52 AM, Martin Fiers
<martin.fi...@intec.ugent.be> wrote:
Dear Cython developers,
I stumbled upon a strange error when using Cython. I made a minimal
working
example, see attachment for the two necessary files. (btw I didn't find
the
e-mail address of Robert Bradshaw so I could not request him for an
account
on the issue tracker. Is it possible to put the bug on there?)
Sure. You should have my email now.
Thank you! I just sent a mail.
Also, thanks for replying so quickly. Replies follow inline.
To reproduce the bug:
1) Reboot to Windows :) (the bug only appears on Windows)
2) Run compile_bug.py to generate the Cython extension
3) Try to run the my_func_exposed function:
python
import complex_double
(does not crash)
complex_double.my_func_exposed(1,1j)
(crashes)
complex_double.my_func_exposed(1,1)
If I put a breakpoint in the code with gdb, jump in the code, and leave
the
function again, it does not crash! Also, it is no problem on Linux.
It has to do with the fact that in the first case, a real value was
used.
In
the complex-value case, it does not crash. I went through the generated
cpp
file and I don't see any issues there (the reason I use cpp is because
it's
in a big project that needs cpp enabled; it is further linked and so
on).
gcc version used: 4.6.2 (mingw)
cython version used: 0.18 (I did pip install Cython)
python version used: python 2.7.3 (MSC v.1500 32 bit).
Very strange. Does calling PyComplex_AsCComplex directly produce the
same crash? What about
I'm not sure how to call this directly. Do you mean by modifying the
generated cpp file and then manually building an extension module?
cdef complex double x = 1.0
This one works.
or
cdef object py_x = 1.0
cdef complex double x = py_x
This one crashes!
Ah. Try
from cpython.complex cimport Py_complex, PyComplex_AsCComplex
cdef Py_complex x = PyComplex_AsCComplex(py_x)
print x.real, x.imag
Ok. I tried this, and it also crashes. Here's the modification:
from cpython.complex cimport Py_complex
from cpython.complex cimport PyComplex_AsCComplex
@cython.cdivision(True)
cdef public double complex my_func(int a, b):
cdef object py_x = 1.0
#cdef double complex x = 1.0 # Does not crash
#cdef double complex x2 = py_x # Crashes for py_x = 1,
not for py_x=1j.
#cdef Py_complex x = PyComplex_AsCComplex(py_x) # Crashes, even for
py_x=1j
#print x.real, x.imag
And as you can see, the PyComplex_AsCComplex also crashes (SIGSEGV).
I tried to compile with debug information, as in the instructions in
http://docs.cython.org/src/userguide/debugging.html
But I cannot get the line numbers. Probably I need a debug-python version,
but that seems to be very nontrivial on Windows.
Not sure if I can think of other options to test it and/or track down the
bug...
Now it even crashes when py_x = 1j. So maybe there's something else going
wrong here too.
I wonder if it's a compiler miss-match or something like that.
In this case, this causes a significant problem for us. All other code
works as expected, and I'm compiling a very large GCC project which uses
Cython for certain functionality. Switching to the MSC tools would be
quite a pain. I attached the latest version that isolates the bug. Can
you give me directions on how to put this on the tracker as an issue:
- type: defect
- milestone: ?
- keywords: complex, cpp
- priority: for me it is critical (there's a workaround -although it
requires the user to manually add some code)
- component: C++ ?
Is there anything else I could try to resolve/debug this issue? Are
there a debug build binaries of Python available? Apparently, it's not
that easy to find.
Thanks for the help so far!
Martin Fiers
Regards,
Martin
P.S. I only replied to you because you didn't put the
cython-devel@python.org in the previous mail.
Oops. Un-intentional oversight.
from distutils.core import setup
from Cython.Build import cythonize
from distutils.extension import Extension
from Cython.Distutils import build_ext
import os
path = '.'
lib_name = 'complex_double'
full_file ='complex_double.pyx'
additional_include_directories = []
script_args = ["build_ext", "--build-lib", path]
def isWindows():
return os.name=='nt'
if(isWindows()):
script_args.append('--compiler=mingw32')
ext_module = Extension(lib_name,
sources=[full_file],
language="c++",
#extra_compile_args = ["-O0"] # Doesn't work? It just appends it, but we wish to replace it. During production, we want -O2/-O3 and -ffast-math to be enabled
extra_compile_args = ["-ffast-math"],
)
# FIXME: Find the proper way to pass these arguments.
ext_module.cython_gdb = True
#ext_module.cython_create_listing = True
setup(
name = "Cythonized module",
ext_modules = [ext_module],
cmdclass={'build_ext': build_ext},
script_args = script_args,
include_dirs = additional_include_directories,
)
print 'Done'import cython
from cpython.complex cimport Py_complex
from cpython.complex cimport PyComplex_AsCComplex
@cython.cdivision(True)
cdef public double complex my_func(int a, b):
cdef object py_x = 1j
#cdef double complex x = 1.0 # Does not crash
#cdef double complex x2 = py_x # Crashes for py_x = 1, not
for py_x=1j.
#cdef Py_complex x = PyComplex_AsCComplex(py_x) # Crashes, even for py_x=1j
#print x.real, x.imag
if(a==0):
return 1;
else:
return b; # Crashes if b is real.
def my_func_exposed(int a, b):
return my_func(a,b)import complex_double
# The following line does not crash when the second
# argument is a complex value. It crashes when it's real.
print complex_double.my_func_exposed(1,1.0+1j)
print 'Done'
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