%%cython magic gives ImportError: dlopen(long_file_name.so, 2): image not found

[gitdoc]

OS X, 10.7. I've been going through the first several cython examples in the cython tutorial, and all of the tutorial examples work correctly for me thus far.

However, when I try to do what Fernando did in his Science And Python presentation at Pycon Canada (at playback position 37:42), I get a strange error. The code is:

%load_ext cythonmagic
%%cython
cdef double fcy(double x) except? -2:
    return x**2-x

def integrate_fcy(double a, double b, int N):
    cdef int i
    cdef double s, dx
    s = 0; dx = (b-a)/N
    for i in range(N):
    s += fcy(a+i*dx)
    return s * dx

The notebook output:

---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
 in ()
----> 1 get_ipython()._run_cached_cell_magic('cython', '')

/usr/local/lib/python3.2/site-packages/IPython/core/interactiveshell.py in _run_cached_cell_magic(self, magic_name, line)
   2513         cell = self._current_cell_magic_body
   2514         self._current_cell_magic_body = None
-> 2515         return self.run_cell_magic(magic_name, line, cell)
   2516 
   2517     def run_cell(self, raw_cell, store_history=False, silent=False):

/usr/local/lib/python3.2/site-packages/IPython/core/interactiveshell.py in run_cell_magic(self, magic_name, line, cell)
   2092             magic_arg_s = self.var_expand(line, stack_depth)
   2093             with self.builtin_trap:
-> 2094                 result = fn(line, cell)
   2095             return result
   2096 

/usr/local/lib/python3.2/site-packages/IPython/extensions/cythonmagic.py in cython(self, line, cell)

/usr/local/lib/python3.2/site-packages/IPython/core/magic.py in (f, *a, **k)
    190     # but it's overkill for just that one bit of state.
    191     def magic_deco(arg):
--> 192         call = lambda f, *a, **k: f(*a, **k)
    193 
    194         if isinstance(arg, collections.Callable):

/usr/local/lib/python3.2/site-packages/IPython/extensions/cythonmagic.py in cython(self, line, cell)
    187             self._code_cache[key] = module_name
    188 
--> 189         module = imp.load_dynamic(module_name, module_path)
    190         self._import_all(module)
    191 

ImportError: dlopen(/Users/lab/.ipython/cython/_cython_magic_0e71fc3338606be06aed17a605e60bbd.cpython-32m.so, 2): image not found

This is the output in the Terminal that I used to start the IPython notebook session:

/Users/lab/.ipython/cython/_cython_magic_e9a2648cd85a2b3bce8e97b6bbc5f379.c:467:15: warning: 
      unused function
      '__pyx_f_46_cython_magic_e9a2648cd85a2b3bce8e97b6bbc5f379_fcy'
      [-Wunused-function]
static double __pyx_f_46_cython_magic_e9a2648cd85a2b3bce8e97b6bbc5f379_fcy(...
              ^
1 warning generated.

This worked ok for me, but not the %%cython magic above:

a=10
b=20

%%cython_inline
return a+b

Compiling /Users/lab/Library/Caches/cython/inline/_cython_inline_074486d5a226d2c163f10589ac495ca2.pyx because it changed.
Cythonizing /Users/lab/Library/Caches/cython/inline/_cython_inline_074486d5a226d2c163f10589ac495ca2.pyx
Out[52]: 30

[minrk]

Hm, seems to be a Python3 issue. What do you get from

iptest3 IPython.extensions

?

[minrk]

No response for five months, closing as stale. Feel free to reopen with more information.