ImportError: Cannot load dynamic library. Did you compile FLANN?

You install pyflann as :

sudo pip install pyflann

and after that, test it via ipython

import pyflann

it says you have NOT compile flann. As follows:

In [1]: import pyflann
---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
<ipython-input-1-b6d4c333a325> in <module>()
----> 1 import pyflann

/usr/local/lib/python2.7/dist-packages/pyflann/__init__.py in <module>()
25 #THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
---> 27 from index import *
28 from io.dataset import load, save
29 try:

/usr/local/lib/python2.7/dist-packages/pyflann/index.py in <module>()
25 #THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
---> 27 from bindings.flann_ctypes import *
28 from io.dataset import *
29 import numpy.random as _rn

/usr/local/lib/python2.7/dist-packages/pyflann/bindings/__init__.py in <module>()
28 #from pyflann_parameters import parameter_list, algorithm_names
29 #from pyflann_parameters import centers_init_names, log_level_names
---> 30 from flann_ctypes import *

/usr/local/lib/python2.7/dist-packages/pyflann/bindings/flann_ctypes.py in <module>()
171 flannlib = load_flann_library()
172 if flannlib == None:
--> 173     raise ImportError('Cannot load dynamic library. Did you compile FLANN?')
174
175

ImportError: Cannot load dynamic library. Did you compile FLANN?

Deep in /usr/local/lib/python2.7/dist-packages/pyflann/lib/linux/libflann.so and you will find a libflann.so already exists. BUT it’s size is 0, that’s empty library.

Now compile a flann step by step:

1.download from HERE

2.extract it

unzip flann-1.8.4-src.zip

3.make

cd flann-1.8.4-src
mkdir build
cd build
cmake ..
make -j8

4.cp flann-1.8.4-src/build/lib/libflann.so into /usr/local/lib/python2.7/dist-packages/pyflann/lib/linux/libflann.so

sudo cp lib/libflann.so /usr/local/lib/python2.7/dist-packages/pyflann/lib/linux/libflann.so

5.re-try import pyflann now.