CODEWITHSUNDEEP
pythonc++arraysnumpyswig
Otherness
Otherness

Reputation: 405

How to use numpy.i in swig?

I'm trying to wrap some c++ code with python using swig and I need to send NumPy arrays into the c++ vector class for some processing.

My problem is that I don't seem to be able to access "numpy.i" in my swig .i file.

How can I import/include numpy.i?

add_vector.i

%module add_vector
%{
    #define SWIG_FILE_WITH_INIT
    #include "add_vector.h"
%}

%include "numpy.i"

%init %{
import_array();
%}

%include std_vector.i
%template(vecInt) std::vector<int>;

%include "add_vector.h"

Makefile

all:
rm -f *.so *.o *_wrap.* *.pyc *.gch add_vector.py
swig -c++ -python add_vector.i
g++ -O0 -g3 -fpic -c add_vector_wrap.cxx add_vector.h add_vector.cpp -I/home/tools/anaconda3/pkgs/python-3.7.3-h0371630_0/include/python3.7m/
g++ -O0 -g3 -shared add_vector_wrap.o add_vector.o -o _add_vector.so

tester.py

import add_vector as vec 
import numpy as np

a = np.array([1,2,3])
b = np.array([4,5,6])
c = np.empty(len(a))

vec.add(c,a,b)

print('c:', c)

Output:

rm -f *.so *.o *_wrap.* *.pyc *.gch add_vector.py
swig -c++ -python add_vector.i
add_vector.i:7: Error: Unable to find 'numpy.i'
Makefile:2: recipe for target 'all' failed
make: *** [all] Error 1

I'm using debian, in case that matters.

Thanks!

Upvotes: 1

Views: 1446

Answers (1)

Jonathan
Jonathan

Reputation: 734

Copy numpy.i into the same folder as add_vector.i.

Or use the command line option -lifile and give it the path to your numpy.i file.

swig -l/path/to/numpy.i ...

For a list of SWIG command line options, see http://www.swig.org/Doc3.0/SWIGDocumentation.html#SWIG_nn2

Upvotes: 2

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