CODEWITHSUNDEEP
pythonc++importcython
Ivan
Ivan

Reputation: 11

Cython promlem: cimport libcpp.vector not compiled

I'm trying to use cython to speed up my code. Since I'm working with an array of strings, I want to use string and vector from c++. But I have problems compiling if I import c libraries. For an example, I tried to implement an example from here: https://cython.readthedocs.io/en/latest/src/tutorial/cython_tutorial.html. So, my code is

from libcpp.vector cimport vector

def primes(unsigned int nb_primes):
    cdef int n, i
    cdef vector[int] p
    p.reserve(nb_primes)  # allocate memory for 'nb_primes' elements.

    n = 2
    while p.size() < nb_primes:  # size() for vectors is similar to len()
        for i in p:
            if n % i == 0:
                break
        else:
            p.push_back(n)  # push_back is similar to append()
        n += 1

    # Vectors are automatically converted to Python
    # lists when converted to Python objects.
    return p

I save thiscode like 'test_char.pyx'. For compilation i use it:

from Cython.Build import cythonize
setup(name='test_char',
      ext_modules = cythonize('test_char.pyx')
      )

After that i get test_char.c, but i don't get test_char.py. If i will use this code (without cimport):

def primes(int nb_primes):
    cdef int n, i, len_p
    cdef int p[1000]
    if nb_primes > 1000:
        nb_primes = 1000
    len_p = 0  # The current number of elements in p.
    n = 2
    while len_p < nb_primes:
        # Is n prime?
        for i in p[:len_p]:
            if n % i == 0:
                break

        # If no break occurred in the loop, we have a prime.
        else:
            p[len_p] = n
            len_p += 1
        n += 1

    # Let's return the result in a python list:
    result_as_list  = [prime for prime in p[:len_p]]
    return result_as_list

all be right. So, plz, any ideas?

Upvotes: 0

Views: 412

Answers (1)

Ivan
Ivan

Reputation: 11

from distutils.extension import Extension
extensions = [
    Extension("test_char", ["test_char.pyx"]
              , language="c++"
              )
]
setup(
    name="test_char",
    ext_modules = cythonize(extensions),
)

it can solve this problem

Upvotes: 1

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