_random_betweenness_cast.pyx

from RandomBetweennessCast cimport RandomBetweennessCast
from cpython.long cimport PyLong_AsVoidPtr
import numpy as np

from libcpp.vector cimport vector

# Create a Cython extension type which holds a C++ instance
# as an attribute and create a bunch of forwarding methods
# Python extension type.
# Where an array need only be iterated over sequentially, a pointer to its
# first element should be assigned as an attribute to the c_cast object. Only
# when its elements need to be accessed in a discontinous manner should the
# attribute be set as a std::vector
cdef class PyCast:
    cdef RandomBetweennessCast c_cast  # Hold a C++ instance which we're wrapping
    
    def __init__(self, long long ptr):
        self.c_cast = RandomBetweennessCast()
        self.c_cast.G_ptr = PyLong_AsVoidPtr(ptr)

    def random_betweenness_compute(self, long[:] sources,
                                    long[:] targets, int num_edges,
                                   double[:] weights):

        self.c_cast.sources_len = <long>len(sources)
        self.c_cast.targets_len = <long>len(targets)
        
        cdef vector[int] sources_vec
        cdef vector[int] targets_vec

        for i in range(len(sources)):
            sources_vec.push_back(sources[i])
        for i in range(len(targets)):
            targets_vec.push_back(targets[i])
        self.c_cast.sources = sources_vec
        self.c_cast.targets = targets_vec

        cdef double[:] weights_memview = weights
        self.c_cast.weights_ptr = &weights_memview[0]

        self.c_cast.random_betweenness_compute()

        
    @property
    def random_betweenness(self):
        _random_betweennesses = np.zeros((self.c_cast.num_edges),
                                          dtype=np.double)
        for i in range(self.c_cast.num_edges):
            _random_betweennesses[i] = self.c_cast.betweennesses[i]

        return _random_betweennesses