Using Cython to wrap a c++ template to accept any numpy array

Question

I\'m trying to wrap a parallel sort written in c++ as a template, to use it with numpy arrays of any numeric type. I\'m trying to use Cython to do this.

My problem

Answer 1

Yes, you want to use a fused type to have Cython call the sorting template for the appropriate specialization of the template. Here's a working example for all non-complex data types that does this with std::sort.

# cython: wraparound = False
# cython: boundscheck = False

cimport cython

cdef extern from "<algorithm>" namespace "std":
    cdef void sort[T](T first, T last) nogil

ctypedef fused real:
    cython.char
    cython.uchar
    cython.short
    cython.ushort
    cython.int
    cython.uint
    cython.long
    cython.ulong
    cython.longlong
    cython.ulonglong
    cython.float
    cython.double

cpdef void npy_sort(real[:] a) nogil:
    sort(&a[0], &a[a.shape[0]-1])