File: memview_to_c.pyx

package info (click to toggle)
cython 0.29.32-2
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 15,028 kB
  • sloc: python: 67,518; ansic: 14,866; cpp: 1,340; xml: 1,031; makefile: 393; lisp: 206; sh: 137; sed: 11
file content (28 lines) | stat: -rw-r--r-- 764 bytes parent folder | download | duplicates (4)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
cdef extern from "C_func_file.c":
    # C is include here so that it doesn't need to be compiled externally
    pass

cdef extern from "C_func_file.h":
    void multiply_by_10_in_C(double *, unsigned int)

import numpy as np

def multiply_by_10(arr): # 'arr' is a one-dimensional numpy array

    if not arr.flags['C_CONTIGUOUS']:
        arr = np.ascontiguousarray(arr) # Makes a contiguous copy of the numpy array.

    cdef double[::1] arr_memview = arr

    multiply_by_10_in_C(&arr_memview[0], arr_memview.shape[0])

    return arr


a = np.ones(5, dtype=np.double)
print(multiply_by_10(a))

b = np.ones(10, dtype=np.double)
b = b[::2]  # b is not contiguous.

print(multiply_by_10(b))  # but our function still works as expected.