Python 2.7 and Cython: global name col2im_6d_cython is not defined

Question

I have a problem with python 2.7 and Cython on Ubuntu 16.04. I am trying to run code from the cs231n course (Convolutional Neural Networks). But the only function col2im_6d_cython does not work. The error is:

NameError: global name 'col2im_6d_cython' is not defined

The function col2im_6d_cython is defined in im2col_cython.pyx :

def col2im_6d_cython(np.ndarray[DTYPE_t, ndim=6] cols, int N, int C, int H, int W,
        int HH, int WW, int pad, int stride):
    cdef np.ndarray x = np.empty((N, C, H, W), dtype=cols.dtype)
    cdef int out_h = (H + 2 * pad - HH) / stride + 1
    cdef int out_w = (W + 2 * pad - WW) / stride + 1
    cdef np.ndarray[DTYPE_t, ndim=4] x_padded = np.zeros((N, C, H + 2 * pad, W + 2 * pad),
                                                         dtype=cols.dtype)

    col2im_6d_cython_inner(cols, x_padded, N, C, H, W, HH, WW, out_h, out_w, pad, stride)

    if pad > 0:
        return x_padded[:, :, pad:-pad, pad:-pad]
    return x_padded 

The file where col2im_6d_cython is called from is fast_layers.py :

from cs231n.im2col_cython import col2im_cython, im2col_cython
from cs231n.im2col_cython import col2im_6d_cython

def conv_backward_strides(dout, cache):
        x, w, b, conv_param, x_cols = cache
    stride, pad = conv_param['stride'], conv_param['pad']

    N, C, H, W = x.shape
    F, _, HH, WW = w.shape
    _, _, out_h, out_w = dout.shape

    db = np.sum(dout, axis=(0, 2, 3))

    dout_reshaped = dout.transpose(1, 0, 2, 3).reshape(F, -1)
    dw = dout_reshaped.dot(x_cols.T).reshape(w.shape)

    dx_cols = w.reshape(F, -1).T.dot(dout_reshaped)
    dx_cols.shape = (C, HH, WW, N, out_h, out_w)
    dx = col2im_6d_cython(dx_cols, N, C, H, W, HH, WW, pad, stride)

    return dx, dw, db

col2im_cython and im2col_cython work properly, but only col2im_6d_cython does not work.

It seems to me that there is a problem with Cython installation. I've installed it by running: python setup.py build_ext --inplace

setup.py is:

from distutils.core import setup
from distutils.extension import Extension
from Cython.Build import cythonize
import numpy

extensions = [
Extension('im2col_cython', ['im2col_cython.pyx'],
        include_dirs = [numpy.get_include()]
),
]

setup(
    ext_modules = cythonize(extensions),
)

And I had a warning when installing Cython:

Warning: Extension name 'im2col_cython' does not match fully qualified name 'cs231n.im2col_cython' of 'im2col_cython.pyx'
running build_ext

Why does only col2im_6d_cython not work? Are there any ways to fix it?

Thank you all in advance!

Answer 1

The problem solved by uninstalling Anaconda3 completely and installing Anaconda2. Then I've created new environment and reinstalled all needed packages. The error does not appear now