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from __future__ import division, absolute_import, print_function
import numpy as np
from numpy.testing import TestCase
ndims = 2
size = 10
shape = tuple([size] * ndims)
def _indices_for_nelems(nelems):
"""Returns slices of length nelems, from start onwards, in direction sign."""
if nelems == 0:
return [size // 2] # int index
res = []
for step in (1, 2):
for sign in (-1, 1):
start = size // 2 - nelems * step * sign // 2
stop = start + nelems * step * sign
res.append(slice(start, stop, step * sign))
return res
def _indices_for_axis():
"""Returns (src, dst) pairs of indices."""
res = []
for nelems in (0, 2, 3):
ind = _indices_for_nelems(nelems)
# no itertools.product available in Py2.4
res.extend([(a, b) for a in ind for b in ind]) # all assignments of size "nelems"
return res
def _indices(ndims):
"""Returns ((axis0_src, axis0_dst), (axis1_src, axis1_dst), ... ) index pairs."""
ind = _indices_for_axis()
# no itertools.product available in Py2.4
res = [[]]
for i in range(ndims):
newres = []
for elem in ind:
for others in res:
newres.append([elem] + others)
res = newres
return res
def _check_assignment(srcidx, dstidx):
"""Check assignment arr[dstidx] = arr[srcidx] works."""
arr = np.arange(np.product(shape)).reshape(shape)
cpy = arr.copy()
cpy[dstidx] = arr[srcidx]
arr[dstidx] = arr[srcidx]
assert np.all(arr == cpy), 'assigning arr[%s] = arr[%s]' % (dstidx, srcidx)
def test_overlapping_assignments():
"""Test automatically generated assignments which overlap in memory."""
inds = _indices(ndims)
for ind in inds:
srcidx = tuple([a[0] for a in ind])
dstidx = tuple([a[1] for a in ind])
yield _check_assignment, srcidx, dstidx
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