boolean_idx.py

from __future__ import print_function
import torch

A = torch.rand(4, 4)
An = A.numpy()

idx = torch.ByteTensor([1, 0, 0, 1])
idxn = [True, False, False, True]

# Numpy indexing.
print('numpy')
print(An[idxn].shape)
print(An[:, idxn].shape)

# Torch indexing.
print('torch')
print(A[idx].size())
print(A[:, idx].size())

# Output.
"""
numpy
(2, 4)
(4, 2)
torch
Traceback (most recent call last):
  File "bug.py", line 17, in <module>
    print(A[idx].size())
RuntimeError: inconsistent tensor size, expected src [4 x 4] and mask [4] to have the same number of elements, but got 16 and 4 elements respectively at /Users/soumith/miniconda2/conda-bld/pytorch_1501999754274/work/torch/lib/TH/generic/THTensorMath.c:197
"""