Negative values in LongTensor indexing not work

1 
a = torch.Tensor([1,2,3])
a[-1]  # works, 3
a[[0,1]]  # works, 1,2
a[[-1,0]]  # not work, raise RuntimeError: index out of range

It would be nice to also support negative values in LongTensor indexing.

2

Right now it works if you wrap a in a Variable:

a = Variable(torch.randn(5))
a[[-1, 0]]

There are plans to merge Variable and Tensor for a more unified API. When that happens, negative values in LongTensors will be supported.

3

@richard

Running:

import torch
from torch.autograd import Variable

a = Variable(torch.randn(5))
a[[-1, 0]]

Results in an error:

    a[[-1, 0]]
  File "/usr/local/lib/python2.7/dist-packages/torch/autograd/variable.py", line 78, in __getitem__
    return Index.apply(self, key)
  File "/usr/local/lib/python2.7/dist-packages/torch/autograd/_functions/tensor.py", line 87, in forward
    result = i.index(ctx.index)
RuntimeError: index out of range at /pytorch/torch/lib/TH/generic/THTensorMath.c:277