Support multiple indices for aten::index.Tensor

[ruoqianguo]

Signed-off-by: Ruoqian Guo ruoqiang@nvidia.com

Description

Support multiple indices for aten::index.Tensor.
In Pytorch, aten::index.Tensor can receive several indices, like this:

x = torch.rand(5, 7, 10)
idx0 = torch.tensor([0, 0, 0, 0])
idx1 = torch.tensor([1, 1, 1, 1])
idx2 = torch.tensor([2, 2, 2, 2])
y1 = x[idx0, idx1, idx2] # result is like tensor([x[0, 1, 2], x[0, 1, 2], x[0, 1, 2], x[0, 1, 2]])
y2 = x[idx0] # result is like tensor([x[0, :, :], x[0, :, :], x[0, :, :], x[0, :, :]])

Previous, we only support one indice in PR #921 . Now we support serval indices for aten::index.Tensor.

Fixes #1274

Type of change

Please delete options that are not relevant and/or add your own.

• New feature (non-breaking change which adds functionality)

Checklist:

• My code follows the style guidelines of this project (You can use the linters)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas and hacks
• I have made corresponding changes to the documentation
• I have added tests to verify my fix or my feature
• New and existing unit tests pass locally with my changes
• I have added the relevant labels to my PR in so that relevant reviewers are notified

[narendasan]

LGTM