This **roughly** corresponds to Goal 3.2 in https://docs.google.com/document/d/1iiLNwR5ohAsw_ymfnOpDsyF6L9RTUaHMpD8YLw-jxEw/edit#
Namely:
It adds the following:
* SymbolicIntNode interface
* LazySymbolicIntNode implementation
* Lazy `narrow_copy` implementation
* Need add support for SymInt in codegen
* Test (below)
```cpp
TEST(LazyDynamicOpsTest, NarrowCopy) {
auto x = torch::rand({5, 10, 10}).to(kLazy);
const size_t Y_DIM = 3;
const size_t X_DIM_INDEX = 2;
auto y = torch::rand({Y_DIM}).to(kLazy);
auto ly = torch::lazy::TryGetLtcTensor(y);
auto dim_node = MakeNode<SizeNode>(ly->GetIrValue(), 0);
auto lmn = new torch::lazy::SymbolicIntNode(dim_node);
auto z = x.narrow_copy(X_DIM_INDEX, 0, lmn->toSymInt());
AllClose(z.cpu(), x.cpu().narrow_copy(X_DIM_INDEX, 0, Y_DIM));
}
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75759
Approved by: https://github.com/wconstab
Summary:
Next stage of breaking up https://github.com/pytorch/pytorch/pull/74710
Move shape cache implementation to the backend interface. Also, clean up some of the hashing logic in the base node class.
CC: wconstab JackCaoG henrytwo
Partially Fixes https://github.com/pytorch/pytorch/issues/74628
Pull Request resolved: https://github.com/pytorch/pytorch/pull/75324
Reviewed By: anjali411
Differential Revision: D35730823
Pulled By: wconstab
fbshipit-source-id: cf6fa326319b9324e5f422a78817b6fb5bf7e9b8
(cherry picked from commit faec5043df56639e2fd23de2d91ae796e4f3df70)
