How to create a variable of optional type(e.g., Optional[Tuple[int,int]]), with C++ libtorch jit api?

I have a pytorch script which accepts Optional[Tuple[int, int]] as the input. The script is exported to “script.pb”.
Then in C++ api, the script.pb is loaded. But how can I create C++ obj of type Optional[Tuple[int, int]]? Is there any documentation?

Looks like there was a bug exposed by this use case…, the following will apply once this fix is merged.

Our C++ value type (IValue) doesn’t have any concept of optional/not, it is either some concrete value (e.g. Tuple[int, int]) or None. Only the JIT’s type system knows what things can be optional. You can see a small example of how to construct one here.

The C++ API tests may also be helpful.

@driazati let’s make an issue tracking improved C++ API documentation, especially of IValues, etc… I’m seeing a lot of questions on it, and what we have now is not great.

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Just curious, in which case you need to create C++ obj of optional type? I think if you have Optional[Tuple[int, int]], you can always pass concrete objs into.

There is already an issue open,