Permit src_indices for an input in both group.promotes and group.connect provided that both are flat.

[Kenneth-T-Moore]

Summary

Permit src_indices for an input in both group.promotes and group.connect provided that both are flat. A new cascaded src_indices is computed for the connection.

Related Issues

• Resolves OpenMDAO should allow src_indices to be used on both a promote and a connection to the same input provided that the are both flat src_indices. #1708

Backwards incompatibilities

None

New Dependencies

None

[naylor-b]

Are we really sure that we want to allow users to do this? If we happen to see src_indices specified in multiple places, how can we be sure of the intent? Did they intend to do this sort of nested src_indices thing, or did they just make a mistake?

[Kenneth-T-Moore]

I don't know. There is some risk, but the risk stems from the user not knowing what they are connecting to, and if you are using src_indices, you should know the shape of your target.

Alternative is to make the user create an adapter component.

@robfalck @JustinSGray

[naylor-b]

Or maybe add another metadata entry like 'allow_nested_src_indices' or something so we know the intent.

[Kenneth-T-Moore]

After discussion, we determined a better way to do this inside a dymos model.