Build fails with `GTSAM_TANGENT_PREINTEGRATION` off

[p-zach]

Description

When building with GTSAM_TANGENT_PREINTEGRATION off, the build fails because preintegrated() is not a member of PreintegratedImuMeasurements, which the compiler discovers upon creating navigation.cpp from navigation.i. It is not a member because it doesn't exist in ManifoldPreintegration, which PreintegratedImuMeasurements inherits from instead of TangentPreintegration (where preintegrated() does exist) when GTSAM_TANGENT_PREINTEGRATION is off.

Steps to reproduce

1. Set up GTSAM to build Python wrapper
2. Turn off GTSAM_TANGENT_PREINTEGRATION
3. Try to build

Expected behavior

The build succeeds.

Environment

• Windows 10
• Python 3.11
• GTSAM 4.3a0

Additional information

My current solution is commenting out the preintegrated() line:

gtsam/gtsam/navigation/navigation.i

Line 168 in ce5f93f

gtsam::Vector preintegrated() const;

Permanent solutions would be either providing a real or dummy implementation in ManifoldPreintegration or officially removing preintegrated() from navigation.i.

[dellaert]

I think, with the plethora of new integration methods coming, we should actually use a template argument to decide between integration methods. I'll look into this.