How to write own cost function in c++?

[yrik]

Thank you for the great project.
My questions is, how to write own cost function with c++? I have visual and inertial data.

[sarlinpe]

We have some visual cost functions in COLMAP: https://github.com/colmap/colmap/blob/main/src/colmap/estimators/cost_functions.h There is also a pending PR for inertial optimization: colmap/colmap#2561