Many engineering problem appears with complex arguments.
It is indeed possible to convert the complex formulation into its real counterpart.
However, it is convenient to directly deal with the complex formulation.
I think it would be nice to add some complex counterpart of real manifold factory to Manopt. More researchers will benefit from it.
List some complex manifold as follows:
complex oblique
complex elliptope
complex spectrahedron
Hermitte positive definite matrices
Above complex manifolds appear frequently in beamforming vector or covariance matrix design problems.