Optimization on manifolds is a versatile framework for continuous optimization.
It encompasses optimization over vectors and matrices,
and adds the possibility to optimize over curved spaces to handle constraints and symmetries such as orthonormality, low rank, positivity and invariance under group actions.
Manopt makes it easy.
Matlab 
This website is the home of the Matlab version of Manopt. Install from downloads or from our GitHub repository, then run a first example.
Python 
The PyManopt website houses the Python version of Manopt and its documentation. Also check out the GitHub repository.
Julia 
The Manopt.jl website hosts the Julia version of Manopt and its documentation. The GitHub repository has both Manopt.jl and Manifolds.jl.