cartographer
cartographer copied to clipboard
cartographer-project
Cartographer is effectively GPL because of Ceres -> SuiteSparse dependency
In https://github.com/cartographer-project/cartographer/issues/971, the following was noticed:
When libsuitesparse-dev is not installed, (Ceres) optimization will take >100 times longer.
It would nice to warn about this.
Building Cartographer was then switched to require Ceres with SuiteSparse in https://github.com/cartographer-project/cartographer/pull/189.
However, a component of SuiteSparse, CHOLMOD/Supernodal, is licensed under GPL. Effectively, this turn Ceres, Cartographer and all other software that builds upon it to be GPL licensed.
More information in: https://github.com/ceres-solver/ceres-solver/issues/1026
In order for Cartographer to be GPL-free, Ceres either needs to use a GPL-free sparse linear algebra backend (as described in https://github.com/ceres-solver/ceres-solver/issues/1026); or Cartographer needs to be switched to another solver for solving the pose graph optimization problem.
The Ceres scan matcher in LocalTrajectoryBuilder is fine; it does not need a sparse solver. The OptimizationProblem in PoseGraph needs a sparse solver.
