Referring to the GPL3.0-licensed OSS

[Yuto Shirai]

Hello.
Thanks for the great work.

You are using the following as a reference, but studywolf's control is GPL-licensed, is that ok?(It looks like an algorithmic copy, not a code copy.)

  """ iterative Liner Quadratique Regulator
    Ref:
        Tassa, Y., Erez, T., & Todorov, E. (2012). . In 2012 IEEE/RSJ International Conference on
        Intelligent Robots and Systems (pp. 4906-4913). and Study Wolf,
        https://github.com/studywolf/control
    """

https://github.com/Shunichi09/PythonLinearNonlinearControl/blob/master/PythonLinearNonlinearControl/controllers/ilqr.py#L17

This project was personally developed, so it doesn't sound like you did the "clean room design"...

[Shunichi09]

Thank you for pointing out. Did you mean I have to use the GPL-licensed, not MIT-licensed ??

[Yuto Shirai]

Your codes of ilqr and ddp written with reference to the GPL licensed OSS must be licensed under the GPL, but you are not required to make all your software be GPL.

You need to specify the licenses individually as follows
https://github.com/RainerKuemmerle/g2o

License

g2o is licensed under the BSD License. However, some libraries are available under different license terms. See below.

The following parts are licensed under LGPL3+:

    csparse_extension

The following parts are licensed under GPL3+:

    g2o_viewer
    g2o_incremental
    slam2d_g2o (example for 2D SLAM with a QGLviewer GUI)

[Yuto Shirai]

If you make a program using GPL-licensed code, you have to publish all of that code, and companies don't like to use the GPL license.
Your OSS has a lot of stars in it.
If you keep this repository intact, many people could unknowingly slip the GPL license into their product, which would cause a lot of problems for many people.

[Shunichi09]

I'm sorry for the late reply. I really appreciate your pointing out and kindness.
I've fixed my license status!! Please check it.