Upd os4.x

[modenaxe]

@eravera @darios93
I have upgraded a bit the project:

• created a neat function to replace body.getJoint() in OpenSim 4.0
• made the tool compatible with both OpenSim 3.3 and 4.x
• update the tests (OpenSim 4.0 gives slightly different results)
  Would you mind give it a run on your machine and confirm that everything works well before I merge on main?
  Thank you,
  Luca

[modenaxe]

@Dario93 thank you for the email, that was helpful! Could you give it another try with the new code I added?

[eravera]

Hi @modenaxe,

I'm sorry for the delay but I needed to install MATLAB in my laptop again.

I can run without problem the new version of the scripts. I also note lite differences in results but they are similar at differences presented in Python version. I think these differences could be due to algorithms used to solve the system Ax=b.

In addition, other difference between Python and Matlab version is in fval because I used mean squared error instead of sum of squared errors.

Emi

[modenaxe]

@eravera thank you - I feel bad I wasted your time and space drive reinstalling MATLAB!

You are right, I also noted a difference in the results from 4.0, which is why I modified the reference model for the tests.

I will double check one last time (getOpenSimVersion() is not very robust yet) and merge the pull request.

[modenaxe]

@eravera do you think the different objective function makes a large difference? (worth spending time on it?)

[eravera]

@modenaxe , don't worry, installing MATLAB was not a problem for me.
Regarding differences in solutions between python and MATLAB algorithms used to solve the optimization problem, I think that they are not representative and we are not worth spending time for this because they are less than 0.005%.

On the other hand, I think that we will have no problem between OpenSin versions in the python script due to the fact that I have generated functions to extract the joint's features reading the model.osim as xml file directly. However, of course, you feel free to tell me if you want me to change any of this.

[modenaxe]

@eravera that's a good solution. For the MATLAB version instead I have written a function getBodyJoint that replaced the old and deeply missed aBody.getJoint() function. I am mentioning it in case it's helpful for other projects.