[D] Why Authors Dont Include The Source codes In Their Papers?

Hello,

I am from soft robotics field and I am not really expert in machine learning and I am still trying to understand how machine learning can come up with new designs for composites, meta-materials, this paper doesnot include the source code, for me it is vague how to start since I never did this before, I dont know if anyone familiar with something and open source so that I can start learn and build on.

Thanks

authors machinelearning