Using a publicly available code and modifying it to my PhD thesis. Should it be cited in the paper if I have modified the core equation? I have proposed a new equation and will be implementing it into a publicly available code in the thesis. I have modified the core equation of the program (the main constitutive equation, &quot;Johnson Cook Model&quot;), while the numerical method (newton-raphson solver) is as implemented by the original author.
I would cite the original authors in my PhD thesis where I will explicitly talk about the functioning of the code. However, my journal paper would be only about the equation (as it is the highlight of the work) and the implementation is not the main focus. I will not talk about the implementation and just mention that the &quot;equation was implemented using a VUMAT.&quot;
In that case, do I have to cite the original source in the paper when I would eventually submit to a journal?
If you borrowed something from another source and modified it, you should definitely cite the original source in your paper.