I would like to understand more details about the implementation of Algebraic Multigrid Methods (AMG). I have been reading "A Multigrid Tutorial", which is quite good and explain all the details of the interpolation, coarse-grid operator and coarse grid selection for AMG. However, I think, there is nothing like playing around and reading a code.
So, I would like to ask if anyone knows any classical AMG "example code", like the geometric multigrid FORTRAN code available at the end of "Multigrid Methods" (SIAM) by S. F. McCormick. It is quite hard to get a high quality and production code like BoomerAMG to learn more about the method.