I am now trying to provide information about julia (performance issues, project worfkflow) here. This is meant as a additional information for those of you interested in these questions.
How to estimate eigenvalues from matrix entries
Matrices and graphs
Application to Jacobi iteration
Pluto notebook: pluto/julia, html, pdf
Diagonally dominant matrices
M-Matrices
Pluto notebook: pluto/julia, html, pdf
Comparison between iterative methods
Pluto notebook: pluto/julia, html, pdf