Dear Furuya-san,
Thank you very much for your contributions to the Maxima project!
Diag.mac is clearly a very useful package.
Like all contributions to the Maxima project (and other free software
projects), it is valuable not only as a package in itself, but also as
a base for further development, and as material for cross-pollination
with other pieces of code. Indeed, that is so important that only
contributions using licenses that allow this sort of mixing are
accepted.
I have not looked into the particular case of linear algebra code in
Maxima, but I do know that there are many areas in Maxima where we
need to reorganize and unify existing code from multiple sources.
Your contributions to the code base are greatly appreciated.
Sincerely,
-s