I am trying to use R to calculate eigenvalues (possibly for matrices of sizes 5x5 or 6x6 as computational exercise).

Can't locate object method "make" via package "Math::Complex" (perhaps you forgot to load "Math::Complex"?) at /usr/share/perl/5.30/Math/Complex.pm line 329 Died within Math::Complex::cplx called at line 351 of /usr/local/share/perl/5.30.0/Statistics/R/IO/QapEncoding.pm from within Statistics::R::IO::QapEncoding::decode called at line 236 of /usr/local/share/perl/5.30.0/Statistics/R/IO/Rserve.pm from within Statistics::R::IO::Rserve::eval called at line 26 of [PG]/lib/Rserve.pm from within Rserve::try_eval called at line 146 of [PG]/macros/RserveClient.pl from within main::rserve_eval called at line 40 of (eval 4456)