alt_eigen more info

Yes, setting `ratmx : false' eliminates the failures in
all the platforms I tested:

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Host type: i686-pc-mingw32

Maxima version: 5.25.1
Lisp implementation type: Clozure Common Lisp
Lisp implementation version: Version 1.7-r14925M (WindowsX8632)

Maxima version: 5.28.0-2
Lisp implementation type: GCL
Lisp implementation version: 2.6.8

------------------------------------------
Maxima version: "5.28.0"
Host type: "x86_64-unknown-linux-gnu"

Lisp implementation type: "SBCL"
Lisp implementation version: "1.0.57.0.debian"

Lisp implementation type: "CLISP"
Lisp implementation version: "2.49 (2010-07-07) (built 3538483872) 
(memory 3562145853)"

Lisp implementation type: "CMU Common Lisp"
Lisp implementation version: "20c release-20c (20C Unicode)"

Lisp implementation type: "GNU Common Lisp (GCL)"
Lisp implementation version: "GCL 2.6.7"

Lisp implementation type: "ECL"
Lisp implementation version: "11.1.1"

Lisp implementation type: "Clozure Common Lisp"
Lisp implementation version: "Version 1.8-r15286M  (LinuxX8664)"
------------------------------------------