str = mat2str(A) converts fi object A to
a string representation. The output is suitable for input to the eval function such that eval(str) produces
the original fi object exactly.
str = mat2str(A,
'class') creates a string representation with the name
of the class of A included. This option ensures
that the result of evaluating str will also contain
the class information.
str = mat2str(A, n,
'class') uses n bits of precision and
includes the class of A.