array_or_vector-class: Auxiliary Class "array_or_vector"
Description
"array_or_vector" is the class union of
c("array", "matrix", "vector") and exists for its use in
signatures of method definitions.
Arguments
Objects from the Class
A virtual Class: No objects may be
created from it.
Details
Using "array_or_vector" instead of just "vector" in a
signature makes an important difference: E.g., if we had
setMethod(crossprod, c(x="mpfr", y="vector"), function(x,y) CPR(x,y)),
a call crossprod(x, matrix(1:6, 2,3)) would extend into a call
of CPR(x, as(y, "vector")) such that CPR()'s second
argument would simply be a vector instead of the desired
$2\times3$ matrix.