Hello,
When constructing (or accessing) matrix elements, I'd like to be able to call a function which does bounds-checking (and in the case of assignment, reference-count-checking with an exception if there's more than one reference) only when debugging options are turned on.
I'm proposing adding these checks to the xelem method instead of creating a new method for it. I can't imagine why it's necessary to have a method that does "no checks of any kind ever! Not even when debugging!"