Please consider to supply a bit more context
- which blog post of Mr Trott do you refer to
- which warnings do you see ...
to get a better answer. Quite often this helps
- an educated use of
Evaluate[]
- redefining a function from
f[x_, y_, z_, ...] into f[x_?NumericQ, y_?NumericQ, z_?NumericQ, ...] as far as it is sure that
$x, y, z$ are intended to be numrical: NumericQ
