`subs` and `evalf` is simply not the right tool for float/double precision arithmetics. `subs` in particular is a general tool for symbolic substitutions, and i

`subs` and `evalf` is simply not the right tool for float/double precision arithmetics. `subs` in particular is a general tool for symbolic substitutions, and it is not fair to expect it to be fast for numerics (although improvements would always be great). `evalf` provides high precision arithmetics (your RAM is the limit), so again, it is inherently slower than float math. One can argue that this should be documented better or that the tool should be able to guess the intent of the user, but otherwise I would say of course `subs` and `evalf` are slow when you use them for float math.