CAS simplifying non-zero expressions to 0

[Nigel (UK)]

I've noticed this before. As a physicist small numbers are a completely normal part of my work and are not an indication of rounding error. I find this behaviour a real obstacle to whole-heartedly embracing the Prime in my teaching and to recommending it to my physics students. To work around it, you can replace approximate numbers by exact numbers (e.g., write 663/100 * 10^{-34} for Planck's constant) or use symbols that you then substitute numerical values for at the end of a calculation, but neither approach is anywhere near convenient in all circumstances.

I would really like to see this truncation of small quantities as an optional function to be applied when and if I choose to do so (like Chop[] in Mathematica, if my memory serves me correctly). I think it is no more logical to replace small numbers by zero by default than it is to replace numbers greater than three by the string "many"!

Sorry to be unhelpful.

Nigel (UK)