CAS and small numbers

[Tugdual]

(04-22-2014 09:19 PM)Nigel (UK) Wrote:  

(04-22-2014 08:53 PM)Han Wrote:  Rather than converting yourself, have the calculator do it. For example, for 6.626e^-34, I would type (in CAS) 6.626, hit the [ENTER] key and then the [a b/c] key, and then type * 10^(-34). Then store that using the STO menu key to whatever variable you wanted.

If you hit the [a b/c] key with the exact result, it will convert it to scientific notation.

Thanks for this idea. What I've done now is to define a function exeex (exact exponent):

(a,b) -> exact(a)*10^b

This lets me enter exact powers of ten inline, which is workable.

I still think Xcas would be more useful to scientists if this feature was reconsidered, or its implementation was changed in some way. Perhaps setting small values to zero could be separated out from the default "simplify" routine, rather like "Chop" in Mathematica?

Nigel (UK)[/font]

I agree, the mitigation given by Han is too tricky to be convenient.
I recently used the prime for some matrices calculation (very nice and convenient!) but for the rest I tend to be faster on the 34s or the 15C because of those so many glitches that still make the Prime not trustable. I heard of an update which is excellent news, totally looking forward to get it and see if I will finally change my mind. May be I expect too much from HP but if we could have a decent RPN I may finally use this very promising hardware.