RE: HP48-HP50G : Error functions ERF(z), FRESNEL integrals, PROBIT, etc.

[John Keith]

(11-11-2023 09:26 AM)Gil Wrote:  Question 1:
Is there an elegant way to solve for the introduced variable X without creating that new variable (that I can of course delete at the end of the programs iERF and iERFc by 'X' PURGE)?

Question 2:
How could I calculate erf(i*x) for x=0.5 in
'2/sqrt(pi)*S(0.,.5*i,e^-t^2.,t)' ?
A way should be to implement the explanations given in
https://math.stackexchange.com/questions...inary-part

Could you make x a local variable? I've never tried using local variables with ROOT but it should work.

The formula in the stackexchange link seems straightforward but the resulting program would be big and slow. Unfortunately, neither UTPC nor UTPN allow complex arguments. The vast majority of calculations using ERF involve small, positive real numbers. If I ever need to calculate complex ERF I will probably just use Mathematica or some such.