(28/48/50) Lambert W Function

[Gil]

John,
Great your LambertW implementation!
Comparing your results with my proper HP50G program, I think that for special cases like:

k=-1 & input x tiny like {x=-1E-496 or x=-1E-497 or x=-1E-497 or x=-1E-499 }

or k=0 and x=1E-499

your program cannot give a correct answer.

Almost a pity.

Regards,
Gil