DEXP or EXP for exponential function in fortran?

Question

I have two very short questions:

1 - I just read that DEXP() is the archaic form of EXP(). Does it mean that it should not be used an

Answer 1

The answer to part 2 of your question is that the range of the exponential function is the set of all positive real numbers. In Fortran terms that means the set of all REAL numbers greater than 0. Yes it is, according to the Fortran standards, compiler dependent, but in practice you won't go far wrong if you take it to be the set of all positive IEEE floating-point numbers, single or double precision as you wish. But to be strict you need to be familiar with the KINDs of real numbers that your compiler supports which will almost certainly include the IEEE f-p numbers, but may include others too.