Path: utzoo!attcan!uunet!yale!cmcl2!lanl!jlg From: jlg@lanl.gov (Jim Giles) Newsgroups: comp.lang.fortran Subject: Re: intrinsic functions, math operators (was: i++, i+=1, i=i+1) Message-ID: <4093@lanl.gov> Date: 23 Sep 88 21:23:05 GMT References: <596@convex.UUCP> Organization: Los Alamos National Laboratory Lines: 16 From article <596@convex.UUCP>, by dodson@mozart.uucp (Dave Dodson): > [...] > Considering the complexity and length of a properly written pow() > routine, it does not appear to me to be practical for the compiler to > in-line it. [...] pow(x,3) == x*x*x appears to me to be both accurate and short enough to be expanded in-line. The same goes for pow(x,-4.) == 1/((x*x)*(x*x). _Most_ uses of the exponentiation operator in Fortran are of this kind. Therefore, _most_ uses would benefit from in-line optimization. Things like pow(x,3.14159) could still call an external to solve - that's the power of letting the compiler in on the semantics of the basic operations. J. Giles Los Alamos