Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!weyrich!orville From: orville@weyrich.UUCP (Orville R. Weyrich) Newsgroups: comp.lang.fortran Subject: Re: NAG Fortran 90 announcement Message-ID: <1991Jun26.172618.364@weyrich.UUCP> Date: 26 Jun 91 17:26:18 GMT References: <15634@exodus.Eng.Sun.COM> <26334@lanl.gov> Reply-To: orville@weyrich.UUCP (Orville R. Weyrich) Organization: Weyrich Computer Consulting Lines: 41 In article przemek@rrdstrad.nist.gov (Przemek Klosowski) writes: > >>>>>> On 24 Jun 91 16:31:36 GMT, jlg@cochiti.lanl.gov (Jim Giles) said: > >Jim> The thing that's most disappointing about NAG's implementation is that >Jim> it's a preprocessor to C. (They claim that it's a compiler because it >Jim> does "global" (throughout a whole program unit) analysis, but it still >Jim> outputs C as it's "object" code.) This means that those users who are >Jim> the most anxious to try out the 'whole array' notation will get an very >Jim> unsatisfactory comparison because of the pessimizing effect of C on >Jim> array (in C: pointers) calculations. > I would say that if the NAG f90 is truly standard conforming, then it is a great product, regardless of the efficiency of its output. I would greatly prefer having a standard implementation available to compare my results to while I was writing my own whiz-bang hot optimizing f90 compiler. So how about moving this discussion in the direction of how accurately the NAG implementation adheres to the standard? > In the case of my friend's code, a lot of time was spent in >calculating distances between particles. Many of these calculations >were unnecessary because the particles were far apart. If I were >writing in C, I would venture to create linked lists of particle >clusters, "topologically" limiting the interactions to clusters of particles >that are known to lie close to each other (a la Jon Bentley). I do not >know of a good way of expressing such things in Fortran (flameproof suit on) Uh, they were talking at one time about adding pointers to Fortran-9x. Did that get cut during the revision process? -------------------------------------- ****************************** Orville R. Weyrich, Jr., Ph.D. Certified Systems Professional Internet: orville%weyrich@uunet.uu.net Weyrich Computer Consulting Voice: (602) 391-0821 POB 5782, Scottsdale, AZ 85261 Fax: (602) 391-0023 (Yes! I'm available) -------------------------------------- ******************************