Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!ukma!rutgers!rochester!uhura.cc.rochester.edu!ur-valhalla!davis From: davis@galaxy.ee.rochester.edu (Al Davis) Newsgroups: comp.lang.fortran Subject: Re: Fortran versus C for numerical anal Message-ID: <1483@valhalla.ee.rochester.edu> Date: 22 Sep 88 01:43:49 GMT References: <1475@valhalla.ee.rochester.edu> <3963@lanl.gov> Sender: usenet@valhalla.ee.rochester.edu Reply-To: davis@galaxy.ee.rochester.edu (Al Davis) Organization: UR Dept. of Electrical Engg, Rochester NY 14627 Lines: 32 I said... >> Here is a challenge: write a portable program that does LU decomposition of >> a matrix of arbitrary size, in Fortran. I believe it can't be done, in a >> straightforward way. (Read the input, do it, write the result) >> Someone please prove me wrong. In article <3963@lanl.gov> jlg@lanl.gov (Jim Giles) writes: >We have a Monte-Carlo particle code that uses dynamic memory. It is entirely >written in standard Fortran except for the two routines that actually >allocate and free the dynamic memory. Well, then it is not portable. >portability problems are limited to differences in file naming conventions >on the various systems and to numerical differences in the hardware. These >problems would effect porting a code written in _any_ language. They could, but they don't have to. In my example, use stdin and stdout. It is bad practice to hard code file names in any system. I didn't say anything about precision. The machine default is fine, so numerical differences are not an issue for such a simple problem. >Please note that the C dynamic memory routines _also_ can't be written >entirely in C. I don't care. malloc exists as a part of the library supplied with every C compiler, except for a few joke versions. Portable Fortran has no counterpart. You are allowed to use the standard library. Do you accept the challenge? I still don't think you can do it. Al Davis