From: lindahl@cs.virginia.edu (Greg Lindahl) Newsgroups: comp.parallel.mpi Subject: Re: Environment variables under MPI()? Date: 22 Aug 1998 03:19:06 GMT Organization: a guest of Shadow Island Games Message-Id: <6rldba$mlf@news1.newsguy.com> References: <35DE20E3.2781@dao.gsfc.nasa.gov> Jing Guo writes: > > Sure: write your own small piece of code to pass these variables > > around at the start of your run. > > It is the most frequent suggestion I heard before, but I didn't like it: > > a) It won't work if the implementation does not even have the > _right_ values for the root processor. (Yes, such implementation > does exist.) I assume you were also talking about values defined > _externally_, not _internally_ by a program. It is easy to write a program to write the Unix environment into a file, and then have your MPI root program read this file and send its contents to all the other nodes. > b) It might not be portable. Since it is really an OS interface > issue, it should not be determined unilaterary by a software > developer. It's a lot more portable than complaining that MPI implementations should propagate the Unix environment! > c) Thinking you are given a communicator and expected to develop a > library working in that given world, I wonder my own small piece > of code will ever work under that situation. It is not a surprise that a library should need initialization in order to run. It _is_ a surprise that you think the Unix environment is the right place to put it. Given that the MPI standard doesn't even really address access to conventional Fortran files, I think you are expecting too much of the standard. -- g