To: mpi-21@XXXXXXXXXXXXX Subject: Re: IEEE Floating point In-reply-to: Your message of "Mon, 14 May 2001 15:52:09 EDT." Date: Tue, 15 May 2001 10:04:06 +0100 From: James Cownie Sender: owner-mpi-21@XXXXXXXXXXXXX Precedence: bulk Reply-To: mpi-21@XXXXXXXXXXXXX Marc Snir wrote :- > Another issue: I expect that most Fortran bindings of MPI are > layered atop a C binding. This implies that the floating point > operations done in the fortran MPI library may not be fully > compliant to the Fortran floating point spec (when and whether one > generates exceptions, how one handles NANs, the handling of > denormalized numbers, etc.). I is worthwhile to add a clarification > to that extent. While it is entirely possible that the numerics inside the library will not be the same as those which would occur were functionally equivalent code implemented in Fortran, this is not a standards issue. The Fortran standards say nothing about NaNs, exceptions or denorms, all of which are IEEE floating point arithmetic issues. Fortran standards certainly do not require that compliant Fortran systems use IEEE arithmetic. (And neither do any C standards). I don't really think that there's much to say here. Whenever you call a library from Fortran you (should) already expect that the exception behaviour and numerics will not be influenced by the way you compiled your code, and that's all that is happening here. -- Jim James Cownie Etnus, LLC. +44 117 9071438 http://www.etnus.com