Xref: utzoo comp.lang.fortran:1524 comp.lang.misc:2180 Path: utzoo!attcan!uunet!husc6!mailrus!uflorida!ufqtp!bernhold From: bernhold@qtp.ufl.edu (David E. Bernholdt) Newsgroups: comp.lang.fortran,comp.lang.misc Subject: Re: Branch frequencies (was Assembly or ....) Message-ID: <391@red17.qtp.ufl.edu> Date: 28 Nov 88 14:42:52 GMT References: <4113@enea.se> Reply-To: bernhold@red17 (David E. Bernholdt) Organization: University of Florida Quantum Theory Project Lines: 29 In article <4113@enea.se> sommar@enea.se (Erland Sommarskog) writes: >If memory serves right the compiler Rubin wants exists, or >at least it has existed. I recall a friend of mine told me >that the very first Fortran compiler allowed you to give >probabilities of on the IF statements. The compiler then used >one of its passes to do a Monte Carlo simulation on the >program for optimal optimising. > >"Frequently, unexpected errors are entirely unpredictable" - Digital Equipment I too may be mistaken, but I believe that the compiler for the Multiflow does things like this too: in order to schedule the "traces" most efficiently, it will analyze the branch condition and try to determine probabilities. Furthermore, I believe you can automatically instrument the executable during compilation and run a few jobs with it - then feed the collected data back to the compiler to help it optimize more efficiently. Warning: I don't really know much about the machine, I just listened to a Multiflow rep making his pitch to a large group of computation chemists who ask good questions. Sounds interesting nevertheless! Dave -- David Bernholdt bernhold@qtp.ufl.edu Quantum Theory Project bernhold@ufpine.bitnet University of Florida Gainesville, FL 32611 904/392 9306