Path: utzoo!attcan!uunet!lll-winken!lll-lcc!well!rchrd From: rchrd@well.UUCP (Richard Friedman) Newsgroups: comp.lang.fortran Subject: Re: Fastest Fortran Engine? Message-ID: <6386@well.UUCP> Date: 27 Jun 88 18:41:19 GMT References: <5377@cup.portal.com> <2852@mmintl.UUCP> <1005@cresswell.quintus.UUCP> <701@garth.UUCP> <2157@sugar.UUCP> <777@garth.UUCP> <10757@ames.arc.nasa.gov> <7568@boring.cwi.nl> <10889@ames.arc.nasa.gov> Reply-To: rchrd@well.UUCP (Richard Friedman) Organization: RCHRD 2855 Telegraph #415 Berkeley CA 94705 Lines: 21 One reason why the NEC SX-2 does so well on matrix operations is that their compiler is one of the best!. See "Vectorizing Compilers: A Test Suite and Results" from Argonne (Tech Memo #109, March 31, 1988) from Dongarra, Callahan and Levine. It gives the results of running a large (100+) suite of routines thru a number of vectorizing compilers. Altho execution times are not given, (that WOULD be interesting!), they were only rating these compilers on their ability to vectorize/optimize source code. On a composite scale, the NEC compiler vectorize 59 out of 100 loops while CFT 1.15 did 51% and CFT77 did 52%. I should mention that the Alliant compiler did 71% and so did the Amdahl FORTRAN 77/VP. The FTN77 compiler on the ETA-10 did 69%. The point is that the NEC SX-2 runs faster than the X-MP in vector mode (clock is 6ns) so the more code you get into vector mode the better you are. I suppose that more loops in the LINPACK test were vectorized by the NEC compiler than the Cray. But thats just a guess. The SX-2 is a significant machine. -- ...Richard Friedman [rchrd] uucp: {ucbvax,lll-lcc,ptsfa,hplabs}!well!rchrd - or - rchrd@well.uucp