On Wed, Mar 24, 2010 at 12:25:01PM +0100, Miguel Martinez Canales wrote: > Dear all, > > Following Paolo's warning, I've performed some tests with a not so > surprising result: Paolo was right. For some reason, the ubuntu 9.10 > builds of gfortran 4.3 and 4.4.1 give astonishingly different results > for example07. Well, the pw.x output is the same as in the reference, > but the lambda values... at least they are of the same order of > magnitude. Mind you, for once this is not an ubuntu bug, as it also > happens in self-compiled gfortran 4.4.3 (Red Hat 5.4 in this case). > However, the differences in lambda don't seem important in the case of > gfortran 4.1.2 (the default in Red Hat) or 4.2.4 (the oldest version > available in ubuntu 9.10). > > I'm going to check other examples to see whether there are very > different phonon frequencies elsewhere, but I don't expect anything > good at all.
I am in contact with one of the gfortran developers, and reported the problem with ph.x to him; he now spent quite some time tracing the problem down, and apparently there is a patch on-queue: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43551#c10 -- c u henning
