http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53549
--- Comment #3 from Conrad <conradsand.arma at gmail dot com> 2012-06-01 13:27:47 UTC --- arma::ivec3 from Armadillo works under gcc 4.4.6 20110731 (Red Hat 4.4.6-3). This bug might be related to 52470 and 52685: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52470 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52685 However, Christoffer mentioned that arma::ivec3 doesn't work with gcc-snapshot 4.8.20120520, while bug 52685 seems to be resolved as of 2012-03-29.
