Archive from user: Chris Neale The problem (which exists in 4.5.4), and a patch, are located here http://www.mail-archive.com/gmx-users@gromacs.org/msg41543.html I haven’t checked 4.6, but there is no mention of a fix to g\_order in the 4.6 release notes: http://www.gromacs.org/About\_Gromacs/Release\_Notes/Versions\_4.6.x Please note that this patch does not fix g\_order for all options, but should be useful for anybody who wants to fully implement the fix. I realize that it is most desirable that I upload a fully fixed version of g\_order, but I don’t have time at the moment. I have therefore opened this issue so that at least it doesn’t get forgotten about. A quick fix would be to have the current code throw an error when encountering unsaturated carbons, since these values are wrong (though widely reported in the literature based on g\_order). *(from redmine: issue id 1166, created on 2013-02-27 by gmxdefault)* * Uploads: * [g_order.patch](/uploads/25d3d803ae01fd83b44254a68d38f262/g_order.patch) The patch listed in the mailing list post * [gmx_order_4.5.4_modifiedbyChrisNeale.c](/uploads/17479cea65b965ac7df5eddf66a18f6f/gmx_order_4.5.4_modifiedbyChrisNeale.c)