-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
Hi Haydyn-- > Hi guys, I've been using XPLOR-NIH for a while now but until recently > had not come across the following error: > > --> ERROR: matrix is not a rotation matrix. Is this by chance using the original XPLOR torsion angle dynamics code (DYNAmics TORSion)?? You probably should switch over to using DYNAmics INTErnal instead. See eginput/protG/anneal.inp for an example of this. > > This seems to happen when I use a torsion angle dynamics protocol, but > change my noe potential from: > > potential all soft > > to: > > potential all square > > > The protocol I'm using for simulated annealing works perfectly when I > use the "soft" noe potential function, and dies with the aforementioned > error if this is changed to "square". I've tried to isolate the > problem, but all I can conclude at this stage is that "soft" lets things > work, and "square" doesn't. Can anyone give me the low-down on what > silly mistake I have probably made? I did find something about ARIA/CNS > giving this error when using a torsion angle dynamics protocol, and that > it can be a timestep issue. I feel quite happy with a 0.015 ps > timestep and find that reducing it to less desirable values fails to > fix the problem. If its a timestep issue, it's not too surprising that a softer potential is more successful. The above mentioned internal dynamics routine has a variable timestep facility which should be able to dance around bad steps. [In addition, the code executes about three times faster.] Please let me know if you need any further assistance with this. Charles -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) Comment: Processed by Mailcrypt 3.5.8 <http://mailcrypt.sourceforge.net/> iD8DBQE/DW2HPK2zrJwS/lYRAueZAJ0YajWA/Q1Cdz66UJdzmXjcfa04PQCeNywU uYwKDz6RkHS6Fbtm6Fhf8NY= =EQj4 -----END PGP SIGNATURE-----
