AMBER Archive (2004)

Subject: AMBER: MAXRING Antechamber problem

From: Karl N. Kirschner (
Date: Tue Sep 21 2004 - 14:37:44 CDT

Hey Everyone,
  We have ran into a small problem with antechamber (AMBER8 release).
We are trying to load a pdb that has several rings in the structure (a
tiny nanotube). We run antechamber and the output tells us :

"The ring number exceeds MAXRING, increase MAXRING and recompile the
programs, exitCannot open file ANTECHAMBER_BOND_TYPE.AC"

  So, we went into define.h under the $AMBERHOME/src/antechamber and
modified the file to read:
# define MAXCHAR 512 /* hamilton mod from 256 */
# define MAXATOM 1024 /* hamilton mod from 256 */
# define MAXBOND 2048 /* hamilton mod from 512 */
# define MAXRING 4096 /* hamilton mod from 1000 */

  After we recompile the program, we get the same error message. We
know for a fact that we do not have more than 4096 rings, in fact we
only have 168 atoms. I looked over the patches and there didn't seem to
be any addressing this concern (bugfix.6 was the closest). If I cut the
structure down, antechamber will eventually run without any problems.
Any ideas?


Karl Nicholas Kirschner, Ph.D.
Assistant Professor of Chemistry
Hamilton College, NY 13223

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