Re: [Towhee-users] maxextrema exceeded
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From: Greg L. <gs...@ps...> - 2009-05-13 17:06:03
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I am replying to my own email for 2 reasons: 1) to share my solution with others who may have similar problems, and 2) to check with more experienced users that this solution is valid. In reading through other emails in the archive, the idea of using an alternate force field style for the torsions dawned on me. Initially, modifying the custom towhee_ff file created during the LAMMPS import process, I changed the torsion style from 3 (AMBER) to 21 (Multiple Rigid Dihedrals) (and made the appropriate changes throughout the rest of towhee_ff) got rid of the error "ATD_CBMC_SETUP:maxextrema exceeded" but introduced a new error "overlap in initial structure". I presume this is because many of the dihedral angles were not at their precise equilibrium positions. As seen in the benzene2_ff from another email in the archive, I tried using the torsion style of 8 (nonbonded terms only) with One-Four Nonbond Logical set to false. This sets the torsional energy within the large complex molecule to 0, thereby avoiding the "overlap in initial structure". I think this will work because I am not performing any MC moves that involve changing the molecule conformation, only in simulating the adsorption of simple gasses onto this structure. Thanks, -Greg On Wed, May 13, 2009 at 10:11 AM, Greg Larsen <gs...@ps...> wrote: > Hello, > I am attempting to import a complex structure (many fused aromatic rings) > from LAMMPS into Towhee. While most of the importing process seems to be > working great, I get the following error: > > Verifying input structures are consistent > Determining Autofit Gaussian bond parameters > Determining Autofit Gaussian bend A parameters > Determining Autofit Gaussian bend B parameters > Determining Autofit Gaussian dihedral parameters > ATD_CBMC_SETUP:maxextrema exceeded > > Any suggestions on how to overcome this? > > maxextrema is defined in atd_cbmc_setup.F as: maxextrema = > 2*(CBMC_MAXTORPEAKS+CBMC_MAXBENDPEAKS). I tried doubling the values of > CBMC_MAXTORPEAKS and CBMC_MAXBENDPEAKS in preproc.h (and then recompiling), > but get the same error. > > I am guessing this problem is due to difficulties in using CBMC methods on > a complex structure. If it helps, I do not need to use CBMC methods on this > structure, I am only intersted in using Towhee to model adsorption onto this > structure. > > Thanks, > > -Greg Larsen > |