[gmx-users] Hessian Calculation
jair at iq.ufrj.br
Fri Dec 9 18:57:58 CET 2005
I'm tryng to do a normal mode analysis with gromacs
I performed the minimization of a protein structure in vacuo using the l-bfgs
After the minimizaton the results were:
Low-Memory BFGS Minimizer converged to machine precision in 24550 steps,
but did not reach the requested Fmax < 1e-08.
Potential Energy = -4.09184275152338e+03
Maximum force = 1.66412131872925e-07 on atom 855
Norm of force = 8.31243056797603e-09
Then I prepared an .mdp file with just one line
integrator = nm
grompp_d -f hess.mdp -c lbfgs15.g96 -p prot.top -o hess.tpr -t lbfgs15.trr -e
mdrun_d -v -s hess.tpr -o -c hess.g96 -e hess.edr -g hess.log -mtx hess.mtx
A message of the program appears saying:
Maximum force: 1.36197e+03
Maximum force probably not small enough to ensure that you are in a
energy well. Be aware that negative eigenvalues may occur when the
resulting matrix is diagonalized.
Ins't the maximum force 1.66412131872925e-07 as show above ?
Am I doing something wrong?
More information about the gromacs.org_gmx-users