Dear staff:<br />When I do the energy minimization of my system contain a protein, an ATP and water molecules using <span style="font-weight: bold; font-style: italic;">mdrun</span>, it stopped at 15 steps, and return this messege:<br style="font-style: italic;" /><span style="font-style: italic;">Steepest Descents:</span><br style="font-style: italic;" /><span style="font-style: italic;">   Tolerance (Fmax)   =  1.00000e+00</span><br style="font-style: italic;" /><span style="font-style: italic;">   Number of steps    =         2000</span><br style="font-style: italic;" /><span style="font-style: italic;">Step=    0, Dmax= 1.0e-02 nm, Epot= -3.24259e+05 Fmax= 3.22275e+04, atom= 1264</span><br style="font-style: italic;" /><span style="font-style: italic;">Step=   14, Dmax= 1.2e-06 nm, Epot=          nan Fmax= 2.96890e
+04, atom= 1262</span><br style="font-style: italic;" /><span style="font-style: italic;">Stepsize too small, or no change in energy.</span><br style="font-style: italic;" /><span style="font-style: italic;">Converged to machine precision,</span><br style="font-style: italic;" /><span style="font-style: italic;">but not to the requested precision Fmax < 1</span><br style="font-style: italic;" /><br style="font-style: italic;" /><span style="font-style: italic;">Double precision normally gives you higher accuracy.</span><br style="font-style: italic;" /><span style="font-style: italic;">You might need to increase your constraint accuracy, or turn</span><br style="font-style: italic;" /><span style="font-style: italic;">off constraints alltogether (set constraints = none in mdp file)</span><br style="font-style: italic;" /><br style="font-style: italic;" /><span style="font-style: italic;">writing lowest energy coordinates.</span><br style="font-style: italic;" /><br style=
"font-style: italic;" /><span style="font-style: italic;">Steepest Descents converged to machine precision in 15 steps,</span><br style="font-style: italic;" /><span style="font-style: italic;">but did not reach the requested Fmax < 1.</span><br style="font-style: italic;" /><span style="font-style: italic;">Potential Energy  = -3.2425944e+05</span><br style="font-style: italic;" /><span style="font-style: italic;">Maximum force     =  3.2227543e+04 on atom 1264</span><br style="font-style: italic;" /><span style="font-style: italic;">Norm of force     =            nan</span><br /><br /><br /><span style="font-weight: bold;">what's wrong with it? My .mdp file is:</span><br style="font-weight: bold;" /><span style="font-style: italic;"><br />integrator   =   steep ;minimization method</span><br style="font-style: italic;" /><span style="font-style: i
talic;">emtol   =   1.0   ; stop minimization when max force < 1.0 KJ/mol</span><br style="font-style: italic;" /><span style="font-style: italic;">nsteps   =   2000 ; max step number</span><br style="font-style: italic;" /><span style="font-style: italic;">nstenergy   =   10 ;n step to write energy</span><br style="font-style: italic;" /><span style="font-style: italic;">nstxtcout   =   10 ;n step to write coordinates file</span><br style="font-style: italic;" /><br style="font-style: italic;" /><span style="font-style: italic;">nstlist   =   1 ;the step to update the neighbour step list</span><br style="font-style: italic;" /><span style="font-style: italic;">ns_type   =   simple; the method to determine neighbour list</span><br style="font-style: italic;" /><span style="font-style: italic;">rlist   =   1.0 ;cutoff for mak
e neighbour list</span><br style="font-style: italic;" /><span style="font-style: italic;">coulombtype    =   cutoff ;cutoff for electrostatic force distance</span><br style="font-style: italic;" /><span style="font-style: italic;">rcoulomb   =   1.0 ;long range cutoff for elect.</span><br style="font-style: italic;" /><span style="font-style: italic;">rvdw   =   1.0 ; long range cutoff for vdw</span><br style="font-style: italic;" /><span style="font-style: italic;">constraints   =   none ;no constraint</span><br style="font-style: italic;" /><span style="font-style: italic;">pbc   =   no ; no periode boundary conditions</span><br /><br />Best wishes!<br style="font-style: italic;" />