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