<div dir="ltr">Hi gmx-users,<br>I am having small doubt on energy minimisation that is <br>I have started protein system, when I do EM its showing that <br><pre>Step size too small, or no change in energy.<br>Converged to machine precision,<br>
but not to the requested precision Fmax < 800<br><br>Double precision normally gives you higher accuracy.<br><br>writing lowest energy coordinates,<br><br>Steepest Descents converged to machine precision in 45 steps,<br>
but did not reach the requested Fmax < 800.<br>potential Energy = -1.8373166e+06<br>Maximum force = 1.5158329e+04 on atom 519<br>Norm of force = 3.1759754e+04<br><br>After this I have reduced my system box size from 7nm to 6.8 cubic box its showed that "steepest descent converge Fmax<800 in 200 steps". This is fine.<br>
<br>In second case <br>I ran minimisation it showed that<br>"steepest descents didn't converge Fmax < 800" <br>when I use this output file as input of grompp, for run one more minimisation it showed "steepest descents converge Fmax < 800".<br>
</pre>here I have doubt that why in tha above mentioned two cases first time didn't converge the minimisation when I do modification like either reducing box size or doing one more minimization by using the output file of earlier minimisation then its converging.<br>
Can you give me brief idea why its happening<br><br>Thanks in advance<br></div>