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<p>Dear GMX'ers!</p>
<p><br></p>
<p>I simulate system of about hundreds of water molecules in NVE ensemble with md integrator. Every 100 ps I need to change slightly some parameters, say, electric field and to continue the simulation from this point. As I realize I cannot go on my run using the checkpointing and tpbconv in this case. Therefore I try to use the output structure file confout.gro which contains both coordinates and velocities at the end of the previous step. </p>
<p><br></p>
<p>The problem is in the total energy. Within every 100-ps run the energy drift is quite low. But when I start the next step, at its very beginning I see the considerable jump in the total energy and the temperature comparing with the end values of previuos step. </p>
<p>NOTE that it is the case even when I change NOTHING in my job.mdp file! </p>
<p><br></p>
<p>To my knowledge the coordinates and velocities define exactly the energy and the temperature. Now I suspect the only reason - low precision of confout.gro. So, my questions are:</p>
<p>Is there another reason for the total energy non-conservation in my simulation?</p>
<p>How can I get the full precision in output structure file RIGTH after mdrun? Or it is mandatory to use trjconv with -ndec option?</p>
<p>What is the default precision of .trr trajectory file in single and double precision modes?</p>
<p><br></p>
<p>Hoping for your help,</p>
<p><span class=rvts6>-- </span></p>
<p><span class=rvts6>Regards,</span></p>
<p><span class=rvts6> Dmitri </span><a class=rvts7 href="mailto:ddubov@ngs.ru">mailto:ddubov@ngs.ru</a></p>
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