<p>Hey Widya,</p>
<p>In general, no, 15*2ns is not equal to 1*30ns. The reason for this lies in correlation and relaxation times. 15 simulations of 2ns give good statistics on relaxation and, if the system is equilibrated already, on short-term processes. A single simulation of 30 ns may relax to equilibrium, where a too short simulation does not and may show long term processes that extend 2ns. Yet a single simulation is only a single observation, such that the statistics are rather poor.</p>
<p>Hope it helps,</p>
<p>Tsjerk</p>
<p><blockquote type="cite">On Jul 25, 2011 4:56 PM, "Widya Desmarani" <<a href="mailto:widya.desmarani@gmail.com">widya.desmarani@gmail.com</a>> wrote:<br><br><div dir="ltr">Dear gromacs user,<br><br>I have been trying to look for an answer for my following question from our forum but still couldn't manage to find one. Probably it is trivial but I am not sure. <br>
<br>Instead of running a single relatively long simulation (say for about 30 ns), is it acceptable if we simulate multiple short simulations (say 15 simulations where each of them is 2 ns), and then, all the resulted trajectories are merged/concatenated into one single trajectory with the amount of total simulation 30 ns? I am interested in investigating bulk properties of liquid, such as compressibility, diffusion, and dielectric. <br>
<br>Many thanks.<br><br>Regards,<br>Widya<br></div>
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