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Hi,<br><br>That will depend on what kind of properties you are looking at and how accurate you want them.<br>Have inaccurate constraining will usually lead to energy leaking out of your system.<br>If you use reaction-field this will add energy into the system, probably even more than<br>the constraints leak, so in that sense the error is probably not significant.<br><br>Have a look at your temperature, the constraint inaccuracy should cause a lowering<br>of the temperature, the steady temperature value will also be affected by your coupling time.<br><br>Berk<br><br>> Date: Mon, 16 Mar 2009 15:55:05 +0100<br>> From: andreas.frank@ch.tum.de<br>> To: gmx-users@gromacs.org; Oliver.Demmer@ch.tum.de<br>> CC: <br>> Subject: [gmx-users] Wrong Shake Tolerance<br>> <br>> Dear Gromacs-Users,<br>> <br>> we have the following problem: after running several hundred nanoseconds <br>> of a peptide (Gromos FF 53a6) in spc-water (NpT ensemble), we recognized <br>> that the tolerance of shake (all-bonds were constrained) was wrongly <br>> adjusted: instead of calculating with shake_tol = 0.0001, the value was <br>> 0.01. Our question is now if the additional noise we produced in this <br>> way makes a repetition of the runs necessary or not? Density, pressure, <br>> etc. of the boxes are ok, but we are not sure what kind of artifacts <br>> could have arisen due to this wrong setup. The integration time step was <br>> 2 fs.<br>> Thanks for your help and suggestions!<br>> <br>> Cheers,<br>> <br>> Andreas<br>> _______________________________________________<br>> gmx-users mailing list gmx-users@gromacs.org<br>> http://www.gromacs.org/mailman/listinfo/gmx-users<br>> Please search the archive at http://www.gromacs.org/search before posting!<br>> Please don't post (un)subscribe requests to the list. Use the <br>> www interface or send it to gmx-users-request@gromacs.org.<br>> Can't post? Read http://www.gromacs.org/mailing_lists/users.php<br><br /><hr />Express yourself instantly with MSN Messenger! <a href='http://clk.atdmt.com/AVE/go/onm00200471ave/direct/01/' target='_new'>MSN Messenger</a></body>
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