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On 21/09/2011 1:38 AM, Andrey Dyachenko wrote:
<blockquote
cite="mid:CAEsXS9AO40ZgYYgfYZQ+u+w_peSUvD77iNYFoimKfS9cYa359g@mail.gmail.com"
type="cite">Dear gmx-users,
<div><br>
</div>
<div>I am trying to perform the Normal Mode Analysis of 24 kDa
protein in water. Here is the .mdp file I am using:</div>
<div><br>
</div>
<div>
<div>integrator = nm</div>
<div>dt = 0.002 </div>
<div>nsteps = 10000 </div>
<div>emtol = 1 </div>
<div>nstcomm = 1 </div>
<div>nstxout = 0 </div>
<div>nstxtcout = 1000</div>
<div>nstvout = 0 </div>
<div>nstlog = 5000 </div>
<div>nstenergy = 20 </div>
<div>nstlist = 6 </div>
<div>ns_type = grid </div>
<div>coulombtype = cut-off</div>
<div>epsilon_r = 80.0</div>
<div>rcoulomb = 1.4</div>
<div>fourierspacing = 0.12</div>
<div>pmeorder = 4</div>
<div>optimize_fft = yes</div>
<div>ewald_rtol = 1.0e-5</div>
<div>DispCorr = EnerPres</div>
<div>constraints = none</div>
<div>rlist = 0.9 </div>
<div>rvdw = 0.9 </div>
<div>Tcoupl = berendsen </div>
<div>ref_t<span class="Apple-tab-span" style="white-space:pre">
</span> = 330 </div>
<div>tc-grps = protein<span class="Apple-tab-span"
style="white-space:pre"> </span></div>
<div>tau_t<span class="Apple-tab-span" style="white-space:pre">
</span> = 0.5 </div>
<div>Pcoupl = no <span
class="Apple-tab-span" style="white-space:pre"> </span></div>
<div>Pcoupltype = isotropic </div>
<div>tau_p = 1.0 </div>
<div>compressibility = 4.5e-5</div>
<div>ref_p = 1.0</div>
<div>gen_vel = no </div>
<div>gen_temp = 300 </div>
<div>gen_seed = 1993 </div>
</div>
<div><br>
</div>
<div><br>
</div>
<div>And I get the error message: </div>
<div><br>
</div>
<div>
<div>Fatal error:</div>
<div>Constraints present with Normal Mode Analysis, this
combination is not supported</div>
<div>For more information and tips for troubleshooting, please
check the GROMACS</div>
<div>website at <a moz-do-not-send="true"
href="http://www.gromacs.org/Documentation/Errors">http://www.gromacs.org/Documentation/Errors</a></div>
<div><br>
</div>
<div>despite the constraint = none line. </div>
<br>
</div>
</blockquote>
<br>
By default, the water models include constraints. Check out the .itp
file for your water, and you can use a define = -DWHATEVER in your
.mdp file to choose a flexible water model. Be sure you really want
(all of the) water present in this analysis.<br>
<br>
Mark<br>
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