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    On 3/12/2011 4:42 PM, pragna lakshmi wrote:
    <blockquote
cite="mid:CAD6uh5vEe9YUirXuXpCPkzoXo0dgU=G2YZs_KwS5OZ5sDDs0_g@mail.gmail.com"
      type="cite">Thank u for reply. I did energy minimization and
      equilibration step. It converged in 696 steps which is shown
      below.
      <div><br>
        <div>
          <div>Step= &nbsp;692, Dmax= 9.2e-03 nm, Epot= -7.12587e+05 Fmax=
            7.62150e+03, atom= 2099</div>
          <div>
            Step= &nbsp;693, Dmax= 1.1e-02 nm, Epot= -7.12588e+05 Fmax=
            9.72038e+03, atom= 2099</div>
          <div>Step= &nbsp;695, Dmax= 6.6e-03 nm, Epot= -7.12670e+05 Fmax=
            9.39830e+02, atom= 2099</div>
          <div><br>
          </div>
          <div>writing lowest energy coordinates.</div>
          <div><br>
          </div>
          <div>Steepest Descents converged to Fmax &lt; 1000 in 696
            steps</div>
          <div>Potential Energy &nbsp;= -7.1266969e+05</div>
          <div>Maximum force &nbsp; &nbsp; = &nbsp;9.3982965e+02 on atom 2099</div>
          <div>Norm of force &nbsp; &nbsp; = &nbsp;2.1967674e+01</div>
          <div><br>
          </div>
        </div>
      </div>
    </blockquote>
    <br>
    The atom that has the greatest force after EM is the same one for
    which LINCS warnings arise later. That's worth paying attention to.
    Read the advice about diagnosing unstable systems on the link Justin
    gave you last time.<br>
    <br>
    <blockquote
cite="mid:CAD6uh5vEe9YUirXuXpCPkzoXo0dgU=G2YZs_KwS5OZ5sDDs0_g@mail.gmail.com"
      type="cite">
      <div>
        <div>
          <div><br>
          </div>
          <div># md.mdp file</div>
          <div><br>
          </div>
          <div>
            <div>title = protein</div>
            <div>cpp = /lib/cpp ; location of cpp on SGI</div>
            <div>constraints = all-bonds</div>
            <div>integrator = md</div>
            <div>dt = 0.002 ; ps !</div>
            <div>nsteps = 1000000 ; total 50 ps.</div>
            <div>nstcomm = 1</div>
            <div>nstxout = 500 ; output coordinates every 1.0 ps</div>
            <div>nstvout = 0</div>
            <div>nstfout = 0</div>
            <div>nstlist = 10</div>
            <div>ns_type = grid</div>
            <div>rlist = 0.9</div>
            <div>coulombtype = PME</div>
            <div>rcoulomb = 0.9</div>
            <div>rvdw = 1.0</div>
            <div>fourierspacing = 0.12</div>
            <div>fourier_nx = 0</div>
            <div>fourier_ny = 0</div>
            <div>fourier_nz = 0</div>
            <div>pme_order = 6</div>
            <div>ewald_rtol = 1e-5</div>
            <div>optimize_fft = yes</div>
            <div>; Berendsen temperature coupling is on in four groups</div>
            <div>Tcoupl = berendsen</div>
            <div>tau_t = 0.1 0.1 0.1 0.1 0.1</div>
            <div>tc-grps = protein ZN IMP sol NA+</div>
            <div>ref_t = 300 300 300 300 300</div>
          </div>
        </div>
      </div>
    </blockquote>
    <br>
    <a class="moz-txt-link-freetext" href="http://www.gromacs.org/Documentation/Terminology/Thermostats">http://www.gromacs.org/Documentation/Terminology/Thermostats</a><br>
    <br>
    <blockquote
cite="mid:CAD6uh5vEe9YUirXuXpCPkzoXo0dgU=G2YZs_KwS5OZ5sDDs0_g@mail.gmail.com"
      type="cite">
      <div>
        <div>
          <div>
            <div>; Pressure coupling is on</div>
            <div>Pcoupl = berendsen</div>
            <div>pcoupltype = isotropic</div>
            <div>tau_p = 0.5</div>
            <div>compressibility = 4.5e-5</div>
            <div>ref_p = 1.0</div>
            <div>; Generate velocites is on at 300 K.</div>
            <div>gen_vel = yes</div>
            <div>gen_temp = 300.0</div>
            <div>gen_seed = 173529</div>
          </div>
        </div>
      </div>
    </blockquote>
    <br>
    It's probably not useful to re-generate velocities after the
    position-restrained step.<br>
    <br>
    Mark<br>
    <br>
    <blockquote
cite="mid:CAD6uh5vEe9YUirXuXpCPkzoXo0dgU=G2YZs_KwS5OZ5sDDs0_g@mail.gmail.com"
      type="cite">
      <div>
        <div>
          <div><br>
          </div>
          <div># pr.mdp file</div>
          <div><br>
          </div>
          <div>
            <div>title = protein</div>
            <div>cpp = /lib/cpp ; location of cpp on SGI</div>
            <div>
              define = -DPOSRES</div>
            <div>constraints = all-bonds</div>
            <div>integrator = md</div>
            <div>dt = 0.002 ; ps !</div>
            <div>nsteps = 50000 ; total 20.0 ps.</div>
            <div>nstcomm = 1</div>
            <div>nstxout = 250 ; output coordinates every 0.5 ps</div>
            <div>nstvout = 1000 ; output velocities every 2.0 ps</div>
            <div>nstfout = 0</div>
            <div>nstlog = 10</div>
            <div>nstenergy = 10</div>
            <div>nstlist = 10</div>
            <div>ns_type = grid</div>
            <div>rlist = 0.9</div>
            <div>coulombtype = PME</div>
            <div>rcoulomb = 0.9</div>
            <div>rvdw = 1.0</div>
            <div>fourierspacing = 0.12</div>
            <div>fourier_nx = 0</div>
            <div>fourier_ny = 0</div>
            <div>fourier_nz = 0</div>
            <div>pme_order = 6</div>
            <div>ewald_rtol = 1e-5</div>
            <div>optimize_fft = yes</div>
            <div>; Berendsen temperature coupling is on in four groups</div>
            <div>Tcoupl = V-rescale</div>
            <div>tau_t = 0.1 0.1 0.1 0.1 0.1</div>
            <div>tc_grps = protein ZN sol IMP NA+</div>
            <div>ref_t = 300 300 300 300 300</div>
            <div>; Pressure coupling is on</div>
            <div>Pcoupl = no</div>
            <div>pcoupltype = isotropic</div>
            <div>tau_p = 0.5</div>
            <div>compressibility = 4.5e-5</div>
            <div>ref_p = 1.0</div>
            <div>; Generate velocites is on at 300 K.</div>
            <div>gen_vel = yes</div>
            <div>gen_temp = 300.0</div>
            <div>gen_seed = 173529</div>
          </div>
          <div><br>
          </div>
          <div>#em.mdp file</div>
          <div><br>
          </div>
          <div>
            <div>title = protein</div>
            <div>cpp = /lib/cpp ; location of cpp on SGI</div>
            <div>define = -DFLEX_SPC ; Use Ferguson&#8217;s Flexible water
              model [4]</div>
            <div>constraints = none</div>
            <div>integrator = steep</div>
            <div>dt = 0.002 ; ps !</div>
            <div>nsteps = 2000</div>
            <div>nstlist = 10</div>
            <div>ns_type = grid</div>
            <div>rlist = 0.9</div>
            <div>coulombtype = PME ; Use particle-mesh ewald</div>
            <div>rcoulomb = 0.9</div>
            <div>rvdw = 1.0</div>
            <div>fourierspacing = 0.12</div>
            <div>fourier_nx = 0</div>
            <div>fourier_ny = 0</div>
            <div>fourier_nz = 0</div>
            <div>pme_order = 4</div>
            <div>ewald_rtol = 1e-5</div>
            <div>optimize_fft = yes</div>
            <div>;</div>
            <div>; Energy minimizing stuff</div>
            <div>;</div>
            <div>emtol = 1000.0</div>
            <div>emstep = 0.01</div>
          </div>
          <div><br>
          </div>
          <div>I need further help to trouble shoot this problem.</div>
          <div><br>
          </div>
          <div><br>
          </div>
          <div><br>
          </div>
          <div><br>
            <div class="gmail_quote">On Sat, Dec 3, 2011 at 10:46 AM,
              Justin A. Lemkul <span dir="ltr">&lt;<a
                  moz-do-not-send="true" href="mailto:jalemkul@vt.edu">jalemkul@vt.edu</a>&gt;</span>
              wrote:<br>
              <blockquote class="gmail_quote" style="margin:0 0 0
                .8ex;border-left:1px #ccc solid;padding-left:1ex;">
                <div class="im"><br>
                  <br>
                  pragna lakshmi wrote:<br>
                  <blockquote class="gmail_quote" style="margin:0 0 0
                    .8ex;border-left:1px #ccc solid;padding-left:1ex">
                    Hi,<br>
                    &nbsp; &nbsp; I am trying to run protein-ligand complex
                    simulation. At the final MD run step it is showing
                    the following error. Can anybody tell me the
                    solution for this error?<br>
                    <br>
                  </blockquote>
                  <br>
                </div>
                <a moz-do-not-send="true"
href="http://www.gromacs.org/Documentation/Errors#LINCS.2fSETTLE.2fSHAKE_warnings"
                  target="_blank">http://www.gromacs.org/Documentation/Errors#LINCS.2fSETTLE.2fSHAKE_warnings</a><br>
                <br>
                There are hundreds of threads in the archive with the
                same issue and several possible solutions. &nbsp;Please
                consult the link above (and referenced pages), as well
                as other posts.<br>
                <br>
                If you need further help diagnosing the problem, please
                post a complete .mdp file, as well as a description of
                prior minimization and equilibration.<br>
                <br>
                -Justin<br>
                <br>
                -- <br>
                ========================================<br>
                <br>
                Justin A. Lemkul<br>
                Ph.D. Candidate<br>
                ICTAS Doctoral Scholar<br>
                MILES-IGERT Trainee<br>
                Department of Biochemistry<br>
                Virginia Tech<br>
                Blacksburg, VA<br>
                jalemkul[at]<a moz-do-not-send="true"
                  href="http://vt.edu" target="_blank">vt.edu</a> |
                (540) 231-9080<br>
                <a moz-do-not-send="true"
                  href="http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin"
                  target="_blank">http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin</a><br>
                <br>
                ========================================<span
                  class="HOEnZb"><font color="#888888"><br>
                    -- <br>
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                  </font></span></blockquote>
            </div>
            <br>
            <br clear="all">
            <div><br>
            </div>
            -- <br>
            <div style="line-height:normal"><span
                style="font-family:&quot;Times New
                Roman&quot;,&quot;serif&quot;;font-size:12pt">T.Pragna
                Lakshmi,</span></div>
            <div style="line-height:normal"><span
                style="font-family:&quot;Times New
                Roman&quot;,&quot;serif&quot;;font-size:12pt">Junior
                Scientist,</span></div>
            <div style="line-height:normal"><span
                style="font-family:&quot;Times New
                Roman&quot;,&quot;serif&quot;;font-size:12pt"><span
                  style="font-family:&quot;Times New
                  Roman&quot;,&quot;serif&quot;;font-size:12pt">Vision
                  Research Center,</span></span></div>
            <div style="line-height:normal"><span
                style="font-family:&quot;Times New
                Roman&quot;,&quot;serif&quot;;font-size:12pt">Sankara
                Netralaya,</span></div>
            <div style="line-height:normal"><span
                style="font-family:&quot;Times New
                Roman&quot;,&quot;serif&quot;;font-size:12pt">Chennai,</span></div>
            <div style="line-height:normal"><span
                style="font-family:&quot;Times New
                Roman&quot;,&quot;serif&quot;;font-size:12pt">India.</span></div>
            <div style="line-height:normal"><span
                style="font-family:&quot;Times New
                Roman&quot;,&quot;serif&quot;;font-size:12pt">Pin:
                600006.</span></div>
            <br>
          </div>
        </div>
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    </blockquote>
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