rajat desikan wrote:
Justin,
Should i turn off charges on the methane molecules? I have left them on.


What force field are you using? If you've got an all-atom model of methane, you should have partial charges.

-Justin

On Mon, Nov 21, 2011 at 12:32 AM, Justin A. Lemkul <jalem...@vt.edu <mailto:jalem...@vt.edu>> wrote:



    rajat desikan wrote:

        My simulations are for 10 ns in each window. There is a lot of
        noise in my wham too. I am enclosing my wham for pullf (the
        earlier was pullx) and pmf. They are really looking strange.
        Stronger restraint means force constant? >From literature, I
        kept it at 3000.


    Those plots do look very strange.  The PMF is almost a step
    function, which is certainly wrong.  You may need either more
    simulation time or more frequent collection of data points, but at
    this stage I can only guess.  Not much more I can offer, sorry.

    A stronger restraint would mean a stronger force constant, yes, but
    if you're using 3000 to restrain simple molecules like methane, I
    think there is no need to increase it.

    -Justin

        On Sun, Nov 20, 2011 at 9:12 PM, Justin A. Lemkul
        <jalem...@vt.edu <mailto:jalem...@vt.edu>
        <mailto:jalem...@vt.edu <mailto:jalem...@vt.edu>>> wrote:



           rajat desikan wrote:

               hi Justin
               I am not able to tell where the lack of overlap is. This
        is the
               first wham plot I am looking at. In your tutorial and
               literature, the wham plots are so clear. Can you please
        help me?
               Thanks.


           It looks like your first one or two windows were not restrained
           sufficiently at the desired distance.  The error complains
        that bin
           2 should have points at 0.366 nm, but it appears neither bin
        1 nor
           bin 2 satisfy this requirement. Check carefully what you have set
           for reference distances and what distances were actually
        maintained
           during the sampling.  You may need a stronger restraint or longer
           simulations.  How long are the simulations?  I see that you're
           starting the analysis on data after 2 ns, but how much does
        that leave?

           -Justin

               On Sat, Nov 19, 2011 at 11:50 PM, rajat desikan
               <rajatdesi...@gmail.com <mailto:rajatdesi...@gmail.com>
        <mailto:rajatdesi...@gmail.com <mailto:rajatdesi...@gmail.com>__>
               <mailto:rajatdesi...@gmail.com
        <mailto:rajatdesi...@gmail.com>

               <mailto:rajatdesi...@gmail.com
        <mailto:rajatdesi...@gmail.com>__>__>> wrote:

                  Oh lovely...thanks for the quick reply Justin :)...


                  On Sat, Nov 19, 2011 at 10:57 PM, Justin A. Lemkul
               <jalem...@vt.edu <mailto:jalem...@vt.edu>
        <mailto:jalem...@vt.edu <mailto:jalem...@vt.edu>>
                  <mailto:jalem...@vt.edu <mailto:jalem...@vt.edu>
        <mailto:jalem...@vt.edu <mailto:jalem...@vt.edu>>>> wrote:



                      rajat desikan wrote:

                          Hi
                          I am a new gromacs user. I just completed Justin's
               umbrella
                          sampling tutorial. I am doing a PMF
        calculation between 2
                          methane molecules in water. The simulation has run
               fine till
                          the g_wham step. My command is

                          -- g_wham -it tpr-files.dat -if
        pullf-files.dat -o -hist
                          -unit kCal -b 2000

                          I get a warning:
                          WARNING, no data point in bin 2 (z=0.366256) !
                          You may not get a reasonable profile. Check your
               histograms!

                          and my histogram contains a single peak.

                          I have pulled my other methane 1 nm away from
        the first
                          methane. I have 15 sampling windows (0.05 nm apart
               till 5nm
                          and then 1 nm apart)...can you please tell me
        how to
               correct
                          this?


                      With 15 windows, you should have 15 histograms.
         Plot with:

                      xmgrace -nxy histo.xvg

                      It will show you where the lack of sampling is.

                      -Justin

-- ==============================______==========



                      Justin A. Lemkul
                      Ph.D. Candidate
                      ICTAS Doctoral Scholar
                      MILES-IGERT Trainee
                      Department of Biochemistry
                      Virginia Tech
                      Blacksburg, VA
                      jalemkul[at]vt.edu <http://vt.edu> <http://vt.edu>
        <http://vt.edu> |
               (540) 231-9080
http://www.bevanlab.biochem.______vt.edu/Pages/Personal/justin
        <http://vt.edu/Pages/Personal/justin>
               <http://vt.edu/Pages/Personal/__justin
        <http://vt.edu/Pages/Personal/justin>>
<http://www.bevanlab.biochem.____vt.edu/Pages/Personal/justin
        <http://vt.edu/Pages/Personal/justin>
<http://www.bevanlab.biochem.__vt.edu/Pages/Personal/justin
        <http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin>>>

                      ==============================______==========


-- gmx-users mailing list gmx-users@gromacs.org <mailto:gmx-users@gromacs.org>
        <mailto:gmx-users@gromacs.org <mailto:gmx-users@gromacs.org>>
                      <mailto:gmx-users@gromacs.org
        <mailto:gmx-users@gromacs.org> <mailto:gmx-users@gromacs.org
        <mailto:gmx-users@gromacs.org>>__>
http://lists.gromacs.org/______mailman/listinfo/gmx-users
        <http://lists.gromacs.org/____mailman/listinfo/gmx-users>
               <http://lists.gromacs.org/____mailman/listinfo/gmx-users
        <http://lists.gromacs.org/__mailman/listinfo/gmx-users>>


<http://lists.gromacs.org/____mailman/listinfo/gmx-users
        <http://lists.gromacs.org/__mailman/listinfo/gmx-users>
               <http://lists.gromacs.org/__mailman/listinfo/gmx-users
        <http://lists.gromacs.org/mailman/listinfo/gmx-users>>>
                      Please search the archive at
http://www.gromacs.org/______Support/Mailing_Lists/Search
        <http://www.gromacs.org/____Support/Mailing_Lists/Search>
               <http://www.gromacs.org/____Support/Mailing_Lists/Search
        <http://www.gromacs.org/__Support/Mailing_Lists/Search>>


<http://www.gromacs.org/____Support/Mailing_Lists/Search
        <http://www.gromacs.org/__Support/Mailing_Lists/Search>
               <http://www.gromacs.org/__Support/Mailing_Lists/Search
        <http://www.gromacs.org/Support/Mailing_Lists/Search>>> before
                      posting!
                      Please don't post (un)subscribe requests to the
        list. Use the
                      www interface or send it to
        gmx-users-requ...@gromacs.org <mailto:gmx-users-requ...@gromacs.org>
               <mailto:gmx-users-request@__gromacs.org
        <mailto:gmx-users-requ...@gromacs.org>>
                      <mailto:gmx-users-request@
        <mailto:gmx-users-request@>__gr__omacs.org <http://gromacs.org>

               <mailto:gmx-users-request@__gromacs.org
        <mailto:gmx-users-requ...@gromacs.org>>>.
                      Can't post? Read
               http://www.gromacs.org/______Support/Mailing_Lists
        <http://www.gromacs.org/____Support/Mailing_Lists>
               <http://www.gromacs.org/____Support/Mailing_Lists
        <http://www.gromacs.org/__Support/Mailing_Lists>>


                      <http://www.gromacs.org/____Support/Mailing_Lists
        <http://www.gromacs.org/__Support/Mailing_Lists>
               <http://www.gromacs.org/__Support/Mailing_Lists
        <http://www.gromacs.org/Support/Mailing_Lists>>>




                  --     Rajat Desikan (Ph.D Scholar)
                  Prof. K. Ganapathy Ayappa's Lab (no 13),
                  Dept. of Chemical Engineering,
                  Indian Institute of Science, Bangalore




               --         Rajat Desikan (Ph.D Scholar)
               Prof. K. Ganapathy Ayappa's Lab (no 13),
               Dept. of Chemical Engineering,
               Indian Institute of Science, Bangalore

------------------------------____----------------------------__--__------------



           --     ==============================____==========

           Justin A. Lemkul
           Ph.D. Candidate
           ICTAS Doctoral Scholar
           MILES-IGERT Trainee
           Department of Biochemistry
           Virginia Tech
           Blacksburg, VA
           jalemkul[at]vt.edu <http://vt.edu> <http://vt.edu> | (540)
        231-9080
           http://www.bevanlab.biochem.____vt.edu/Pages/Personal/justin
        <http://vt.edu/Pages/Personal/justin>
           <http://www.bevanlab.biochem.__vt.edu/Pages/Personal/justin
        <http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin>>

           ==============================____==========
           --     gmx-users mailing list    gmx-users@gromacs.org
        <mailto:gmx-users@gromacs.org>
           <mailto:gmx-users@gromacs.org <mailto:gmx-users@gromacs.org>>
           http://lists.gromacs.org/____mailman/listinfo/gmx-users
        <http://lists.gromacs.org/__mailman/listinfo/gmx-users>
           <http://lists.gromacs.org/__mailman/listinfo/gmx-users
        <http://lists.gromacs.org/mailman/listinfo/gmx-users>>
           Please search the archive at
           http://www.gromacs.org/____Support/Mailing_Lists/Search
        <http://www.gromacs.org/__Support/Mailing_Lists/Search>
           <http://www.gromacs.org/__Support/Mailing_Lists/Search
        <http://www.gromacs.org/Support/Mailing_Lists/Search>> before
        posting!
           Please don't post (un)subscribe requests to the list. Use the www
           interface or send it to gmx-users-requ...@gromacs.org
        <mailto:gmx-users-requ...@gromacs.org>
           <mailto:gmx-users-request@__gromacs.org
        <mailto:gmx-users-requ...@gromacs.org>>.
           Can't post? Read
        http://www.gromacs.org/____Support/Mailing_Lists
        <http://www.gromacs.org/__Support/Mailing_Lists>
           <http://www.gromacs.org/__Support/Mailing_Lists
        <http://www.gromacs.org/Support/Mailing_Lists>>




-- Rajat Desikan (Ph.D Scholar)
        Prof. K. Ganapathy Ayappa's Lab (no 13),
        Dept. of Chemical Engineering,
        Indian Institute of Science, Bangalore

        
------------------------------__------------------------------__------------


        
------------------------------__------------------------------__------------


-- ==============================__==========

    Justin A. Lemkul
    Ph.D. Candidate
    ICTAS Doctoral Scholar
    MILES-IGERT Trainee
    Department of Biochemistry
    Virginia Tech
    Blacksburg, VA
    jalemkul[at]vt.edu <http://vt.edu> | (540) 231-9080
    http://www.bevanlab.biochem.__vt.edu/Pages/Personal/justin
    <http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin>

    ==============================__==========
-- gmx-users mailing list gmx-users@gromacs.org
    <mailto:gmx-users@gromacs.org>
    http://lists.gromacs.org/__mailman/listinfo/gmx-users
    <http://lists.gromacs.org/mailman/listinfo/gmx-users>
    Please search the archive at
    http://www.gromacs.org/__Support/Mailing_Lists/Search
    <http://www.gromacs.org/Support/Mailing_Lists/Search> before posting!
    Please don't post (un)subscribe requests to the list. Use the www
    interface or send it to gmx-users-requ...@gromacs.org
    <mailto:gmx-users-requ...@gromacs.org>.
    Can't post? Read http://www.gromacs.org/__Support/Mailing_Lists
    <http://www.gromacs.org/Support/Mailing_Lists>




--
Rajat Desikan (Ph.D Scholar)
Prof. K. Ganapathy Ayappa's Lab (no 13),
Dept. of Chemical Engineering,
Indian Institute of Science, Bangalore

--
========================================

Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

========================================
--
gmx-users mailing list    gmx-users@gromacs.org
http://lists.gromacs.org/mailman/listinfo/gmx-users
Please search the archive at 
http://www.gromacs.org/Support/Mailing_Lists/Search before posting!
Please don't post (un)subscribe requests to the list. Use the www interface or send it to gmx-users-requ...@gromacs.org.
Can't post? Read http://www.gromacs.org/Support/Mailing_Lists

Reply via email to