.. _gmx convert-tpr:

gmx convert-tpr
===============

Synopsis
--------

.. parsed-literal::

    gmx convert-tpr [:strong:`-s` :emphasis:`[<.tpr>]`] [:strong:`-n` :emphasis:`[<.ndx>]`] [:strong:`-o` :emphasis:`[<.tpr>]`]
                 [:strong:`-extend` :emphasis:`<real>`] [:strong:`-until` :emphasis:`<real>`] [:strong:`-nsteps` :emphasis:`<int>`]
                 [:strong:`-[no]zeroq`]

Description
-----------

``gmx convert-tpr`` can edit run input files in three ways.

**1.** by modifying the number of steps in a run input file
with options ``-extend``, ``-until`` or ``-nsteps``
(nsteps=-1 means unlimited number of steps)

**2.** by creating a .tpx file for a subset of your original
tpx file, which is useful when you want to remove the solvent from
your .tpx file, or when you want to make e.g. a pure Calpha .tpx file.
Note that you may need to use ``-nsteps -1`` (or similar) to get
this to work.
**WARNING: this .tpx file is not fully functional**.

**3.** by setting the charges of a specified group
to zero. This is useful when doing free energy estimates
using the LIE (Linear Interaction Energy) method.

Options
-------

Options to specify input files:

``-s`` [<.tpr>] (topol.tpr)
    Portable xdr run input file
``-n`` [<.ndx>] (index.ndx) (Optional)
    Index file

Options to specify output files:

``-o`` [<.tpr>] (tprout.tpr)
    Portable xdr run input file

Other options:

``-extend`` <real> (0)
    Extend runtime by this amount (ps)
``-until`` <real> (0)
    Extend runtime until this ending time (ps)
``-nsteps`` <int> (0)
    Change the number of steps
``-[no]zeroq``  (no)
    Set the charges of a group (from the index) to zero

.. only:: man

   See also
   --------

   :manpage:`gmx(1)`

   More information about |Gromacs| is available at <http://www.gromacs.org/>.