def get_double_or_single_prec_mdrun():
"""Return double precision ``mdrun`` or fall back to single precision.
This convenience function tries :func:`gromacs.mdrun_d` first and
if it cannot run it, falls back to :func:`gromacs.mdrun` (without
further checking).
.. versionadded:: 0.5.1
"""
try:
gromacs.mdrun_d(h=True, stdout=False, stderr=False)
logger.debug("using double precision gromacs.mdrun_d")
return gromacs.mdrun_d
except (AttributeError, GromacsError, OSError):
# fall back to mdrun if no double precision binary
wmsg = "No 'mdrun_d' binary found so trying 'mdrun' instead.\n"\
"(Note that energy minimization runs better with mdrun_d.)"
logger.warn(wmsg)
warnings.warn(wmsg, category=AutoCorrectionWarning)
return gromacs.mdrun
def energy_minimize(dirname='em', mdp=config.templates['em.mdp'],
struct='solvate/ionized.pdb', top='top/system.top',
output='em.pdb', deffnm="em",
mdrunner=None, **kwargs):
"""Energy minimize the system.
This sets up the system (creates run input files) and also runs
``mdrun_d``. Thus it can take a while.
Additional itp files should be in the same directory as the top file.
Many of the keyword arguments below already have sensible values.
:Keywords:
*dirname*
set up under directory dirname [em]
*struct*
input structure (gro, pdb, ...) [solvate/ionized.pdb]
*output*
output structure (will be put under dirname) [em.pdb]
*deffnm*
default name for mdrun-related files [em]
*top*
topology file [top/system.top]
*mdp*
mdp file (or use the template) [templates/em.mdp]
*includes*
additional directories to search for itp files
*mdrunner*
:class:`gromacs.run.MDrunner` class; by defauly we
just try :func:`gromacs.mdrun_d` and :func:`gromacs.mdrun` but a
MDrunner class gives the user the ability to run mpi jobs
etc. [None]
*kwargs*
remaining key/value pairs that should be changed in the
template mdp file, eg ``nstxtcout=250, nstfout=250``.
.. note:: If :func:`~gromacs.mdrun_d` is not found, the function
falls back to :func:`~gromacs.mdrun` instead.
"""
structure = realpath(struct)
topology = realpath(top)
mdp_template = config.get_template(mdp)
deffnm = deffnm.strip()
# write the processed topology to the default output
kwargs.setdefault('pp', 'processed.top')
# filter some kwargs that might come through when feeding output
# from previous stages such as solvate(); necessary because *all*
# **kwargs must be *either* substitutions in the mdp file *or* valid
# command line parameters for ``grompp``.
kwargs.pop('ndx', None)
# mainselection is not used but only passed through; right now we
# set it to the default that is being used in all argument lists
# but that is not pretty. TODO.
mainselection = kwargs.pop('mainselection', '"Protein"')
# only interesting when passed from solvate()
qtot = kwargs.pop('qtot', 0)
mdp = deffnm+'.mdp'
tpr = deffnm+'.tpr'
logger.info("[%(dirname)s] Energy minimization of struct=%(struct)r, top=%(top)r, mdp=%(mdp)r ..." % vars())
add_mdp_includes(topology, kwargs)
if qtot != 0:
# At the moment this is purely user-reported and really only here because
# it might get fed into the function when using the keyword-expansion pipeline
# usage paradigm.
wmsg = "Total charge was reported as qtot = %(qtot)g <> 0; probably a problem." % vars()
logger.warn(wmsg)
warnings.warn(wmsg, category=BadParameterWarning)
with in_dir(dirname):
unprocessed = gromacs.cbook.edit_mdp(mdp_template, new_mdp=mdp, **kwargs)
check_mdpargs(unprocessed)
gromacs.grompp(f=mdp, o=tpr, c=structure, p=topology, **unprocessed)
mdrun_args = dict(v=True, stepout=10, deffnm=deffnm, c=output)
if mdrunner is None:
try:
gromacs.mdrun_d(**mdrun_args)
except (AttributeError, OSError):
# fall back to mdrun if no double precision binary
wmsg = "No 'mdrun_d' binary found so trying 'mdrun' instead.\n"\
"(Note that energy minimization runs better with mdrun_d.)"
logger.warn(wmsg)
warnings.warn(wmsg, category=AutoCorrectionWarning)
gromacs.mdrun(**mdrun_args)
else:
# user wants full control and provides simulation.MDrunner **class**
# NO CHECKING --- in principle user can supply any callback they like
mdrun = mdrunner(**mdrun_args)
mdrun.run()
# em.gro --> gives 'Bad box in file em.gro' warning --- why??
# --> use em.pdb instead.
if not os.path.exists(output):
errmsg = "Energy minimized system NOT produced."
logger.error(errmsg)
raise GromacsError(errmsg)
final_struct = realpath(output)
logger.info("[%(dirname)s] energy minimized structure %(final_struct)r" % vars())
return {'struct': final_struct,
'top': topology,
'mainselection': mainselection,
}