Allow fix python to only execute every N steps (c4d0f070) · Commits · 郑智淋 / lammps

doc/src/fix_python.txt

+7 −6

Original line number	Diff line number	Diff line
		@@ -10,13 +10,14 @@ fix python command :h3

		[Syntax:]

		fix ID group-ID python callback function_name :pre
		fix ID group-ID python N callback function_name :pre

		ID, group-ID are ignored by this fix :ulb,l
		python = style name of this fix command :l
		N = execute every N steps :l
		callback = {post_force} or {end_of_step} :l
		{post_force} = callback after force computations on atoms
		{end_of_step} = callback after each time step :pre
		{post_force} = callback after force computations on atoms every N time steps
		{end_of_step} = callback after each N time steps :pre
		:ule

		[Examples:]
		@@ -35,14 +36,14 @@ def end_of_step_callback(lammps_ptr):
		# access LAMMPS state using Python interface
		""" :pre

		fix pf all python post_force post_force_callback
		fix eos all python end_of_step end_of_step_callback :pre
		fix pf all python 50 post_force post_force_callback
		fix eos all python 50 end_of_step end_of_step_callback :pre

		[Description:]

		This fix allows you to call a Python function during a simulation run.
		The callback is either executed after forces have been applied to atoms
		or at the end of each time step.
		or at the end of every N time steps.

		Callback functions must be declared in the global scope of the
		active Python interpreter. This can either be done by defining it

+2 −2

Original line number	Diff line number	Diff line
		@@ -33,8 +33,8 @@ def post_force_callback(lmp, v):
		"""

		fix 1 all nve
		fix 2 all python end_of_step end_of_step_callback
		fix 3 all python post_force post_force_callback
		fix 2 all python 50 end_of_step end_of_step_callback
		fix 3 all python 50 post_force post_force_callback

		#dump id all atom 50 dump.melt

+9 −4

Original line number	Diff line number	Diff line
		@@ -36,14 +36,17 @@ using namespace FixConst;
		FixPython::FixPython(LAMMPS lmp, int narg, char *arg) :
		Fix(lmp, narg, arg)
		{
		if (narg != 5) error->all(FLERR,"Illegal fix python command");
		if (narg != 6) error->all(FLERR,"Illegal fix python command");

		nevery = force->inumeric(FLERR,arg[3]);
		if (nevery <= 0) error->all(FLERR,"Illegal fix python command");

		// ensure Python interpreter is initialized
		python->init();

		if (strcmp(arg[3],"post_force") == 0) {
		if (strcmp(arg[4],"post_force") == 0) {
		selected_callback = POST_FORCE;
		} else if (strcmp(arg[3],"end_of_step") == 0) {
		} else if (strcmp(arg[4],"end_of_step") == 0) {
		selected_callback = END_OF_STEP;
		}

		@@ -57,7 +60,7 @@ FixPython::FixPython(LAMMPS lmp, int narg, char *arg) :
		error->all(FLERR,"Could not initialize embedded Python");
		}

		char * fname = arg[4];
		char * fname = arg[5];
		pFunc = PyObject_GetAttrString(pyMain, fname);

		if (!pFunc) {
		@@ -94,6 +97,8 @@ void FixPython::end_of_step()

		void FixPython::post_force(int vflag)
		{
		if (update->ntimestep % nevery != 0) return;

		PyGILState_STATE gstate = PyGILState_Ensure();

		PyObject * ptr = PY_VOID_POINTER(lmp);