Merge pull request #211 from akohlmey/add-respa-to-fix-flow-gauss (ed8cc827) · Commits · 郑智淋 / lammps

doc/src/fix_flow_gauss.txt

+19 −1

Original line number	Diff line number	Diff line
		@@ -63,7 +63,7 @@ applied by GD before computing a pressure drop or comparing it to
		other methods, such as the pump method "(Zhu)"_#Zhu. The pressure
		correction is discussed and described in "(Strong)"_#Strong.

		NOTE: For a complete example including the considerations discussed
		For a complete example including the considerations discussed
		above, see the examples/USER/flow_gauss directory.

		NOTE: Only the flux of the atoms in group-ID will be conserved. If the
		@@ -93,6 +93,19 @@ work on the system must have {fix_modify energy yes} set as well. This
		includes thermostat fixes and any constraints that hold the positions
		of wall atoms fixed, such as "fix spring/self"_fix_spring_self.html.

		If this fix is used in a simulation with the "rRESPA"_run_style.html
		integrator, the applied acceleration must be computed and applied at the same
		rRESPA level as the interactions between the flowing fluid and the obstacle.
		The rRESPA level at which the acceleration is applied can be changed using
		the "fix_modify"_fix_modify.html {respa} option discussed below. If the
		flowing fluid and the obstacle interact through multiple interactions that are
		computed at different rRESPA levels, then there must be a separate flow/gauss
		fix for each level. For example, if the flowing fluid and obstacle interact
		through pairwise and long-range Coulomb interactions, which are computed at
		rRESPA levels 3 and 4, respectively, then there must be two separate
		flow/gauss fixes, one that specifies {fix_modify respa 3} and one with
		{fix_modify respa 4}.

		:line

		[Restart, fix_modify, output, run start/stop, minimize info:]
		@@ -109,6 +122,11 @@ fix to subtract the work done from the
		system's potential energy as part of "thermodynamic
		output"_thermo_style.html.

		The "fix_modify"_fix_modify.html {respa} option is supported by this
		fix. This allows the user to set at which level of the "rRESPA"_run_style.html
		integrator the fix computes and adds the external acceleration. Default is the
		outermost level.

		This fix computes a global scalar and a global 3-vector of forces,
		which can be accessed by various "output
		commands"_Section_howto.html#howto_15. The scalar is the negative of the

src/USER-MISC/fix_flow_gauss.cpp

+29 −2

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@
		#include "domain.h"
		#include "error.h"
		#include "citeme.h"
		#include "respa.h"

		using namespace LAMMPS_NS;
		using namespace FixConst;
		@@ -63,6 +64,8 @@ FixFlowGauss::FixFlowGauss(LAMMPS lmp, int narg, char *arg) :
		extvector = 1;
		size_vector = 3;
		global_freq = 1; //data available every timestep
		respa_level_support = 1;
		//default respa level=outermost level is set in init()

		dimension = domain->dimension;

		@@ -109,9 +112,23 @@ int FixFlowGauss::setmask()
		int mask = 0;
		mask \|= POST_FORCE;
		mask \|= THERMO_ENERGY;
		mask \|= POST_FORCE_RESPA;
		return mask;
		}

		/* ---------------------------------------------------------------------- */

		void FixFlowGauss::init()
		{
		//if respa level specified by fix_modify, then override default (outermost)
		//if specified level too high, set to max level
		if (strstr(update->integrate_style,"respa")) {
		ilevel_respa = ((Respa *) update->integrate)->nlevels-1;
		if (respa_level >= 0)
		ilevel_respa = MIN(respa_level,ilevel_respa);
		}
		}

		/* ----------------------------------------------------------------------
		setup is called after the initial evaluation of forces before a run, so we
		must remove the total force here too
		@@ -127,6 +144,12 @@ void FixFlowGauss::setup(int vflag)
		if (mTot <= 0.0)
		error->all(FLERR,"Invalid group mass in fix flow/gauss");

		if (strstr(update->integrate_style,"respa")) {
		((Respa *) update->integrate)->copy_flevel_f(ilevel_respa);
		post_force_respa(vflag,ilevel_respa,0);
		((Respa *) update->integrate)->copy_f_flevel(ilevel_respa);
		}
		else
		post_force(vflag);
		}

		@@ -148,7 +171,6 @@ void FixFlowGauss::post_force(int vflag)
		int ii,jj;

		//find the total force on all atoms

		//initialize to zero
		double f_thisProc[3];
		for (ii=0; ii<3; ii++)
		@@ -201,6 +223,11 @@ void FixFlowGauss::post_force(int vflag)

		}

		void FixFlowGauss::post_force_respa(int vflag, int ilevel, int iloop)
		{
		if (ilevel == ilevel_respa) post_force(vflag);
		}

		/* ----------------------------------------------------------------------
		negative of work done by this fix
		This is only computed if requested, either with fix_modify energy yes, or with the energy keyword. Otherwise returns 0.

src/USER-MISC/fix_flow_gauss.h

+5 −2

Original line number	Diff line number	Diff line
		@@ -30,10 +30,12 @@ FixStyle(flow/gauss,FixFlowGauss)
		public:
		FixFlowGauss(class LAMMPS , int, char *);
		int setmask();
		void init();
		void setup(int);
		void post_force(int);
		void post_force_respa(int, int, int);
		double compute_scalar();
		double compute_vector(int n);
		void post_force(int);
		void setup(int);

		protected:
		int dimension;
		@@ -44,6 +46,7 @@ FixStyle(flow/gauss,FixFlowGauss)
		double pe_tot; //total added energy
		double dt; //timestep
		bool workflag; //if calculate work done by fix
		int ilevel_respa;

		};

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