proposed SJP changes for 2nd cutoff_triple (937d4707) · Commits · 郑智淋 / lammps

doc/src/pair_atm.txt

+12 −5

Original line number	Diff line number	Diff line
		@@ -10,16 +10,20 @@ pair_style atm command :h3

		[Syntax:]

		pair_style atm cutoff :pre
		SJP: add an arg

		cutoff = global cutoff for 3-body interactions (distance units) :ul
		pair_style atm cutoff cutoff_triple :pre

		cutoff = cutoff for each pair in 3-body interaction (distance units)
		cutoff_triple = additional cutoff applied to product of 3 pairwise distances (distance units) :ul

		[Examples:]

		pair_style atm 2.5
		SJP: is 1.5 a good value?
		pair_style atm 2.5 1.5
		pair_coeff * * * 0.072 :pre

		pair_style hybrid/overlay lj/cut 6.5 atm 2.5
		pair_style hybrid/overlay lj/cut 6.5 atm 2.5 1.5
		pair_coeff * * lj/cut 1.0 1.0
		pair_coeff 1 1 atm 1 0.064
		pair_coeff 1 1 atm 2 0.080
		@@ -50,7 +54,10 @@ potential using the "pair_style hybrid/overlay"_pair_hybrid.html
		command as in the example above.

		The potential for a triplet of atom is calculated only if all 3
		distances r12, r23, r31 between the 3 atoms satisfy rIJ < cutoff
		distances r12, r23, r31 between the 3 atoms satisfy rIJ < cutoff.
		SJP: In addition, the product of the 3 distances r12r23r31 <
		cutoff_triple^3 is required, which limits the contribution of the
		potential to ???

		The following coefficients must be defined for each pair of atoms
		types via the "pair_coeff"_pair_coeff.html command as in the examples

src/MANYBODY/pair_atm.cpp

+22 −2

Original line number	Diff line number	Diff line
		@@ -92,6 +92,10 @@ void PairATM::compute(int eflag, int vflag)
		int *type = atom->type;

		double cutoff_squared = cut_global*cut_global;
		// SJP: new cutoff
		double triple = cut_triplecut_triplecut_triple;
		double cutoff_triple_sixth = triple*triple;

		inum = list->inum;
		ilist = list->ilist;
		numneigh = list->numneigh;
		@@ -138,6 +142,10 @@ void PairATM::compute(int eflag, int vflag)
		rik2 = rik[0]rik[0] + rik[1]rik[1] + rik[2]*rik[2];
		if (rik2 > cutoff_squared) continue;

		// SJP: add this line?

		if (rij2rjk2rik2 > cutoff_triple_sixth) continue;

		nu_local = nu[type[i]][type[j]][type[k]];
		if (nu_local == 0.0) continue;

		@@ -192,9 +200,14 @@ void PairATM::allocate()

		void PairATM::settings(int narg, char **arg)
		{
		if (narg != 1) error->all(FLERR,"Illegal pair_style command");
		// SJP: change to 2 args, require triple <= global

		if (narg != 2) error->all(FLERR,"Illegal pair_style command");

		cut_global = force->numeric(FLERR,arg[0]);
		cut_triple = force->numeric(FLERR,arg[1]);

		if (cut_triple > cut_global) error->all(FLERR,"Illegal pair_style command");
		}

		/* ----------------------------------------------------------------------
		@@ -311,6 +324,8 @@ void PairATM::read_restart(FILE *fp)
		void PairATM::write_restart_settings(FILE *fp)
		{
		fwrite(&cut_global,sizeof(double),1,fp);
		// SJP: 2nd arg
		fwrite(&cut_triple,sizeof(double),1,fp);
		}

		/* ----------------------------------------------------------------------
		@@ -319,9 +334,14 @@ void PairATM::write_restart_settings(FILE *fp)

		void PairATM::read_restart_settings(FILE *fp)
		{
		// SJP: 2nd arg
		int me = comm->me;
		if (me == 0) fread(&cut_global,sizeof(double),1,fp);
		if (me == 0) {
		fread(&cut_global,sizeof(double),1,fp);
		fread(&cut_triple,sizeof(double),1,fp);
		}
		MPI_Bcast(&cut_global,1,MPI_DOUBLE,0,world);
		MPI_Bcast(&cut_triple,1,MPI_DOUBLE,0,world);
		}

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

src/MANYBODY/pair_atm.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -39,7 +39,8 @@ class PairATM : public Pair {
		void read_restart_settings(FILE *);

		protected:
		double cut_global, cutoff_squared;
		// SJP: add 2nd cutoff
		double cut_global,cut_triple;
		double ***nu;

		void allocate();

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