Make omega_mass proportional to (N+1)kT (d0ba8e1d) · Commits · 郑智淋 / lammps

According to papers like Martyna, Tobias, Klein (JCP 1994, doi:10.1063/1.467468 section II.F) and Martyna, Tuckerman, Tobias, Klein (Mol. Phys. 1996, doi:10.1080/00268979600100761 section 2.5), the mass of the cell parameters should be proportional to (Ndof + dim) / dim, or in other words, Natoms + 1.

src/fix_nh.cpp

+2 −2

Original line number	Diff line number	Diff line
		@@ -798,7 +798,7 @@ void FixNH::setup(int vflag)

		if (pstat_flag) {
		double kt = boltz * t_target;
		double nkt = atom->natoms * kt;
		double nkt = (atom->natoms + 1) * kt;

		for (int i = 0; i < 3; i++)
		if (p_flag[i])
		@@ -1826,7 +1826,7 @@ void FixNH::nhc_press_integrate()
		// Update masses, to preserve initial freq, if flag set

		if (omega_mass_flag) {
		double nkt = atom->natoms * kt;
		double nkt = (atom->natoms + 1) * kt;
		for (int i = 0; i < 3; i++)
		if (p_flag[i])
		omega_mass[i] = nkt/(p_freq[i]*p_freq[i]);

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