Any of the 3 quantities defining the E-field components can be -specified as an equal-style or atom-style variable, namely -ex, ey, ez. If the value is a variable, it should be specified -as v_ID, where ID is the variable ID. In this case, the variable will -be evaluated each timestep, and its value used to determine the -E-field component. +specified as an equal-style or atom-style variable, +namely ex, ey, ez. If the value is a variable, it should be +specified as v_ID, where ID is the variable ID. In this case, the +variable will be evaluated each timestep, and its value used to +determine the E-field component.
Equal-style variables can specify formulas with various mathematical functions, and include thermo_style command diff --git a/doc/fix_efield.txt b/doc/fix_efield.txt index d62757f415..3cb4801cb1 100644 --- a/doc/fix_efield.txt +++ b/doc/fix_efield.txt @@ -28,11 +28,11 @@ Add a force F = qE to each charged atom in the group due to an external electric field being applied to the system. Any of the 3 quantities defining the E-field components can be -specified as an equal-style or atom-style "variable"_variable, namely -{ex}, {ey}, {ez}. If the value is a variable, it should be specified -as v_ID, where ID is the variable ID. In this case, the variable will -be evaluated each timestep, and its value used to determine the -E-field component. +specified as an equal-style or atom-style "variable"_variable.html, +namely {ex}, {ey}, {ez}. If the value is a variable, it should be +specified as v_ID, where ID is the variable ID. In this case, the +variable will be evaluated each timestep, and its value used to +determine the E-field component. Equal-style variables can specify formulas with various mathematical functions, and include "thermo_style"_thermo_style.html command diff --git a/doc/minimize.html b/doc/minimize.html index 0b7a145c40..62ffb44c9a 100644 --- a/doc/minimize.html +++ b/doc/minimize.html @@ -151,13 +151,22 @@ reduced.
IMPORTANT NOTE: It is highly recommended that you use a pair -style that goes to 0.0 at the cutoff distance when -performing minimization (even if you later change it when running -dynamics). If this is not done, the total energy of the system will -have discontinuities when the relative distance between any pair of -atoms changes from cutoff+epsilon to cutoff-epsilon and the minimizer -may behave poorly. +
IMPORTANT NOTE: There are several force fields in LAMMPS which have +discontinuities or other approximations which may prevent you from +performing an energy minimization to high tolerances. For example, +you should use a pair style that goes to 0.0 at the +cutoff distance when performing minimization (even if you later change +it when running dynamics). If you do not do this, the total energy of +the system will have discontinuities when the relative distance +between any pair of atoms changes from cutoff+epsilon to +cutoff-epsilon and the minimizer may behave poorly. Some of the +manybody potentials use splines and other internal cutoffs that +inherently have this problem. The long-range Coulombic +styles (PPPM, Ewald) are approximate to within the +user-specified tolerance, which means their energy and forces may not +agree to a higher precision than the Kspace-specified tolerance. In +all these cases, the minimizer may give up and stop before finding a +minimum to the specified energy or force tolerance.
Note that a cutoff Lennard-Jones potential (and others) can be shifted so that its energy is 0.0 at the cutoff via the diff --git a/doc/minimize.txt b/doc/minimize.txt index a37c063aef..5302f233f1 100644 --- a/doc/minimize.txt +++ b/doc/minimize.txt @@ -148,13 +148,22 @@ The iterations and force evaluation values are what is checked by the :line -IMPORTANT NOTE: It is highly recommended that you use a "pair -style"_pair_style.html that goes to 0.0 at the cutoff distance when -performing minimization (even if you later change it when running -dynamics). If this is not done, the total energy of the system will -have discontinuities when the relative distance between any pair of -atoms changes from cutoff+epsilon to cutoff-epsilon and the minimizer -may behave poorly. +IMPORTANT NOTE: There are several force fields in LAMMPS which have +discontinuities or other approximations which may prevent you from +performing an energy minimization to high tolerances. For example, +you should use a "pair style"_pair_style.html that goes to 0.0 at the +cutoff distance when performing minimization (even if you later change +it when running dynamics). If you do not do this, the total energy of +the system will have discontinuities when the relative distance +between any pair of atoms changes from cutoff+epsilon to +cutoff-epsilon and the minimizer may behave poorly. Some of the +manybody potentials use splines and other internal cutoffs that +inherently have this problem. The "long-range Coulombic +styles"_kspace_style.html (PPPM, Ewald) are approximate to within the +user-specified tolerance, which means their energy and forces may not +agree to a higher precision than the Kspace-specified tolerance. In +all these cases, the minimizer may give up and stop before finding a +minimum to the specified energy or force tolerance. Note that a cutoff Lennard-Jones potential (and others) can be shifted so that its energy is 0.0 at the cutoff via the diff --git a/src/fix_box_relax.cpp b/src/fix_box_relax.cpp index a50f6a0bd8..7f1794cfd1 100644 --- a/src/fix_box_relax.cpp +++ b/src/fix_box_relax.cpp @@ -24,6 +24,7 @@ #include "update.h" #include "comm.h" #include "force.h" +#include "kspace.h" #include "modify.h" #include "compute.h" #include "error.h" @@ -318,6 +319,9 @@ void FixBoxRelax::init() pv2e = 1.0 / force->nktv2p; + if (force->kspace) kspace_flag = 1; + else kspace_flag = 0; + // detect if any rigid fixes exist so rigid bodies move when box is remapped // rfix[] = indices to each fix rigid @@ -528,6 +532,7 @@ void FixBoxRelax::min_step(double alpha, double *hextra) } } remap(); + if (kspace_flag) force->kspace->setup(); } /* ---------------------------------------------------------------------- diff --git a/src/fix_box_relax.h b/src/fix_box_relax.h index 33230131ff..590412e9e1 100644 --- a/src/fix_box_relax.h +++ b/src/fix_box_relax.h @@ -50,6 +50,7 @@ class FixBoxRelax : public Fix { double p_target[6],p_current[6]; double vol0,xprdinit,yprdinit,zprdinit; double vmax,pv2e,pflagsum; + int kspace_flag; int current_lifo; // LIFO stack pointer double boxlo0[2][3]; // box bounds at start of line search diff --git a/src/min_linesearch.cpp b/src/min_linesearch.cpp index b94afa3337..6eb96cbec8 100644 --- a/src/min_linesearch.cpp +++ b/src/min_linesearch.cpp @@ -409,7 +409,7 @@ int MinLineSearch::linemin_quadratic(double eoriginal, double &alpha, // double alphatmp = alphamax*1.0e-4; // etmp = alpha_step(alphatmp,1,nfunc); // printf("alpha = %g dele = %g dele_force = %g err = %g\n", - // alphatmp,etmp-eoriginal,-alphatmp*fdothall, + // alphatmp,etmp-eoriginal,-alphatmp*fdothall, // etmp-eoriginal+alphatmp*fdothall); // alpha_step(0.0,1,nfunc); @@ -462,13 +462,15 @@ int MinLineSearch::linemin_quadratic(double eoriginal, double &alpha, relerr = fabs(1.0-(0.5*(alpha-alphaprev)*(fh+fhprev)+ecurrent)/engprev); alpha0 = alpha - (alpha-alphaprev)*fh/delfh; - if (relerr <= QUADRATIC_TOL && alpha0 > 0.0) { + if (relerr <= QUADRATIC_TOL && alpha0 > 0.0 && alpha0 < alphamax) { ecurrent = alpha_step(alpha0,1,nfunc); - if (nextra_global) { - int itmp = modify->min_reset_ref(); - if (itmp) ecurrent = energy_force(1); + if (ecurrent < eoriginal) { + if (nextra_global) { + int itmp = modify->min_reset_ref(); + if (itmp) ecurrent = energy_force(1); + } + return 0; } - return 0; } // if backtracking energy change is better than ideal, exit with success diff --git a/src/version.h b/src/version.h index 8099d3e26c..3ee0aa3f1e 100644 --- a/src/version.h +++ b/src/version.h @@ -1 +1 @@ -#define LAMMPS_VERSION "26 Apr 2010" +#define LAMMPS_VERSION "27 Apr 2010"