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git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@2490 f3b2605a-c512-4ea7-a41b-209d697bcdaa

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This commit is contained in:
sjplimp
2009-01-16 14:35:23 +00:00
parent 21d6d5ddb3
commit 5553870174
2 changed files with 40 additions and 6 deletions
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41
src/fix_spring.cpp
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@ -37,9 +37,11 @@ FixSpring::FixSpring(LAMMPS *lmp, int narg, char **arg) :
{
if (narg < 9) error->all("Illegal fix spring command");
scalar_flag = 1;
vector_flag = 1;
size_vector = 3;
scalar_vector_freq = 1;
extscalar = 1;
extvector = 1;
if (strcmp(arg[3],"tether") == 0) {
@ -88,7 +90,9 @@ int FixSpring::setmask()
{
int mask = 0;
mask |= POST_FORCE;
mask |= THERMO_ENERGY;
mask |= POST_FORCE_RESPA;
mask |= MIN_POST_FORCE;
return mask;
}
@ -118,6 +122,13 @@ void FixSpring::setup(int vflag)
/* ---------------------------------------------------------------------- */
void FixSpring::min_setup(int vflag)
{
post_force(vflag);
}
/* ---------------------------------------------------------------------- */
void FixSpring::post_force(int vflag)
{
if (styleflag == TETHER) spring_tether();
@ -143,10 +154,12 @@ void FixSpring::spring_tether()
if (!zflag) dz = 0.0;
r = sqrt(dx*dx + dy*dy + dz*dz);
dr = r - r0;
fx = k_spring*dx*dr/r;
fy = k_spring*dy*dr/r;
fz = k_spring*dz*dr/r;
espring = 0.5*k_spring * dr*dr;
// apply restoring force to atoms in group
// f = -k*(r-r0)*mass/masstotal
@ -195,6 +208,7 @@ void FixSpring::spring_couple()
fx = k_spring*dx*dr/r;
fy = k_spring*dy*dr/r;
fz = k_spring*dz*dr/r;
espring = 0.5*k_spring * dr*dr;
// apply restoring force to atoms in group
// f = -k*(r-r0)*mass/masstotal
@ -221,10 +235,10 @@ void FixSpring::spring_couple()
}
}
ftotal[0] = -fx;
ftotal[1] = -fy;
ftotal[2] = -fz;
force_flag = 0;
ftotal[0] = fx;
ftotal[1] = fy;
ftotal[2] = fz;
force_flag = 1;
}
/* ---------------------------------------------------------------------- */
@ -234,6 +248,22 @@ void FixSpring::post_force_respa(int vflag, int ilevel, int iloop)
if (ilevel == nlevels_respa-1) post_force(vflag);
}
/* ---------------------------------------------------------------------- */
void FixSpring::min_post_force(int vflag)
{
post_force(vflag);
}
/* ----------------------------------------------------------------------
energy of stretched spring
------------------------------------------------------------------------- */
double FixSpring::compute_scalar()
{
return espring;
}
/* ----------------------------------------------------------------------
return components of total spring force on fix group
------------------------------------------------------------------------- */
@ -241,6 +271,7 @@ void FixSpring::post_force_respa(int vflag, int ilevel, int iloop)
double FixSpring::compute_vector(int n)
{
// only sum across procs one time
// spring_couple should not do thie
if (force_flag == 0) {
MPI_Allreduce(ftotal,ftotal_all,3,MPI_DOUBLE,MPI_SUM,world);