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pair_lj_cut_coul_debye.cpp
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text/x-c
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Sat, Aug 24, 17:08 (2 d)
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blob
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rLAMMPS lammps
pair_lj_cut_coul_debye.cpp
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/* ----------------------------------------------------------------------
LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
http://lammps.sandia.gov, Sandia National Laboratories
Steve Plimpton, sjplimp@sandia.gov
Copyright (2003) Sandia Corporation. Under the terms of Contract
DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
certain rights in this software. This software is distributed under
the GNU General Public License.
See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */
#include "math.h"
#include "stdlib.h"
#include "pair_lj_cut_coul_debye.h"
#include "atom.h"
#include "neigh_list.h"
#include "force.h"
#include "comm.h"
#include "error.h"
using
namespace
LAMMPS_NS
;
/* ---------------------------------------------------------------------- */
PairLJCutCoulDebye
::
PairLJCutCoulDebye
(
LAMMPS
*
lmp
)
:
PairLJCutCoulCut
(
lmp
)
{}
/* ---------------------------------------------------------------------- */
void
PairLJCutCoulDebye
::
compute
(
int
eflag
,
int
vflag
)
{
int
i
,
j
,
ii
,
jj
,
inum
,
jnum
,
itype
,
jtype
;
double
qtmp
,
xtmp
,
ytmp
,
ztmp
,
delx
,
dely
,
delz
,
evdwl
,
ecoul
,
fpair
;
double
rsq
,
r2inv
,
r6inv
,
forcecoul
,
forcelj
,
factor_coul
,
factor_lj
;
double
r
,
rinv
,
screening
;
int
*
ilist
,
*
jlist
,
*
numneigh
,
**
firstneigh
;
evdwl
=
ecoul
=
0.0
;
if
(
eflag
||
vflag
)
ev_setup
(
eflag
,
vflag
);
else
evflag
=
vflag_fdotr
=
0
;
double
**
x
=
atom
->
x
;
double
**
f
=
atom
->
f
;
double
*
q
=
atom
->
q
;
int
*
type
=
atom
->
type
;
int
nlocal
=
atom
->
nlocal
;
int
nall
=
nlocal
+
atom
->
nghost
;
double
*
special_coul
=
force
->
special_coul
;
double
*
special_lj
=
force
->
special_lj
;
int
newton_pair
=
force
->
newton_pair
;
double
qqrd2e
=
force
->
qqrd2e
;
inum
=
list
->
inum
;
ilist
=
list
->
ilist
;
numneigh
=
list
->
numneigh
;
firstneigh
=
list
->
firstneigh
;
// loop over neighbors of my atoms
for
(
ii
=
0
;
ii
<
inum
;
ii
++
)
{
i
=
ilist
[
ii
];
qtmp
=
q
[
i
];
xtmp
=
x
[
i
][
0
];
ytmp
=
x
[
i
][
1
];
ztmp
=
x
[
i
][
2
];
itype
=
type
[
i
];
jlist
=
firstneigh
[
i
];
jnum
=
numneigh
[
i
];
for
(
jj
=
0
;
jj
<
jnum
;
jj
++
)
{
j
=
jlist
[
jj
];
if
(
j
<
nall
)
factor_coul
=
factor_lj
=
1.0
;
else
{
factor_coul
=
special_coul
[
j
/
nall
];
factor_lj
=
special_lj
[
j
/
nall
];
j
%=
nall
;
}
delx
=
xtmp
-
x
[
j
][
0
];
dely
=
ytmp
-
x
[
j
][
1
];
delz
=
ztmp
-
x
[
j
][
2
];
rsq
=
delx
*
delx
+
dely
*
dely
+
delz
*
delz
;
jtype
=
type
[
j
];
if
(
rsq
<
cutsq
[
itype
][
jtype
])
{
r2inv
=
1.0
/
rsq
;
if
(
rsq
<
cut_coulsq
[
itype
][
jtype
])
{
r
=
sqrt
(
rsq
);
rinv
=
1.0
/
r
;
screening
=
exp
(
-
kappa
*
r
);
forcecoul
=
qqrd2e
*
qtmp
*
q
[
j
]
*
screening
*
(
kappa
+
rinv
);
}
else
forcecoul
=
0.0
;
if
(
rsq
<
cut_ljsq
[
itype
][
jtype
])
{
r6inv
=
r2inv
*
r2inv
*
r2inv
;
forcelj
=
r6inv
*
(
lj1
[
itype
][
jtype
]
*
r6inv
-
lj2
[
itype
][
jtype
]);
}
else
forcelj
=
0.0
;
fpair
=
(
factor_coul
*
forcecoul
+
factor_lj
*
forcelj
)
*
r2inv
;
f
[
i
][
0
]
+=
delx
*
fpair
;
f
[
i
][
1
]
+=
dely
*
fpair
;
f
[
i
][
2
]
+=
delz
*
fpair
;
if
(
newton_pair
||
j
<
nlocal
)
{
f
[
j
][
0
]
-=
delx
*
fpair
;
f
[
j
][
1
]
-=
dely
*
fpair
;
f
[
j
][
2
]
-=
delz
*
fpair
;
}
if
(
eflag
)
{
if
(
rsq
<
cut_coulsq
[
itype
][
jtype
])
ecoul
=
factor_coul
*
qqrd2e
*
qtmp
*
q
[
j
]
*
rinv
*
screening
;
else
ecoul
=
0.0
;
if
(
rsq
<
cut_ljsq
[
itype
][
jtype
])
{
evdwl
=
r6inv
*
(
lj3
[
itype
][
jtype
]
*
r6inv
-
lj4
[
itype
][
jtype
])
-
offset
[
itype
][
jtype
];
evdwl
*=
factor_lj
;
}
else
evdwl
=
0.0
;
}
if
(
evflag
)
ev_tally
(
i
,
j
,
nlocal
,
newton_pair
,
evdwl
,
ecoul
,
fpair
,
delx
,
dely
,
delz
);
}
}
}
if
(
vflag_fdotr
)
virial_compute
();
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void
PairLJCutCoulDebye
::
settings
(
int
narg
,
char
**
arg
)
{
if
(
narg
<
2
||
narg
>
3
)
error
->
all
(
"Illegal pair_style command"
);
kappa
=
force
->
numeric
(
arg
[
0
]);
cut_lj_global
=
force
->
numeric
(
arg
[
1
]);
if
(
narg
==
2
)
cut_coul_global
=
cut_lj_global
;
else
cut_coul_global
=
force
->
numeric
(
arg
[
2
]);
// reset cutoffs that were previously set from data file
if
(
allocated
)
{
int
i
,
j
;
for
(
i
=
1
;
i
<=
atom
->
ntypes
;
i
++
)
for
(
j
=
i
+
1
;
j
<=
atom
->
ntypes
;
j
++
)
if
(
setflag
[
i
][
j
]
==
1
)
{
cut_lj
[
i
][
j
]
=
cut_lj_global
;
cut_coul
[
i
][
j
]
=
cut_coul_global
;
}
}
}
/* ----------------------------------------------------------------------
proc 0 writes to restart file
------------------------------------------------------------------------- */
void
PairLJCutCoulDebye
::
write_restart_settings
(
FILE
*
fp
)
{
fwrite
(
&
cut_lj_global
,
sizeof
(
double
),
1
,
fp
);
fwrite
(
&
cut_coul_global
,
sizeof
(
double
),
1
,
fp
);
fwrite
(
&
kappa
,
sizeof
(
double
),
1
,
fp
);
fwrite
(
&
offset_flag
,
sizeof
(
int
),
1
,
fp
);
fwrite
(
&
mix_flag
,
sizeof
(
int
),
1
,
fp
);
}
/* ----------------------------------------------------------------------
proc 0 reads from restart file, bcasts
------------------------------------------------------------------------- */
void
PairLJCutCoulDebye
::
read_restart_settings
(
FILE
*
fp
)
{
if
(
comm
->
me
==
0
)
{
fread
(
&
cut_lj_global
,
sizeof
(
double
),
1
,
fp
);
fread
(
&
cut_coul_global
,
sizeof
(
double
),
1
,
fp
);
fread
(
&
kappa
,
sizeof
(
double
),
1
,
fp
);
fread
(
&
offset_flag
,
sizeof
(
int
),
1
,
fp
);
fread
(
&
mix_flag
,
sizeof
(
int
),
1
,
fp
);
}
MPI_Bcast
(
&
cut_lj_global
,
1
,
MPI_DOUBLE
,
0
,
world
);
MPI_Bcast
(
&
cut_coul_global
,
1
,
MPI_DOUBLE
,
0
,
world
);
MPI_Bcast
(
&
kappa
,
1
,
MPI_DOUBLE
,
0
,
world
);
MPI_Bcast
(
&
offset_flag
,
1
,
MPI_INT
,
0
,
world
);
MPI_Bcast
(
&
mix_flag
,
1
,
MPI_INT
,
0
,
world
);
}
/* ---------------------------------------------------------------------- */
double
PairLJCutCoulDebye
::
single
(
int
i
,
int
j
,
int
itype
,
int
jtype
,
double
rsq
,
double
factor_coul
,
double
factor_lj
,
double
&
fforce
)
{
double
r2inv
,
r6inv
,
r
,
rinv
,
screening
,
forcecoul
,
forcelj
,
phicoul
,
philj
;
r2inv
=
1.0
/
rsq
;
if
(
rsq
<
cut_coulsq
[
itype
][
jtype
])
{
r
=
sqrt
(
rsq
);
rinv
=
1.0
/
r
;
screening
=
exp
(
-
kappa
*
r
);
forcecoul
=
force
->
qqrd2e
*
atom
->
q
[
i
]
*
atom
->
q
[
j
]
*
screening
*
(
kappa
+
rinv
);
}
else
forcecoul
=
0.0
;
if
(
rsq
<
cut_ljsq
[
itype
][
jtype
])
{
r6inv
=
r2inv
*
r2inv
*
r2inv
;
forcelj
=
r6inv
*
(
lj1
[
itype
][
jtype
]
*
r6inv
-
lj2
[
itype
][
jtype
]);
}
else
forcelj
=
0.0
;
fforce
=
(
factor_coul
*
forcecoul
+
factor_lj
*
forcelj
)
*
r2inv
;
double
eng
=
0.0
;
if
(
rsq
<
cut_coulsq
[
itype
][
jtype
])
{
phicoul
=
force
->
qqrd2e
*
atom
->
q
[
i
]
*
atom
->
q
[
j
]
*
rinv
*
screening
;
eng
+=
factor_coul
*
phicoul
;
}
if
(
rsq
<
cut_ljsq
[
itype
][
jtype
])
{
philj
=
r6inv
*
(
lj3
[
itype
][
jtype
]
*
r6inv
-
lj4
[
itype
][
jtype
])
-
offset
[
itype
][
jtype
];
eng
+=
factor_lj
*
philj
;
}
return
eng
;
}
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