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pair_lj_cut_coul_long_tip4p.cpp
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rLAMMPS lammps
pair_lj_cut_coul_long_tip4p.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.
------------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
Contributing authors: Amalie Frischknecht and Ahmed Ismail (SNL)
------------------------------------------------------------------------- */
#include "math.h"
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "pair_lj_cut_coul_long_tip4p.h"
#include "angle.h"
#include "atom.h"
#include "bond.h"
#include "comm.h"
#include "domain.h"
#include "force.h"
#include "kspace.h"
#include "update.h"
#include "respa.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "neigh_request.h"
#include "memory.h"
#include "error.h"
using
namespace
LAMMPS_NS
;
#define EWALD_F 1.12837917
#define EWALD_P 0.3275911
#define A1 0.254829592
#define A2 -0.284496736
#define A3 1.421413741
#define A4 -1.453152027
#define A5 1.061405429
/* ---------------------------------------------------------------------- */
PairLJCutCoulLongTIP4P
::
PairLJCutCoulLongTIP4P
(
LAMMPS
*
lmp
)
:
PairLJCutCoulLong
(
lmp
)
{
single_enable
=
0
;
respa_enable
=
0
;
// TIP4P cannot compute virial as F dot r
// due to find_M() finding bonded H atoms which are not near O atom
no_virial_fdotr_compute
=
1
;
}
/* ---------------------------------------------------------------------- */
void
PairLJCutCoulLongTIP4P
::
compute
(
int
eflag
,
int
vflag
)
{
int
i
,
j
,
ii
,
jj
,
inum
,
jnum
,
itype
,
jtype
,
itable
;
int
n
,
vlist
[
6
];
int
iH1
,
iH2
,
jH1
,
jH2
;
double
qtmp
,
xtmp
,
ytmp
,
ztmp
,
delx
,
dely
,
delz
,
evdwl
,
ecoul
;
double
fraction
,
table
;
double
delxOM
,
delyOM
,
delzOM
;
double
r
,
r2inv
,
r6inv
,
forcecoul
,
forcelj
,
cforce
;
double
factor_coul
,
factor_lj
;
double
grij
,
expm2
,
prefactor
,
t
,
erfc
,
ddotf
;
double
xiM
[
3
],
xjM
[
3
],
fO
[
3
],
fH
[
3
],
fd
[
3
],
f1
[
3
],
v
[
6
],
xH1
[
3
],
xH2
[
3
];
double
*
x1
,
*
x2
;
int
*
ilist
,
*
jlist
,
*
numneigh
,
**
firstneigh
;
double
rsq
;
evdwl
=
ecoul
=
0.0
;
if
(
eflag
||
vflag
)
ev_setup
(
eflag
,
vflag
);
else
evflag
=
vflag_fdotr
=
0
;
double
**
f
=
atom
->
f
;
double
**
x
=
atom
->
x
;
double
*
q
=
atom
->
q
;
int
*
type
=
atom
->
type
;
int
nlocal
=
atom
->
nlocal
;
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
];
if
(
itype
==
typeO
)
{
find_M
(
i
,
iH1
,
iH2
,
xiM
);
x1
=
xiM
;
}
else
x1
=
x
[
i
];
jlist
=
firstneigh
[
i
];
jnum
=
numneigh
[
i
];
for
(
jj
=
0
;
jj
<
jnum
;
jj
++
)
{
j
=
jlist
[
jj
];
factor_lj
=
special_lj
[
sbmask
(
j
)];
factor_coul
=
special_coul
[
sbmask
(
j
)];
j
&=
NEIGHMASK
;
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_ljsq
[
itype
][
jtype
])
{
r6inv
=
r2inv
*
r2inv
*
r2inv
;
forcelj
=
r6inv
*
(
lj1
[
itype
][
jtype
]
*
r6inv
-
lj2
[
itype
][
jtype
]);
forcelj
*=
factor_lj
*
r2inv
;
f
[
i
][
0
]
+=
delx
*
forcelj
;
f
[
i
][
1
]
+=
dely
*
forcelj
;
f
[
i
][
2
]
+=
delz
*
forcelj
;
f
[
j
][
0
]
-=
delx
*
forcelj
;
f
[
j
][
1
]
-=
dely
*
forcelj
;
f
[
j
][
2
]
-=
delz
*
forcelj
;
if
(
eflag
)
{
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
,
0.0
,
forcelj
,
delx
,
dely
,
delz
);
}
// adjust rsq and delxyz for off-site O charge(s)
if
(
itype
==
typeO
||
jtype
==
typeO
)
{
if
(
jtype
==
typeO
)
{
find_M
(
j
,
jH1
,
jH2
,
xjM
);
x2
=
xjM
;
}
else
x2
=
x
[
j
];
delx
=
x1
[
0
]
-
x2
[
0
];
dely
=
x1
[
1
]
-
x2
[
1
];
delz
=
x1
[
2
]
-
x2
[
2
];
rsq
=
delx
*
delx
+
dely
*
dely
+
delz
*
delz
;
}
// test current rsq against cutoff and compute Coulombic force
if
(
rsq
<
cut_coulsq
)
{
r2inv
=
1
/
rsq
;
if
(
!
ncoultablebits
||
rsq
<=
tabinnersq
)
{
r
=
sqrt
(
rsq
);
grij
=
g_ewald
*
r
;
expm2
=
exp
(
-
grij
*
grij
);
t
=
1.0
/
(
1.0
+
EWALD_P
*
grij
);
erfc
=
t
*
(
A1
+
t
*
(
A2
+
t
*
(
A3
+
t
*
(
A4
+
t
*
A5
))))
*
expm2
;
prefactor
=
qqrd2e
*
qtmp
*
q
[
j
]
/
r
;
forcecoul
=
prefactor
*
(
erfc
+
EWALD_F
*
grij
*
expm2
);
if
(
factor_coul
<
1.0
)
{
forcecoul
-=
(
1.0
-
factor_coul
)
*
prefactor
;
}
}
else
{
union_int_float_t
rsq_lookup
;
rsq_lookup
.
f
=
rsq
;
itable
=
rsq_lookup
.
i
&
ncoulmask
;
itable
>>=
ncoulshiftbits
;
fraction
=
(
rsq_lookup
.
f
-
rtable
[
itable
])
*
drtable
[
itable
];
table
=
ftable
[
itable
]
+
fraction
*
dftable
[
itable
];
forcecoul
=
qtmp
*
q
[
j
]
*
table
;
if
(
factor_coul
<
1.0
)
{
table
=
ctable
[
itable
]
+
fraction
*
dctable
[
itable
];
prefactor
=
qtmp
*
q
[
j
]
*
table
;
forcecoul
-=
(
1.0
-
factor_coul
)
*
prefactor
;
}
}
cforce
=
forcecoul
*
r2inv
;
// if i,j are not O atoms, force is applied directly
// if i or j are O atoms, force is on fictitious atom & partitioned
// force partitioning due to Feenstra, J Comp Chem, 20, 786 (1999)
// f_f = fictitious force, fO = f_f (1 - 2 alpha), fH = alpha f_f
// preserves total force and torque on water molecule
// virial = sum(r x F) where each water's atoms are near xi and xj
// vlist stores 2,4,6 atoms whose forces contribute to virial
n
=
0
;
if
(
itype
!=
typeO
)
{
f
[
i
][
0
]
+=
delx
*
cforce
;
f
[
i
][
1
]
+=
dely
*
cforce
;
f
[
i
][
2
]
+=
delz
*
cforce
;
if
(
vflag
)
{
v
[
0
]
=
x
[
i
][
0
]
*
delx
*
cforce
;
v
[
1
]
=
x
[
i
][
1
]
*
dely
*
cforce
;
v
[
2
]
=
x
[
i
][
2
]
*
delz
*
cforce
;
v
[
3
]
=
x
[
i
][
0
]
*
dely
*
cforce
;
v
[
4
]
=
x
[
i
][
0
]
*
delz
*
cforce
;
v
[
5
]
=
x
[
i
][
1
]
*
delz
*
cforce
;
vlist
[
n
++
]
=
i
;
}
}
else
{
fd
[
0
]
=
delx
*
cforce
;
fd
[
1
]
=
dely
*
cforce
;
fd
[
2
]
=
delz
*
cforce
;
delxOM
=
x
[
i
][
0
]
-
x1
[
0
];
delyOM
=
x
[
i
][
1
]
-
x1
[
1
];
delzOM
=
x
[
i
][
2
]
-
x1
[
2
];
ddotf
=
(
delxOM
*
fd
[
0
]
+
delyOM
*
fd
[
1
]
+
delzOM
*
fd
[
2
])
/
(
qdist
*
qdist
);
f1
[
0
]
=
ddotf
*
delxOM
;
f1
[
1
]
=
ddotf
*
delyOM
;
f1
[
2
]
=
ddotf
*
delzOM
;
fO
[
0
]
=
fd
[
0
]
-
alpha
*
(
fd
[
0
]
-
f1
[
0
]);
fO
[
1
]
=
fd
[
1
]
-
alpha
*
(
fd
[
1
]
-
f1
[
1
]);
fO
[
2
]
=
fd
[
2
]
-
alpha
*
(
fd
[
2
]
-
f1
[
2
]);
fH
[
0
]
=
0.5
*
alpha
*
(
fd
[
0
]
-
f1
[
0
]);
fH
[
1
]
=
0.5
*
alpha
*
(
fd
[
1
]
-
f1
[
1
]);
fH
[
2
]
=
0.5
*
alpha
*
(
fd
[
2
]
-
f1
[
2
]);
f
[
i
][
0
]
+=
fO
[
0
];
f
[
i
][
1
]
+=
fO
[
1
];
f
[
i
][
2
]
+=
fO
[
2
];
f
[
iH1
][
0
]
+=
fH
[
0
];
f
[
iH1
][
1
]
+=
fH
[
1
];
f
[
iH1
][
2
]
+=
fH
[
2
];
f
[
iH2
][
0
]
+=
fH
[
0
];
f
[
iH2
][
1
]
+=
fH
[
1
];
f
[
iH2
][
2
]
+=
fH
[
2
];
if
(
vflag
)
{
domain
->
closest_image
(
x
[
i
],
x
[
iH1
],
xH1
);
domain
->
closest_image
(
x
[
i
],
x
[
iH2
],
xH2
);
v
[
0
]
=
x
[
i
][
0
]
*
fO
[
0
]
+
xH1
[
0
]
*
fH
[
0
]
+
xH2
[
0
]
*
fH
[
0
];
v
[
1
]
=
x
[
i
][
1
]
*
fO
[
1
]
+
xH1
[
1
]
*
fH
[
1
]
+
xH2
[
1
]
*
fH
[
1
];
v
[
2
]
=
x
[
i
][
2
]
*
fO
[
2
]
+
xH1
[
2
]
*
fH
[
2
]
+
xH2
[
2
]
*
fH
[
2
];
v
[
3
]
=
x
[
i
][
0
]
*
fO
[
1
]
+
xH1
[
0
]
*
fH
[
1
]
+
xH2
[
0
]
*
fH
[
1
];
v
[
4
]
=
x
[
i
][
0
]
*
fO
[
2
]
+
xH1
[
0
]
*
fH
[
2
]
+
xH2
[
0
]
*
fH
[
2
];
v
[
5
]
=
x
[
i
][
1
]
*
fO
[
2
]
+
xH1
[
1
]
*
fH
[
2
]
+
xH2
[
1
]
*
fH
[
2
];
vlist
[
n
++
]
=
i
;
vlist
[
n
++
]
=
iH1
;
vlist
[
n
++
]
=
iH2
;
}
}
if
(
jtype
!=
typeO
)
{
f
[
j
][
0
]
-=
delx
*
cforce
;
f
[
j
][
1
]
-=
dely
*
cforce
;
f
[
j
][
2
]
-=
delz
*
cforce
;
if
(
vflag
)
{
v
[
0
]
-=
x
[
j
][
0
]
*
delx
*
cforce
;
v
[
1
]
-=
x
[
j
][
1
]
*
dely
*
cforce
;
v
[
2
]
-=
x
[
j
][
2
]
*
delz
*
cforce
;
v
[
3
]
-=
x
[
j
][
0
]
*
dely
*
cforce
;
v
[
4
]
-=
x
[
j
][
0
]
*
delz
*
cforce
;
v
[
5
]
-=
x
[
j
][
1
]
*
delz
*
cforce
;
vlist
[
n
++
]
=
j
;
}
}
else
{
fd
[
0
]
=
-
delx
*
cforce
;
fd
[
1
]
=
-
dely
*
cforce
;
fd
[
2
]
=
-
delz
*
cforce
;
delxOM
=
x
[
j
][
0
]
-
x2
[
0
];
delyOM
=
x
[
j
][
1
]
-
x2
[
1
];
delzOM
=
x
[
j
][
2
]
-
x2
[
2
];
ddotf
=
(
delxOM
*
fd
[
0
]
+
delyOM
*
fd
[
1
]
+
delzOM
*
fd
[
2
])
/
(
qdist
*
qdist
);
f1
[
0
]
=
ddotf
*
delxOM
;
f1
[
1
]
=
ddotf
*
delyOM
;
f1
[
2
]
=
ddotf
*
delzOM
;
fO
[
0
]
=
fd
[
0
]
-
alpha
*
(
fd
[
0
]
-
f1
[
0
]);
fO
[
1
]
=
fd
[
1
]
-
alpha
*
(
fd
[
1
]
-
f1
[
1
]);
fO
[
2
]
=
fd
[
2
]
-
alpha
*
(
fd
[
2
]
-
f1
[
2
]);
fH
[
0
]
=
0.5
*
alpha
*
(
fd
[
0
]
-
f1
[
0
]);
fH
[
1
]
=
0.5
*
alpha
*
(
fd
[
1
]
-
f1
[
1
]);
fH
[
2
]
=
0.5
*
alpha
*
(
fd
[
2
]
-
f1
[
2
]);
f
[
j
][
0
]
+=
fO
[
0
];
f
[
j
][
1
]
+=
fO
[
1
];
f
[
j
][
2
]
+=
fO
[
2
];
f
[
jH1
][
0
]
+=
fH
[
0
];
f
[
jH1
][
1
]
+=
fH
[
1
];
f
[
jH1
][
2
]
+=
fH
[
2
];
f
[
jH2
][
0
]
+=
fH
[
0
];
f
[
jH2
][
1
]
+=
fH
[
1
];
f
[
jH2
][
2
]
+=
fH
[
2
];
if
(
vflag
)
{
domain
->
closest_image
(
x
[
j
],
x
[
jH1
],
xH1
);
domain
->
closest_image
(
x
[
j
],
x
[
jH2
],
xH2
);
v
[
0
]
+=
x
[
j
][
0
]
*
fO
[
0
]
+
xH1
[
0
]
*
fH
[
0
]
+
xH2
[
0
]
*
fH
[
0
];
v
[
1
]
+=
x
[
j
][
1
]
*
fO
[
1
]
+
xH1
[
1
]
*
fH
[
1
]
+
xH2
[
1
]
*
fH
[
1
];
v
[
2
]
+=
x
[
j
][
2
]
*
fO
[
2
]
+
xH1
[
2
]
*
fH
[
2
]
+
xH2
[
2
]
*
fH
[
2
];
v
[
3
]
+=
x
[
j
][
0
]
*
fO
[
1
]
+
xH1
[
0
]
*
fH
[
1
]
+
xH2
[
0
]
*
fH
[
1
];
v
[
4
]
+=
x
[
j
][
0
]
*
fO
[
2
]
+
xH1
[
0
]
*
fH
[
2
]
+
xH2
[
0
]
*
fH
[
2
];
v
[
5
]
+=
x
[
j
][
1
]
*
fO
[
2
]
+
xH1
[
1
]
*
fH
[
2
]
+
xH2
[
1
]
*
fH
[
2
];
vlist
[
n
++
]
=
j
;
vlist
[
n
++
]
=
jH1
;
vlist
[
n
++
]
=
jH2
;
}
}
if
(
eflag
)
{
if
(
!
ncoultablebits
||
rsq
<=
tabinnersq
)
ecoul
=
prefactor
*
erfc
;
else
{
table
=
etable
[
itable
]
+
fraction
*
detable
[
itable
];
ecoul
=
qtmp
*
q
[
j
]
*
table
;
}
if
(
factor_coul
<
1.0
)
ecoul
-=
(
1.0
-
factor_coul
)
*
prefactor
;
}
else
ecoul
=
0.0
;
if
(
evflag
)
ev_tally_list
(
n
,
vlist
,
ecoul
,
v
);
}
}
}
}
}
/* ----------------------------------------------------------------------
global settings
------------------------------------------------------------------------- */
void
PairLJCutCoulLongTIP4P
::
settings
(
int
narg
,
char
**
arg
)
{
if
(
narg
<
6
||
narg
>
7
)
error
->
all
(
FLERR
,
"Illegal pair_style command"
);
typeO
=
force
->
inumeric
(
arg
[
0
]);
typeH
=
force
->
inumeric
(
arg
[
1
]);
typeB
=
force
->
inumeric
(
arg
[
2
]);
typeA
=
force
->
inumeric
(
arg
[
3
]);
qdist
=
force
->
numeric
(
arg
[
4
]);
cut_lj_global
=
force
->
numeric
(
arg
[
5
]);
if
(
narg
==
6
)
cut_coul
=
cut_lj_global
;
else
cut_coul
=
force
->
numeric
(
arg
[
6
]);
// reset cutoffs that have been explicitly set
if
(
allocated
)
{
int
i
,
j
;
for
(
i
=
1
;
i
<=
atom
->
ntypes
;
i
++
)
for
(
j
=
i
+
1
;
j
<=
atom
->
ntypes
;
j
++
)
if
(
setflag
[
i
][
j
])
cut_lj
[
i
][
j
]
=
cut_lj_global
;
}
}
/* ----------------------------------------------------------------------
init specific to this pair style
------------------------------------------------------------------------- */
void
PairLJCutCoulLongTIP4P
::
init_style
()
{
if
(
atom
->
tag_enable
==
0
)
error
->
all
(
FLERR
,
"Pair style lj/cut/coul/long/tip4p requires atom IDs"
);
if
(
!
force
->
newton_pair
)
error
->
all
(
FLERR
,
"Pair style lj/cut/coul/long/tip4p requires newton pair on"
);
if
(
!
atom
->
q_flag
)
error
->
all
(
FLERR
,
"Pair style lj/cut/coul/long/tip4p requires atom attribute q"
);
if
(
(
strcmp
(
force
->
kspace_style
,
"pppm/tip4p"
)
!=
0
)
&&
(
strcmp
(
force
->
kspace_style
,
"pppm/tip4p/proxy"
)
!=
0
)
)
error
->
all
(
FLERR
,
"Pair style is incompatible with KSpace style"
);
if
(
force
->
bond
==
NULL
)
error
->
all
(
FLERR
,
"Must use a bond style with TIP4P potential"
);
if
(
force
->
angle
==
NULL
)
error
->
all
(
FLERR
,
"Must use an angle style with TIP4P potential"
);
PairLJCutCoulLong
::
init_style
();
// set alpha parameter
double
theta
=
force
->
angle
->
equilibrium_angle
(
typeA
);
double
blen
=
force
->
bond
->
equilibrium_distance
(
typeB
);
alpha
=
qdist
/
(
cos
(
0.5
*
theta
)
*
blen
);
}
/* ----------------------------------------------------------------------
proc 0 writes to restart file
------------------------------------------------------------------------- */
void
PairLJCutCoulLongTIP4P
::
write_restart_settings
(
FILE
*
fp
)
{
fwrite
(
&
typeO
,
sizeof
(
int
),
1
,
fp
);
fwrite
(
&
typeH
,
sizeof
(
int
),
1
,
fp
);
fwrite
(
&
typeB
,
sizeof
(
int
),
1
,
fp
);
fwrite
(
&
typeA
,
sizeof
(
int
),
1
,
fp
);
fwrite
(
&
qdist
,
sizeof
(
double
),
1
,
fp
);
fwrite
(
&
cut_lj_global
,
sizeof
(
double
),
1
,
fp
);
fwrite
(
&
cut_coul
,
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
PairLJCutCoulLongTIP4P
::
read_restart_settings
(
FILE
*
fp
)
{
if
(
comm
->
me
==
0
)
{
fread
(
&
typeO
,
sizeof
(
int
),
1
,
fp
);
fread
(
&
typeH
,
sizeof
(
int
),
1
,
fp
);
fread
(
&
typeB
,
sizeof
(
int
),
1
,
fp
);
fread
(
&
typeA
,
sizeof
(
int
),
1
,
fp
);
fread
(
&
qdist
,
sizeof
(
double
),
1
,
fp
);
fread
(
&
cut_lj_global
,
sizeof
(
double
),
1
,
fp
);
fread
(
&
cut_coul
,
sizeof
(
double
),
1
,
fp
);
fread
(
&
offset_flag
,
sizeof
(
int
),
1
,
fp
);
fread
(
&
mix_flag
,
sizeof
(
int
),
1
,
fp
);
}
MPI_Bcast
(
&
typeO
,
1
,
MPI_INT
,
0
,
world
);
MPI_Bcast
(
&
typeH
,
1
,
MPI_INT
,
0
,
world
);
MPI_Bcast
(
&
typeB
,
1
,
MPI_INT
,
0
,
world
);
MPI_Bcast
(
&
typeA
,
1
,
MPI_INT
,
0
,
world
);
MPI_Bcast
(
&
qdist
,
1
,
MPI_DOUBLE
,
0
,
world
);
MPI_Bcast
(
&
cut_lj_global
,
1
,
MPI_DOUBLE
,
0
,
world
);
MPI_Bcast
(
&
cut_coul
,
1
,
MPI_DOUBLE
,
0
,
world
);
MPI_Bcast
(
&
offset_flag
,
1
,
MPI_INT
,
0
,
world
);
MPI_Bcast
(
&
mix_flag
,
1
,
MPI_INT
,
0
,
world
);
}
/* ----------------------------------------------------------------------
find 2 H atoms bonded to O atom i
compute position xM of fictitious charge site for O atom
also return local indices iH1,iH2 of H atoms
------------------------------------------------------------------------- */
void
PairLJCutCoulLongTIP4P
::
find_M
(
int
i
,
int
&
iH1
,
int
&
iH2
,
double
*
xM
)
{
// test that O is correctly bonded to 2 succesive H atoms
iH1
=
atom
->
map
(
atom
->
tag
[
i
]
+
1
);
iH2
=
atom
->
map
(
atom
->
tag
[
i
]
+
2
);
if
(
iH1
==
-
1
||
iH2
==
-
1
)
error
->
one
(
FLERR
,
"TIP4P hydrogen is missing"
);
if
(
atom
->
type
[
iH1
]
!=
typeH
||
atom
->
type
[
iH2
]
!=
typeH
)
error
->
one
(
FLERR
,
"TIP4P hydrogen has incorrect atom type"
);
double
**
x
=
atom
->
x
;
double
delx1
=
x
[
iH1
][
0
]
-
x
[
i
][
0
];
double
dely1
=
x
[
iH1
][
1
]
-
x
[
i
][
1
];
double
delz1
=
x
[
iH1
][
2
]
-
x
[
i
][
2
];
domain
->
minimum_image
(
delx1
,
dely1
,
delz1
);
double
delx2
=
x
[
iH2
][
0
]
-
x
[
i
][
0
];
double
dely2
=
x
[
iH2
][
1
]
-
x
[
i
][
1
];
double
delz2
=
x
[
iH2
][
2
]
-
x
[
i
][
2
];
domain
->
minimum_image
(
delx2
,
dely2
,
delz2
);
xM
[
0
]
=
x
[
i
][
0
]
+
alpha
*
0.5
*
(
delx1
+
delx2
);
xM
[
1
]
=
x
[
i
][
1
]
+
alpha
*
0.5
*
(
dely1
+
dely2
);
xM
[
2
]
=
x
[
i
][
2
]
+
alpha
*
0.5
*
(
delz1
+
delz2
);
}
/* ---------------------------------------------------------------------- */
void
*
PairLJCutCoulLongTIP4P
::
extract
(
char
*
str
,
int
&
dim
)
{
dim
=
0
;
if
(
strcmp
(
str
,
"qdist"
)
==
0
)
return
(
void
*
)
&
qdist
;
if
(
strcmp
(
str
,
"typeO"
)
==
0
)
return
(
void
*
)
&
typeO
;
if
(
strcmp
(
str
,
"typeH"
)
==
0
)
return
(
void
*
)
&
typeH
;
if
(
strcmp
(
str
,
"typeA"
)
==
0
)
return
(
void
*
)
&
typeA
;
if
(
strcmp
(
str
,
"typeB"
)
==
0
)
return
(
void
*
)
&
typeB
;
if
(
strcmp
(
str
,
"cut_coul"
)
==
0
)
return
(
void
*
)
&
cut_coul
;
return
NULL
;
}
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