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pair_lj_charmm_coul_long_opt.cpp
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Created
Wed, Feb 19, 00:11
Size
10 KB
Mime Type
text/x-c++
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Fri, Feb 21, 00:11 (1 d, 23 h)
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blob
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rLAMMPS lammps
pair_lj_charmm_coul_long_opt.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:
James Fischer, High Performance Technologies, Inc.
David Richie, Stone Ridge Technology
Vincent Natoli, Stone Ridge Technology
------------------------------------------------------------------------- */
#include "math.h"
#include "stdlib.h"
#include "pair_lj_charmm_coul_long_opt.h"
#include "atom.h"
#include "force.h"
#include "neigh_list.h"
using
namespace
LAMMPS_NS
;
#define EWALD_F 1.12837917
#define EWALD_P 0.3275911
#define EWALD_A1 0.254829592
#define EWALD_A2 -0.284496736
#define EWALD_A3 1.421413741
#define EWALD_A4 -1.453152027
#define EWALD_A5 1.061405429
/* ---------------------------------------------------------------------- */
PairLJCharmmCoulLongOpt
::
PairLJCharmmCoulLongOpt
(
LAMMPS
*
lmp
)
:
PairLJCharmmCoulLong
(
lmp
)
{}
/* ---------------------------------------------------------------------- */
void
PairLJCharmmCoulLongOpt
::
compute
(
int
eflag
,
int
vflag
)
{
if
(
eflag
||
vflag
)
ev_setup
(
eflag
,
vflag
);
else
evflag
=
vflag_fdotr
=
0
;
if
(
evflag
)
{
if
(
eflag
)
{
if
(
force
->
newton_pair
)
return
eval
<
1
,
1
,
1
>
();
else
return
eval
<
1
,
1
,
0
>
();
}
else
{
if
(
force
->
newton_pair
)
return
eval
<
1
,
0
,
1
>
();
else
return
eval
<
1
,
0
,
0
>
();
}
}
else
{
if
(
force
->
newton_pair
)
return
eval
<
0
,
0
,
1
>
();
else
return
eval
<
0
,
0
,
0
>
();
}
}
/* ---------------------------------------------------------------------- */
template
<
int
EVFLAG
,
int
EFLAG
,
int
NEWTON_PAIR
>
void
PairLJCharmmCoulLongOpt
::
eval
()
{
typedef
struct
{
double
x
,
y
,
z
;
}
vec3_t
;
typedef
struct
{
double
cutsq
,
lj1
,
lj2
,
lj3
,
lj4
,
offset
;
double
_pad
[
2
];
}
fast_alpha_t
;
int
i
,
j
,
ii
,
jj
,
inum
,
jnum
,
itype
,
jtype
,
itable
,
sbindex
;
double
fraction
,
table
;
double
r
,
r2inv
,
r6inv
,
forcecoul
,
forcelj
,
factor_coul
,
factor_lj
;
double
grij
,
expm2
,
prefactor
,
t
,
erfc
;
double
philj
,
switch1
,
switch2
;
double
rsq
;
double
evdwl
=
0.0
;
double
ecoul
=
0.0
;
double
**
_noalias
x
=
atom
->
x
;
double
**
_noalias
f
=
atom
->
f
;
double
*
_noalias
q
=
atom
->
q
;
int
*
_noalias
type
=
atom
->
type
;
int
nlocal
=
atom
->
nlocal
;
double
*
_noalias
special_coul
=
force
->
special_coul
;
double
*
_noalias
special_lj
=
force
->
special_lj
;
double
qqrd2e
=
force
->
qqrd2e
;
inum
=
list
->
inum
;
int
*
_noalias
ilist
=
list
->
ilist
;
int
**
_noalias
firstneigh
=
list
->
firstneigh
;
int
*
_noalias
numneigh
=
list
->
numneigh
;
vec3_t
*
_noalias
xx
=
(
vec3_t
*
)
x
[
0
];
vec3_t
*
_noalias
ff
=
(
vec3_t
*
)
f
[
0
];
int
ntypes
=
atom
->
ntypes
;
int
ntypes2
=
ntypes
*
ntypes
;
double
tmp_coef1
=
1.0
/
denom_lj
;
double
tmp_coef2
=
cut_ljsq
-
3.0
*
cut_lj_innersq
;
fast_alpha_t
*
_noalias
fast_alpha
=
(
fast_alpha_t
*
)
malloc
(
ntypes2
*
sizeof
(
fast_alpha_t
));
for
(
i
=
0
;
i
<
ntypes
;
i
++
)
for
(
j
=
0
;
j
<
ntypes
;
j
++
)
{
fast_alpha_t
&
a
=
fast_alpha
[
i
*
ntypes
+
j
];
a
.
cutsq
=
cutsq
[
i
+
1
][
j
+
1
];
a
.
lj1
=
lj1
[
i
+
1
][
j
+
1
];
a
.
lj2
=
lj2
[
i
+
1
][
j
+
1
];
a
.
lj3
=
lj3
[
i
+
1
][
j
+
1
];
a
.
lj4
=
lj4
[
i
+
1
][
j
+
1
];
}
fast_alpha_t
*
_noalias
tabsix
=
fast_alpha
;
// loop over neighbors of my atoms
for
(
ii
=
0
;
ii
<
inum
;
ii
++
)
{
i
=
ilist
[
ii
];
double
qtmp
=
q
[
i
];
double
xtmp
=
xx
[
i
].
x
;
double
ytmp
=
xx
[
i
].
y
;
double
ztmp
=
xx
[
i
].
z
;
itype
=
type
[
i
]
-
1
;
int
*
_noalias
jlist
=
firstneigh
[
i
];
jnum
=
numneigh
[
i
];
double
tmpfx
=
0.0
;
double
tmpfy
=
0.0
;
double
tmpfz
=
0.0
;
fast_alpha_t
*
_noalias
tabsixi
=
(
fast_alpha_t
*
)
&
tabsix
[
itype
*
ntypes
];
for
(
jj
=
0
;
jj
<
jnum
;
jj
++
)
{
j
=
jlist
[
jj
];
sbindex
=
sbmask
(
j
);
if
(
sbindex
==
0
)
{
double
delx
=
xtmp
-
xx
[
j
].
x
;
double
dely
=
ytmp
-
xx
[
j
].
y
;
double
delz
=
ztmp
-
xx
[
j
].
z
;
rsq
=
delx
*
delx
+
dely
*
dely
+
delz
*
delz
;
double
tmp_coef3
=
qtmp
*
q
[
j
];
if
(
rsq
<
cut_bothsq
)
{
r2inv
=
1.0
/
rsq
;
forcecoul
=
0.0
;
if
(
rsq
<
cut_coulsq
)
{
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
*
(
EWALD_A1
+
t
*
(
EWALD_A2
+
t
*
(
EWALD_A3
+
t
*
(
EWALD_A4
+
t
*
EWALD_A5
))))
*
expm2
;
prefactor
=
qqrd2e
*
tmp_coef3
/
r
;
forcecoul
=
prefactor
*
(
erfc
+
EWALD_F
*
grij
*
expm2
);
}
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
=
tmp_coef3
*
table
;
}
}
forcelj
=
0.0
;
if
(
rsq
<
cut_ljsq
)
{
r6inv
=
r2inv
*
r2inv
*
r2inv
;
jtype
=
type
[
j
]
-
1
;
fast_alpha_t
&
a
=
tabsixi
[
jtype
];
forcelj
=
r6inv
*
(
a
.
lj1
*
r6inv
-
a
.
lj2
);
if
(
rsq
>
cut_lj_innersq
)
{
switch1
=
(
cut_ljsq
-
rsq
)
*
(
cut_ljsq
-
rsq
)
*
(
tmp_coef2
+
2.0
*
rsq
)
*
tmp_coef1
;
switch2
=
12.0
*
rsq
*
(
cut_ljsq
-
rsq
)
*
(
rsq
-
cut_lj_innersq
)
*
tmp_coef1
;
philj
=
r6inv
*
(
a
.
lj3
*
r6inv
-
a
.
lj4
);
forcelj
=
forcelj
*
switch1
+
philj
*
switch2
;
}
}
double
fpair
=
(
forcecoul
+
forcelj
)
*
r2inv
;
tmpfx
+=
delx
*
fpair
;
tmpfy
+=
dely
*
fpair
;
tmpfz
+=
delz
*
fpair
;
if
(
NEWTON_PAIR
||
j
<
nlocal
)
{
ff
[
j
].
x
-=
delx
*
fpair
;
ff
[
j
].
y
-=
dely
*
fpair
;
ff
[
j
].
z
-=
delz
*
fpair
;
}
if
(
EFLAG
)
{
if
(
rsq
<
cut_coulsq
)
{
if
(
!
ncoultablebits
||
rsq
<=
tabinnersq
)
ecoul
=
prefactor
*
erfc
;
else
{
table
=
etable
[
itable
]
+
fraction
*
detable
[
itable
];
ecoul
=
tmp_coef3
*
table
;
}
}
else
ecoul
=
0.0
;
if
(
rsq
<
cut_ljsq
)
{
fast_alpha_t
&
a
=
tabsixi
[
jtype
];
evdwl
=
r6inv
*
(
a
.
lj3
*
r6inv
-
a
.
lj4
);
if
(
rsq
>
cut_lj_innersq
)
{
switch1
=
(
cut_ljsq
-
rsq
)
*
(
cut_ljsq
-
rsq
)
*
(
tmp_coef2
+
2.0
*
rsq
)
*
tmp_coef1
;
evdwl
*=
switch1
;
}
}
else
evdwl
=
0.0
;
}
if
(
EVFLAG
)
ev_tally
(
i
,
j
,
nlocal
,
NEWTON_PAIR
,
evdwl
,
ecoul
,
fpair
,
delx
,
dely
,
delz
);
}
}
else
{
factor_lj
=
special_lj
[
sbindex
];
factor_coul
=
special_coul
[
sbindex
];
j
&=
NEIGHMASK
;
double
delx
=
xtmp
-
xx
[
j
].
x
;
double
dely
=
ytmp
-
xx
[
j
].
y
;
double
delz
=
ztmp
-
xx
[
j
].
z
;
rsq
=
delx
*
delx
+
dely
*
dely
+
delz
*
delz
;
double
tmp_coef3
=
qtmp
*
q
[
j
];
if
(
rsq
<
cut_bothsq
)
{
r2inv
=
1.0
/
rsq
;
forcecoul
=
0.0
;
if
(
rsq
<
cut_coulsq
)
{
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
*
(
EWALD_A1
+
t
*
(
EWALD_A2
+
t
*
(
EWALD_A3
+
t
*
(
EWALD_A4
+
t
*
EWALD_A5
))))
*
expm2
;
prefactor
=
qqrd2e
*
tmp_coef3
/
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
=
tmp_coef3
*
table
;
if
(
factor_coul
<
1.0
)
{
table
=
ctable
[
itable
]
+
fraction
*
dctable
[
itable
];
prefactor
=
tmp_coef3
*
table
;
forcecoul
-=
(
1.0
-
factor_coul
)
*
prefactor
;
}
}
}
forcelj
=
0.0
;
if
(
rsq
<
cut_ljsq
)
{
r6inv
=
r2inv
*
r2inv
*
r2inv
;
jtype
=
type
[
j
]
-
1
;
fast_alpha_t
&
a
=
tabsixi
[
jtype
];
forcelj
=
r6inv
*
(
a
.
lj1
*
r6inv
-
a
.
lj2
);
if
(
rsq
>
cut_lj_innersq
)
{
switch1
=
(
cut_ljsq
-
rsq
)
*
(
cut_ljsq
-
rsq
)
*
(
tmp_coef2
+
2.0
*
rsq
)
*
tmp_coef1
;
switch2
=
12.0
*
rsq
*
(
cut_ljsq
-
rsq
)
*
(
rsq
-
cut_lj_innersq
)
*
tmp_coef1
;
fast_alpha_t
&
a
=
tabsixi
[
jtype
];
philj
=
r6inv
*
(
a
.
lj3
*
r6inv
-
a
.
lj4
);
forcelj
=
forcelj
*
switch1
+
philj
*
switch2
;
}
}
double
fpair
=
(
forcecoul
+
factor_lj
*
forcelj
)
*
r2inv
;
tmpfx
+=
delx
*
fpair
;
tmpfy
+=
dely
*
fpair
;
tmpfz
+=
delz
*
fpair
;
if
(
NEWTON_PAIR
||
j
<
nlocal
)
{
ff
[
j
].
x
-=
delx
*
fpair
;
ff
[
j
].
y
-=
dely
*
fpair
;
ff
[
j
].
z
-=
delz
*
fpair
;
}
if
(
EFLAG
)
{
if
(
rsq
<
cut_coulsq
)
{
if
(
!
ncoultablebits
||
rsq
<=
tabinnersq
)
ecoul
=
prefactor
*
erfc
;
else
{
table
=
etable
[
itable
]
+
fraction
*
detable
[
itable
];
ecoul
=
tmp_coef3
*
table
;
}
if
(
factor_coul
<
1.0
)
ecoul
-=
(
1.0
-
factor_coul
)
*
prefactor
;
}
else
ecoul
=
0.0
;
if
(
rsq
<
cut_ljsq
)
{
fast_alpha_t
&
a
=
tabsixi
[
jtype
];
evdwl
=
r6inv
*
(
a
.
lj3
*
r6inv
-
a
.
lj4
);
if
(
rsq
>
cut_lj_innersq
)
{
switch1
=
(
cut_ljsq
-
rsq
)
*
(
cut_ljsq
-
rsq
)
*
(
tmp_coef2
+
2.0
*
rsq
)
*
tmp_coef1
;
evdwl
*=
switch1
;
}
evdwl
*=
factor_lj
;
}
else
evdwl
=
0.0
;
}
if
(
EVFLAG
)
ev_tally
(
i
,
j
,
nlocal
,
NEWTON_PAIR
,
evdwl
,
ecoul
,
fpair
,
delx
,
dely
,
delz
);
}
}
}
ff
[
i
].
x
+=
tmpfx
;
ff
[
i
].
y
+=
tmpfy
;
ff
[
i
].
z
+=
tmpfz
;
}
free
(
fast_alpha
);
fast_alpha
=
0
;
if
(
vflag_fdotr
)
virial_fdotr_compute
();
}
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