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pair_dpd_tstat_omp.cpp
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Tue, Oct 8, 21:34
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text/x-c++
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Thu, Oct 10, 21:34 (2 d)
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rLAMMPS lammps
pair_dpd_tstat_omp.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
This software is distributed under the GNU General Public License.
See the README file in the top-level LAMMPS directory.
------------------------------------------------------------------------- */
/* ----------------------------------------------------------------------
Contributing author: Axel Kohlmeyer (Temple U)
------------------------------------------------------------------------- */
#include <math.h>
#include "pair_dpd_tstat_omp.h"
#include "atom.h"
#include "comm.h"
#include "force.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "update.h"
#include "random_mars.h"
#include "suffix.h"
using
namespace
LAMMPS_NS
;
#define EPSILON 1.0e-10
/* ---------------------------------------------------------------------- */
PairDPDTstatOMP
::
PairDPDTstatOMP
(
LAMMPS
*
lmp
)
:
PairDPDTstat
(
lmp
),
ThrOMP
(
lmp
,
THR_PAIR
)
{
suffix_flag
|=
Suffix
::
OMP
;
respa_enable
=
0
;
random_thr
=
NULL
;
nthreads
=
0
;
}
/* ---------------------------------------------------------------------- */
PairDPDTstatOMP
::~
PairDPDTstatOMP
()
{
if
(
random_thr
)
{
for
(
int
i
=
1
;
i
<
nthreads
;
++
i
)
delete
random_thr
[
i
];
delete
[]
random_thr
;
random_thr
=
NULL
;
}
}
/* ---------------------------------------------------------------------- */
void
PairDPDTstatOMP
::
compute
(
int
eflag
,
int
vflag
)
{
if
(
eflag
||
vflag
)
{
ev_setup
(
eflag
,
vflag
);
}
else
evflag
=
vflag_fdotr
=
0
;
const
int
nall
=
atom
->
nlocal
+
atom
->
nghost
;
const
int
inum
=
list
->
inum
;
// number of threads has changed. reallocate pool of pRNGs
if
(
nthreads
!=
comm
->
nthreads
)
{
if
(
random_thr
)
{
for
(
int
i
=
1
;
i
<
nthreads
;
++
i
)
delete
random_thr
[
i
];
delete
[]
random_thr
;
}
nthreads
=
comm
->
nthreads
;
random_thr
=
new
RanMars
*
[
nthreads
];
for
(
int
i
=
1
;
i
<
nthreads
;
++
i
)
random_thr
[
i
]
=
NULL
;
// to ensure full compatibility with the serial DPD style
// we use the serial random number generator instance for thread 0
random_thr
[
0
]
=
random
;
}
#if defined(_OPENMP)
#pragma omp parallel default(none) shared(eflag,vflag)
#endif
{
int
ifrom
,
ito
,
tid
;
loop_setup_thr
(
ifrom
,
ito
,
tid
,
inum
,
nthreads
);
ThrData
*
thr
=
fix
->
get_thr
(
tid
);
thr
->
timer
(
Timer
::
START
);
ev_setup_thr
(
eflag
,
vflag
,
nall
,
eatom
,
vatom
,
thr
);
// generate a random number generator instance for
// all threads != 0. make sure we use unique seeds.
if
((
tid
>
0
)
&&
(
random_thr
[
tid
]
==
NULL
))
random_thr
[
tid
]
=
new
RanMars
(
Pair
::
lmp
,
seed
+
comm
->
me
+
comm
->
nprocs
*
tid
);
if
(
evflag
)
{
if
(
eflag
)
{
if
(
force
->
newton_pair
)
eval
<
1
,
1
,
1
>
(
ifrom
,
ito
,
thr
);
else
eval
<
1
,
1
,
0
>
(
ifrom
,
ito
,
thr
);
}
else
{
if
(
force
->
newton_pair
)
eval
<
1
,
0
,
1
>
(
ifrom
,
ito
,
thr
);
else
eval
<
1
,
0
,
0
>
(
ifrom
,
ito
,
thr
);
}
}
else
{
if
(
force
->
newton_pair
)
eval
<
0
,
0
,
1
>
(
ifrom
,
ito
,
thr
);
else
eval
<
0
,
0
,
0
>
(
ifrom
,
ito
,
thr
);
}
thr
->
timer
(
Timer
::
PAIR
);
reduce_thr
(
this
,
eflag
,
vflag
,
thr
);
}
// end of omp parallel region
}
template
<
int
EVFLAG
,
int
EFLAG
,
int
NEWTON_PAIR
>
void
PairDPDTstatOMP
::
eval
(
int
iifrom
,
int
iito
,
ThrData
*
const
thr
)
{
int
i
,
j
,
ii
,
jj
,
jnum
,
itype
,
jtype
;
double
xtmp
,
ytmp
,
ztmp
,
delx
,
dely
,
delz
,
fpair
;
double
vxtmp
,
vytmp
,
vztmp
,
delvx
,
delvy
,
delvz
;
double
rsq
,
r
,
rinv
,
dot
,
wd
,
randnum
,
factor_dpd
;
int
*
ilist
,
*
jlist
,
*
numneigh
,
**
firstneigh
;
const
dbl3_t
*
_noalias
const
x
=
(
dbl3_t
*
)
atom
->
x
[
0
];
const
dbl3_t
*
_noalias
const
v
=
(
dbl3_t
*
)
atom
->
v
[
0
];
dbl3_t
*
_noalias
const
f
=
(
dbl3_t
*
)
thr
->
get_f
()[
0
];
const
int
*
_noalias
const
type
=
atom
->
type
;
const
int
nlocal
=
atom
->
nlocal
;
const
double
*
special_lj
=
force
->
special_lj
;
const
double
dtinvsqrt
=
1.0
/
sqrt
(
update
->
dt
);
double
fxtmp
,
fytmp
,
fztmp
;
RanMars
&
rng
=
*
random_thr
[
thr
->
get_tid
()];
// adjust sigma if target T is changing
if
(
t_start
!=
t_stop
)
{
double
delta
=
update
->
ntimestep
-
update
->
beginstep
;
delta
/=
update
->
endstep
-
update
->
beginstep
;
temperature
=
t_start
+
delta
*
(
t_stop
-
t_start
);
double
boltz
=
force
->
boltz
;
for
(
i
=
1
;
i
<=
atom
->
ntypes
;
i
++
)
for
(
j
=
i
;
j
<=
atom
->
ntypes
;
j
++
)
sigma
[
i
][
j
]
=
sigma
[
j
][
i
]
=
sqrt
(
2.0
*
boltz
*
temperature
*
gamma
[
i
][
j
]);
}
ilist
=
list
->
ilist
;
numneigh
=
list
->
numneigh
;
firstneigh
=
list
->
firstneigh
;
// loop over neighbors of my atoms
for
(
ii
=
iifrom
;
ii
<
iito
;
++
ii
)
{
i
=
ilist
[
ii
];
xtmp
=
x
[
i
].
x
;
ytmp
=
x
[
i
].
y
;
ztmp
=
x
[
i
].
z
;
vxtmp
=
v
[
i
].
x
;
vytmp
=
v
[
i
].
y
;
vztmp
=
v
[
i
].
z
;
itype
=
type
[
i
];
jlist
=
firstneigh
[
i
];
jnum
=
numneigh
[
i
];
fxtmp
=
fytmp
=
fztmp
=
0.0
;
for
(
jj
=
0
;
jj
<
jnum
;
jj
++
)
{
j
=
jlist
[
jj
];
factor_dpd
=
special_lj
[
sbmask
(
j
)];
j
&=
NEIGHMASK
;
delx
=
xtmp
-
x
[
j
].
x
;
dely
=
ytmp
-
x
[
j
].
y
;
delz
=
ztmp
-
x
[
j
].
z
;
rsq
=
delx
*
delx
+
dely
*
dely
+
delz
*
delz
;
jtype
=
type
[
j
];
if
(
rsq
<
cutsq
[
itype
][
jtype
])
{
r
=
sqrt
(
rsq
);
if
(
r
<
EPSILON
)
continue
;
// r can be 0.0 in DPD systems
rinv
=
1.0
/
r
;
delvx
=
vxtmp
-
v
[
j
].
x
;
delvy
=
vytmp
-
v
[
j
].
y
;
delvz
=
vztmp
-
v
[
j
].
z
;
dot
=
delx
*
delvx
+
dely
*
delvy
+
delz
*
delvz
;
wd
=
1.0
-
r
/
cut
[
itype
][
jtype
];
randnum
=
rng
.
gaussian
();
// drag force = -gamma * wd^2 * (delx dot delv) / r
// random force = sigma * wd * rnd * dtinvsqrt;
fpair
=
-
gamma
[
itype
][
jtype
]
*
wd
*
wd
*
dot
*
rinv
;
fpair
+=
sigma
[
itype
][
jtype
]
*
wd
*
randnum
*
dtinvsqrt
;
fpair
*=
factor_dpd
*
rinv
;
fxtmp
+=
delx
*
fpair
;
fytmp
+=
dely
*
fpair
;
fztmp
+=
delz
*
fpair
;
if
(
NEWTON_PAIR
||
j
<
nlocal
)
{
f
[
j
].
x
-=
delx
*
fpair
;
f
[
j
].
y
-=
dely
*
fpair
;
f
[
j
].
z
-=
delz
*
fpair
;
}
if
(
EVFLAG
)
ev_tally_thr
(
this
,
i
,
j
,
nlocal
,
NEWTON_PAIR
,
0.0
,
0.0
,
fpair
,
delx
,
dely
,
delz
,
thr
);
}
}
f
[
i
].
x
+=
fxtmp
;
f
[
i
].
y
+=
fytmp
;
f
[
i
].
z
+=
fztmp
;
}
}
/* ---------------------------------------------------------------------- */
double
PairDPDTstatOMP
::
memory_usage
()
{
double
bytes
=
memory_usage_thr
();
bytes
+=
PairDPDTstat
::
memory_usage
();
bytes
+=
comm
->
nthreads
*
sizeof
(
RanMars
*
);
bytes
+=
comm
->
nthreads
*
sizeof
(
RanMars
);
return
bytes
;
}
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