Page Menu
Home
c4science
Search
Configure Global Search
Log In
Files
F78291614
fix_nve.cpp
No One
Temporary
Actions
Download File
Edit File
Delete File
View Transforms
Subscribe
Mute Notifications
Award Token
Subscribers
None
File Metadata
Details
File Info
Storage
Attached
Created
Mon, Aug 19, 15:46
Size
4 KB
Mime Type
text/x-c
Expires
Wed, Aug 21, 15:46 (1 d, 22 h)
Engine
blob
Format
Raw Data
Handle
20022238
Attached To
rLAMMPS lammps
fix_nve.cpp
View Options
/* ----------------------------------------------------------------------
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 "stdio.h"
#include "string.h"
#include "fix_nve.h"
#include "atom.h"
#include "force.h"
#include "update.h"
#include "respa.h"
#include "error.h"
using
namespace
LAMMPS_NS
;
/* ---------------------------------------------------------------------- */
FixNVE
::
FixNVE
(
LAMMPS
*
lmp
,
int
narg
,
char
**
arg
)
:
Fix
(
lmp
,
narg
,
arg
)
{
if
(
strcmp
(
style
,
"nve/sphere"
)
!=
0
&&
narg
<
3
)
error
->
all
(
"Illegal fix nve command"
);
time_integrate
=
1
;
}
/* ---------------------------------------------------------------------- */
int
FixNVE
::
setmask
()
{
int
mask
=
0
;
mask
|=
INITIAL_INTEGRATE
;
mask
|=
FINAL_INTEGRATE
;
mask
|=
INITIAL_INTEGRATE_RESPA
;
mask
|=
FINAL_INTEGRATE_RESPA
;
return
mask
;
}
/* ---------------------------------------------------------------------- */
void
FixNVE
::
init
()
{
dtv
=
update
->
dt
;
dtf
=
0.5
*
update
->
dt
*
force
->
ftm2v
;
if
(
strcmp
(
update
->
integrate_style
,
"respa"
)
==
0
)
step_respa
=
((
Respa
*
)
update
->
integrate
)
->
step
;
}
/* ----------------------------------------------------------------------
allow for both per-type and per-atom mass
------------------------------------------------------------------------- */
void
FixNVE
::
initial_integrate
(
int
vflag
)
{
double
dtfm
;
// update v and x of atoms in group
double
**
x
=
atom
->
x
;
double
**
v
=
atom
->
v
;
double
**
f
=
atom
->
f
;
double
*
rmass
=
atom
->
rmass
;
double
*
mass
=
atom
->
mass
;
int
*
type
=
atom
->
type
;
int
*
mask
=
atom
->
mask
;
int
nlocal
=
atom
->
nlocal
;
if
(
igroup
==
atom
->
firstgroup
)
nlocal
=
atom
->
nfirst
;
if
(
rmass
)
{
for
(
int
i
=
0
;
i
<
nlocal
;
i
++
)
{
if
(
mask
[
i
]
&
groupbit
)
{
dtfm
=
dtf
/
rmass
[
i
];
v
[
i
][
0
]
+=
dtfm
*
f
[
i
][
0
];
v
[
i
][
1
]
+=
dtfm
*
f
[
i
][
1
];
v
[
i
][
2
]
+=
dtfm
*
f
[
i
][
2
];
x
[
i
][
0
]
+=
dtv
*
v
[
i
][
0
];
x
[
i
][
1
]
+=
dtv
*
v
[
i
][
1
];
x
[
i
][
2
]
+=
dtv
*
v
[
i
][
2
];
}
}
}
else
{
for
(
int
i
=
0
;
i
<
nlocal
;
i
++
)
{
if
(
mask
[
i
]
&
groupbit
)
{
dtfm
=
dtf
/
mass
[
type
[
i
]];
v
[
i
][
0
]
+=
dtfm
*
f
[
i
][
0
];
v
[
i
][
1
]
+=
dtfm
*
f
[
i
][
1
];
v
[
i
][
2
]
+=
dtfm
*
f
[
i
][
2
];
x
[
i
][
0
]
+=
dtv
*
v
[
i
][
0
];
x
[
i
][
1
]
+=
dtv
*
v
[
i
][
1
];
x
[
i
][
2
]
+=
dtv
*
v
[
i
][
2
];
}
}
}
}
/* ---------------------------------------------------------------------- */
void
FixNVE
::
final_integrate
()
{
double
dtfm
;
// update v of atoms in group
double
**
v
=
atom
->
v
;
double
**
f
=
atom
->
f
;
double
*
rmass
=
atom
->
rmass
;
double
*
mass
=
atom
->
mass
;
int
*
type
=
atom
->
type
;
int
*
mask
=
atom
->
mask
;
int
nlocal
=
atom
->
nlocal
;
if
(
igroup
==
atom
->
firstgroup
)
nlocal
=
atom
->
nfirst
;
if
(
rmass
)
{
for
(
int
i
=
0
;
i
<
nlocal
;
i
++
)
{
if
(
mask
[
i
]
&
groupbit
)
{
dtfm
=
dtf
/
rmass
[
i
];
v
[
i
][
0
]
+=
dtfm
*
f
[
i
][
0
];
v
[
i
][
1
]
+=
dtfm
*
f
[
i
][
1
];
v
[
i
][
2
]
+=
dtfm
*
f
[
i
][
2
];
}
}
}
else
{
for
(
int
i
=
0
;
i
<
nlocal
;
i
++
)
{
if
(
mask
[
i
]
&
groupbit
)
{
dtfm
=
dtf
/
mass
[
type
[
i
]];
v
[
i
][
0
]
+=
dtfm
*
f
[
i
][
0
];
v
[
i
][
1
]
+=
dtfm
*
f
[
i
][
1
];
v
[
i
][
2
]
+=
dtfm
*
f
[
i
][
2
];
}
}
}
}
/* ---------------------------------------------------------------------- */
void
FixNVE
::
initial_integrate_respa
(
int
vflag
,
int
ilevel
,
int
flag
)
{
if
(
flag
)
return
;
// only used by NPT,NPH
dtv
=
step_respa
[
ilevel
];
dtf
=
0.5
*
step_respa
[
ilevel
]
*
force
->
ftm2v
;
// innermost level - NVE update of v and x
// all other levels - NVE update of v
if
(
ilevel
==
0
)
initial_integrate
(
vflag
);
else
final_integrate
();
}
/* ---------------------------------------------------------------------- */
void
FixNVE
::
final_integrate_respa
(
int
ilevel
)
{
dtf
=
0.5
*
step_respa
[
ilevel
]
*
force
->
ftm2v
;
final_integrate
();
}
/* ---------------------------------------------------------------------- */
void
FixNVE
::
reset_dt
()
{
dtv
=
update
->
dt
;
dtf
=
0.5
*
update
->
dt
*
force
->
ftm2v
;
}
Event Timeline
Log In to Comment