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fix_dt_reset.cpp
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Created
Tue, Oct 1, 02:38
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5 KB
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text/x-c
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Thu, Oct 3, 02:38 (2 d)
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rLAMMPS lammps
fix_dt_reset.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 "string.h"
#include "fix_dt_reset.h"
#include "atom.h"
#include "update.h"
#include "integrate.h"
#include "domain.h"
#include "lattice.h"
#include "force.h"
#include "pair.h"
#include "modify.h"
#include "fix.h"
#include "output.h"
#include "dump.h"
#include "comm.h"
#include "error.h"
using
namespace
LAMMPS_NS
;
#define BIG 1.0e20
#define MIN(A,B) ((A) < (B)) ? (A) : (B)
#define MAX(A,B) ((A) > (B)) ? (A) : (B)
/* ---------------------------------------------------------------------- */
FixDtReset
::
FixDtReset
(
LAMMPS
*
lmp
,
int
narg
,
char
**
arg
)
:
Fix
(
lmp
,
narg
,
arg
)
{
if
(
narg
<
7
)
error
->
all
(
"Illegal fix dt/reset command"
);
scalar_flag
=
1
;
vector_flag
=
1
;
size_vector
=
1
;
scalar_vector_freq
=
1
;
extensive
=
0
;
nevery
=
atoi
(
arg
[
3
]);
if
(
nevery
<=
0
)
error
->
all
(
"Illegal fix dt/reset command"
);
minbound
=
maxbound
=
1
;
tmin
=
tmax
=
0.0
;
if
(
strcmp
(
arg
[
4
],
"INF"
)
==
0
)
minbound
=
0
;
else
tmin
=
atof
(
arg
[
4
]);
if
(
strcmp
(
arg
[
5
],
"INF"
)
==
0
)
maxbound
=
0
;
else
tmax
=
atof
(
arg
[
5
]);
xmax
=
atof
(
arg
[
6
]);
if
(
minbound
&&
tmin
<
0.0
)
error
->
all
(
"Illegal fix dt/reset command"
);
if
(
maxbound
&&
tmax
<
0.0
)
error
->
all
(
"Illegal fix dt/reset command"
);
if
(
minbound
&&
maxbound
&&
tmin
>
tmax
)
error
->
all
(
"Illegal fix dt/reset command"
);
if
(
xmax
<=
0.0
)
error
->
all
(
"Illegal fix dt/reset command"
);
int
scaleflag
=
1
;
int
iarg
=
7
;
while
(
iarg
<
narg
)
{
if
(
strcmp
(
arg
[
iarg
],
"units"
)
==
0
)
{
if
(
iarg
+
2
>
narg
)
error
->
all
(
"Illegal fix dt/reset command"
);
if
(
strcmp
(
arg
[
iarg
+
1
],
"box"
)
==
0
)
scaleflag
=
0
;
else
if
(
strcmp
(
arg
[
iarg
+
1
],
"lattice"
)
==
0
)
scaleflag
=
1
;
else
error
->
all
(
"Illegal fix dt/reset command"
);
iarg
+=
2
;
}
else
error
->
all
(
"Illegal fix dt/reset command"
);
}
// setup scaling, based on xlattice parameter
if
(
scaleflag
&&
domain
->
lattice
==
NULL
)
error
->
all
(
"Use of fix dt/reset with undefined lattice"
);
if
(
scaleflag
)
xmax
*=
domain
->
lattice
->
xlattice
;
// initializations
t_elapsed
=
0.0
;
laststep
=
update
->
ntimestep
;
}
/* ---------------------------------------------------------------------- */
int
FixDtReset
::
setmask
()
{
int
mask
=
0
;
mask
|=
END_OF_STEP
;
return
mask
;
}
/* ---------------------------------------------------------------------- */
void
FixDtReset
::
init
()
{
// set rRESPA flag
respaflag
=
0
;
if
(
strcmp
(
update
->
integrate_style
,
"respa"
)
==
0
)
respaflag
=
1
;
// check for DCD or XTC dumps
for
(
int
i
=
0
;
i
<
output
->
ndump
;
i
++
)
if
((
strcmp
(
output
->
dump
[
i
]
->
style
,
"dcd"
)
==
0
||
strcmp
(
output
->
dump
[
i
]
->
style
,
"xtc"
)
==
0
)
&&
comm
->
me
==
0
)
error
->
warning
(
"Dump dcd/xtc timestamp may be wrong with fix dt/reset"
);
}
/* ---------------------------------------------------------------------- */
void
FixDtReset
::
setup
()
{
end_of_step
();
}
/* ---------------------------------------------------------------------- */
void
FixDtReset
::
end_of_step
()
{
// accumulate total time based on previous timestep
t_elapsed
+=
(
update
->
ntimestep
-
laststep
)
*
update
->
dt
;
// compute vmax and amax of any atom in group
double
**
v
=
atom
->
v
;
double
**
f
=
atom
->
f
;
double
*
mass
=
atom
->
mass
;
double
*
rmass
=
atom
->
rmass
;
int
*
type
=
atom
->
type
;
int
*
mask
=
atom
->
mask
;
int
nlocal
=
atom
->
nlocal
;
double
vsq
,
fsq
,
asq
,
ms
;
double
bound
[
2
],
bound_all
[
2
];
bound
[
0
]
=
bound
[
1
]
=
0.0
;
for
(
int
i
=
0
;
i
<
nlocal
;
i
++
)
if
(
mask
[
i
]
&
groupbit
)
{
vsq
=
v
[
i
][
0
]
*
v
[
i
][
0
]
+
v
[
i
][
1
]
*
v
[
i
][
1
]
+
v
[
i
][
2
]
*
v
[
i
][
2
];
fsq
=
f
[
i
][
0
]
*
f
[
i
][
0
]
+
f
[
i
][
1
]
*
f
[
i
][
1
]
+
f
[
i
][
2
]
*
f
[
i
][
2
];
if
(
mass
)
ms
=
mass
[
type
[
i
]];
else
ms
=
rmass
[
i
];
asq
=
fsq
/
ms
/
ms
;
bound
[
0
]
=
MAX
(
bound
[
0
],
vsq
);
bound
[
1
]
=
MAX
(
bound
[
1
],
asq
);
}
MPI_Allreduce
(
bound
,
bound_all
,
2
,
MPI_DOUBLE
,
MPI_MAX
,
world
);
// set new timestep
double
dt
,
dt1
,
dt2
;
if
(
bound_all
[
0
]
>
0.0
)
dt1
=
xmax
/
sqrt
(
bound_all
[
0
]);
else
dt1
=
BIG
;
if
(
bound_all
[
1
]
>
0.0
)
dt2
=
sqrt
(
2.0
*
xmax
/
sqrt
(
bound_all
[
1
]));
else
dt2
=
BIG
;
dt
=
MIN
(
dt1
,
dt2
);
if
(
minbound
)
dt
=
MAX
(
dt
,
tmin
);
if
(
maxbound
)
dt
=
MIN
(
dt
,
tmax
);
// reset update->dt and other classes that depend on it
// rRESPA, pair style, fixes
laststep
=
update
->
ntimestep
;
if
(
dt
==
update
->
dt
)
return
;
update
->
dt
=
dt
;
if
(
respaflag
)
update
->
integrate
->
reset_dt
();
if
(
force
->
pair
)
force
->
pair
->
reset_dt
();
for
(
int
i
=
0
;
i
<
modify
->
nfix
;
i
++
)
modify
->
fix
[
i
]
->
reset_dt
();
}
/* ---------------------------------------------------------------------- */
double
FixDtReset
::
compute_scalar
()
{
return
update
->
dt
;
}
/* ---------------------------------------------------------------------- */
double
FixDtReset
::
compute_vector
(
int
n
)
{
return
t_elapsed
;
}
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