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compute_hexorder_atom.cpp
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Mon, Sep 23, 02:58
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9 KB
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text/x-c
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Wed, Sep 25, 02:58 (2 d)
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rLAMMPS lammps
compute_hexorder_atom.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 author: Aidan Thompson (SNL)
------------------------------------------------------------------------- */
#include <complex>
#include <string.h>
#include <stdlib.h>
#include "compute_hexorder_atom.h"
#include "atom.h"
#include "update.h"
#include "modify.h"
#include "neighbor.h"
#include "neigh_list.h"
#include "neigh_request.h"
#include "force.h"
#include "pair.h"
#include "comm.h"
#include "memory.h"
#include "error.h"
#include "math_const.h"
#ifdef DBL_EPSILON
#define MY_EPSILON (10.0*DBL_EPSILON)
#else
#define MY_EPSILON (10.0*2.220446049250313e-16)
#endif
using
namespace
LAMMPS_NS
;
using
namespace
MathConst
;
/* ---------------------------------------------------------------------- */
ComputeHexOrderAtom
::
ComputeHexOrderAtom
(
LAMMPS
*
lmp
,
int
narg
,
char
**
arg
)
:
Compute
(
lmp
,
narg
,
arg
),
distsq
(
NULL
),
nearest
(
NULL
),
qnarray
(
NULL
)
{
if
(
narg
<
3
)
error
->
all
(
FLERR
,
"Illegal compute hexorder/atom command"
);
ndegree
=
6
;
nnn
=
6
;
cutsq
=
0.0
;
// process optional args
int
iarg
=
3
;
while
(
iarg
<
narg
)
{
if
(
strcmp
(
arg
[
iarg
],
"degree"
)
==
0
)
{
if
(
iarg
+
2
>
narg
)
error
->
all
(
FLERR
,
"Illegal compute hexorder/atom command"
);
ndegree
=
force
->
numeric
(
FLERR
,
arg
[
iarg
+
1
]);
if
(
ndegree
<
0
)
error
->
all
(
FLERR
,
"Illegal compute hexorder/atom command"
);
iarg
+=
2
;
}
else
if
(
strcmp
(
arg
[
iarg
],
"nnn"
)
==
0
)
{
if
(
iarg
+
2
>
narg
)
error
->
all
(
FLERR
,
"Illegal compute hexorder/atom command"
);
if
(
strcmp
(
arg
[
iarg
+
1
],
"NULL"
)
==
0
)
nnn
=
0
;
else
{
nnn
=
force
->
numeric
(
FLERR
,
arg
[
iarg
+
1
]);
if
(
nnn
<
0
)
error
->
all
(
FLERR
,
"Illegal compute hexorder/atom command"
);
}
iarg
+=
2
;
}
else
if
(
strcmp
(
arg
[
iarg
],
"cutoff"
)
==
0
)
{
if
(
iarg
+
2
>
narg
)
error
->
all
(
FLERR
,
"Illegal compute hexorder/atom command"
);
double
cutoff
=
force
->
numeric
(
FLERR
,
arg
[
iarg
+
1
]);
if
(
cutoff
<=
0.0
)
error
->
all
(
FLERR
,
"Illegal compute hexorder/atom command"
);
cutsq
=
cutoff
*
cutoff
;
iarg
+=
2
;
}
else
error
->
all
(
FLERR
,
"Illegal compute hexorder/atom command"
);
}
ncol
=
2
;
peratom_flag
=
1
;
size_peratom_cols
=
ncol
;
nmax
=
0
;
maxneigh
=
0
;
}
/* ---------------------------------------------------------------------- */
ComputeHexOrderAtom
::~
ComputeHexOrderAtom
()
{
memory
->
destroy
(
qnarray
);
memory
->
destroy
(
distsq
);
memory
->
destroy
(
nearest
);
}
/* ---------------------------------------------------------------------- */
void
ComputeHexOrderAtom
::
init
()
{
if
(
force
->
pair
==
NULL
)
error
->
all
(
FLERR
,
"Compute hexorder/atom requires a pair style be defined"
);
if
(
cutsq
==
0.0
)
cutsq
=
force
->
pair
->
cutforce
*
force
->
pair
->
cutforce
;
else
if
(
sqrt
(
cutsq
)
>
force
->
pair
->
cutforce
)
error
->
all
(
FLERR
,
"Compute hexorder/atom cutoff is longer than pairwise cutoff"
);
// need an occasional full neighbor list
int
irequest
=
neighbor
->
request
(
this
,
instance_me
);
neighbor
->
requests
[
irequest
]
->
pair
=
0
;
neighbor
->
requests
[
irequest
]
->
compute
=
1
;
neighbor
->
requests
[
irequest
]
->
half
=
0
;
neighbor
->
requests
[
irequest
]
->
full
=
1
;
neighbor
->
requests
[
irequest
]
->
occasional
=
1
;
int
count
=
0
;
for
(
int
i
=
0
;
i
<
modify
->
ncompute
;
i
++
)
if
(
strcmp
(
modify
->
compute
[
i
]
->
style
,
"hexorder/atom"
)
==
0
)
count
++
;
if
(
count
>
1
&&
comm
->
me
==
0
)
error
->
warning
(
FLERR
,
"More than one compute hexorder/atom"
);
}
/* ---------------------------------------------------------------------- */
void
ComputeHexOrderAtom
::
init_list
(
int
id
,
NeighList
*
ptr
)
{
list
=
ptr
;
}
/* ---------------------------------------------------------------------- */
void
ComputeHexOrderAtom
::
compute_peratom
()
{
int
i
,
j
,
ii
,
jj
,
inum
,
jnum
;
double
xtmp
,
ytmp
,
ztmp
,
delx
,
dely
,
delz
,
rsq
;
int
*
ilist
,
*
jlist
,
*
numneigh
,
**
firstneigh
;
invoked_peratom
=
update
->
ntimestep
;
// grow order parameter array if necessary
if
(
atom
->
nmax
>
nmax
)
{
memory
->
destroy
(
qnarray
);
nmax
=
atom
->
nmax
;
memory
->
create
(
qnarray
,
nmax
,
ncol
,
"hexorder/atom:qnarray"
);
array_atom
=
qnarray
;
}
// invoke full neighbor list (will copy or build if necessary)
neighbor
->
build_one
(
list
);
inum
=
list
->
inum
;
ilist
=
list
->
ilist
;
numneigh
=
list
->
numneigh
;
firstneigh
=
list
->
firstneigh
;
// compute order parameter for each atom in group
// use full neighbor list to count atoms less than cutoff
double
**
x
=
atom
->
x
;
int
*
mask
=
atom
->
mask
;
for
(
ii
=
0
;
ii
<
inum
;
ii
++
)
{
i
=
ilist
[
ii
];
double
*
qn
=
qnarray
[
i
];
if
(
mask
[
i
]
&
groupbit
)
{
xtmp
=
x
[
i
][
0
];
ytmp
=
x
[
i
][
1
];
ztmp
=
x
[
i
][
2
];
jlist
=
firstneigh
[
i
];
jnum
=
numneigh
[
i
];
// insure distsq and nearest arrays are long enough
if
(
jnum
>
maxneigh
)
{
memory
->
destroy
(
distsq
);
memory
->
destroy
(
nearest
);
maxneigh
=
jnum
;
memory
->
create
(
distsq
,
maxneigh
,
"hexorder/atom:distsq"
);
memory
->
create
(
nearest
,
maxneigh
,
"hexorder/atom:nearest"
);
}
// loop over list of all neighbors within force cutoff
// distsq[] = distance sq to each
// nearest[] = atom indices of neighbors
int
ncount
=
0
;
for
(
jj
=
0
;
jj
<
jnum
;
jj
++
)
{
j
=
jlist
[
jj
];
j
&=
NEIGHMASK
;
delx
=
xtmp
-
x
[
j
][
0
];
dely
=
ytmp
-
x
[
j
][
1
];
delz
=
ztmp
-
x
[
j
][
2
];
rsq
=
delx
*
delx
+
dely
*
dely
+
delz
*
delz
;
if
(
rsq
<
cutsq
)
{
distsq
[
ncount
]
=
rsq
;
nearest
[
ncount
++
]
=
j
;
}
}
// if not nnn neighbors, order parameter = 0;
if
(
ncount
<
nnn
)
{
qn
[
0
]
=
qn
[
1
]
=
0.0
;
continue
;
}
// if nnn > 0, use only nearest nnn neighbors
if
(
nnn
>
0
)
{
select2
(
nnn
,
ncount
,
distsq
,
nearest
);
ncount
=
nnn
;
}
double
usum
=
0.0
;
double
vsum
=
0.0
;
for
(
jj
=
0
;
jj
<
ncount
;
jj
++
)
{
j
=
nearest
[
jj
];
j
&=
NEIGHMASK
;
delx
=
xtmp
-
x
[
j
][
0
];
dely
=
ytmp
-
x
[
j
][
1
];
double
u
,
v
;
calc_qn_complex
(
delx
,
dely
,
u
,
v
);
usum
+=
u
;
vsum
+=
v
;
}
qn
[
0
]
=
usum
/
nnn
;
qn
[
1
]
=
vsum
/
nnn
;
}
}
}
// calculate order parameter using std::complex::pow function
inline
void
ComputeHexOrderAtom
::
calc_qn_complex
(
double
delx
,
double
dely
,
double
&
u
,
double
&
v
)
{
double
rinv
=
1.0
/
sqrt
(
delx
*
delx
+
dely
*
dely
);
double
x
=
delx
*
rinv
;
double
y
=
dely
*
rinv
;
std
::
complex
<
double
>
z
(
x
,
y
);
std
::
complex
<
double
>
zn
=
pow
(
z
,
ndegree
);
u
=
real
(
zn
);
v
=
imag
(
zn
);
}
// calculate order parameter using trig functions
// this is usually slower, but can be used if <complex> not available
inline
void
ComputeHexOrderAtom
::
calc_qn_trig
(
double
delx
,
double
dely
,
double
&
u
,
double
&
v
)
{
double
ntheta
;
if
(
fabs
(
delx
)
<=
MY_EPSILON
)
{
if
(
dely
>
0.0
)
ntheta
=
ndegree
*
MY_PI
/
2.0
;
else
ntheta
=
ndegree
*
3.0
*
MY_PI
/
2.0
;
}
else
ntheta
=
ndegree
*
atan
(
dely
/
delx
);
u
=
cos
(
ntheta
);
v
=
sin
(
ntheta
);
}
/* ----------------------------------------------------------------------
select2 routine from Numerical Recipes (slightly modified)
find k smallest values in array of length n
sort auxiliary array at same time
------------------------------------------------------------------------- */
#define SWAP(a,b) tmp = a; a = b; b = tmp;
#define ISWAP(a,b) itmp = a; a = b; b = itmp;
/* ---------------------------------------------------------------------- */
void
ComputeHexOrderAtom
::
select2
(
int
k
,
int
n
,
double
*
arr
,
int
*
iarr
)
{
int
i
,
ir
,
j
,
l
,
mid
,
ia
,
itmp
;
double
a
,
tmp
;
arr
--
;
iarr
--
;
l
=
1
;
ir
=
n
;
for
(;;)
{
if
(
ir
<=
l
+
1
)
{
if
(
ir
==
l
+
1
&&
arr
[
ir
]
<
arr
[
l
])
{
SWAP
(
arr
[
l
],
arr
[
ir
])
ISWAP
(
iarr
[
l
],
iarr
[
ir
])
}
return
;
}
else
{
mid
=
(
l
+
ir
)
>>
1
;
SWAP
(
arr
[
mid
],
arr
[
l
+
1
])
ISWAP
(
iarr
[
mid
],
iarr
[
l
+
1
])
if
(
arr
[
l
]
>
arr
[
ir
])
{
SWAP
(
arr
[
l
],
arr
[
ir
])
ISWAP
(
iarr
[
l
],
iarr
[
ir
])
}
if
(
arr
[
l
+
1
]
>
arr
[
ir
])
{
SWAP
(
arr
[
l
+
1
],
arr
[
ir
])
ISWAP
(
iarr
[
l
+
1
],
iarr
[
ir
])
}
if
(
arr
[
l
]
>
arr
[
l
+
1
])
{
SWAP
(
arr
[
l
],
arr
[
l
+
1
])
ISWAP
(
iarr
[
l
],
iarr
[
l
+
1
])
}
i
=
l
+
1
;
j
=
ir
;
a
=
arr
[
l
+
1
];
ia
=
iarr
[
l
+
1
];
for
(;;)
{
do
i
++
;
while
(
arr
[
i
]
<
a
);
do
j
--
;
while
(
arr
[
j
]
>
a
);
if
(
j
<
i
)
break
;
SWAP
(
arr
[
i
],
arr
[
j
])
ISWAP
(
iarr
[
i
],
iarr
[
j
])
}
arr
[
l
+
1
]
=
arr
[
j
];
arr
[
j
]
=
a
;
iarr
[
l
+
1
]
=
iarr
[
j
];
iarr
[
j
]
=
ia
;
if
(
j
>=
k
)
ir
=
j
-
1
;
if
(
j
<=
k
)
l
=
i
;
}
}
}
/* ----------------------------------------------------------------------
memory usage of local atom-based array
------------------------------------------------------------------------- */
double
ComputeHexOrderAtom
::
memory_usage
()
{
double
bytes
=
ncol
*
nmax
*
sizeof
(
double
);
bytes
+=
maxneigh
*
sizeof
(
double
);
bytes
+=
maxneigh
*
sizeof
(
int
);
return
bytes
;
}
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