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compliance.py
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Created
Thu, Oct 31, 16:48
Size
2 KB
Mime Type
text/x-python
Expires
Sat, Nov 2, 16:48 (1 d, 22 h)
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blob
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Raw Data
Handle
21995314
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rLAMMPS lammps
compliance.py
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#!/usr/bin/env python
# This file reads in the file log.lammps generated by the script ELASTIC/in.elastic
# It prints out the 6x6 tensor of elastic constants Cij
# followed by the 6x6 tensor of compliance constants Sij
# It uses the same conventions as described in:
# Sprik, Impey and Klein PRB (1984).
# The units of Cij are whatever was used in log.lammps (usually GPa)
# The units of Sij are the inverse of that (usually 1/GPa)
from
numpy
import
zeros
from
numpy.linalg
import
inv
# define logfile layout
nvals
=
21
valpos
=
4
valstr
=
'
\n
Elastic Constant C'
# define order of Cij in logfile
cindices
=
[
0
]
*
nvals
cindices
[
0
]
=
(
0
,
0
)
cindices
[
1
]
=
(
1
,
1
)
cindices
[
2
]
=
(
2
,
2
)
cindices
[
3
]
=
(
0
,
1
)
cindices
[
4
]
=
(
0
,
2
)
cindices
[
5
]
=
(
1
,
2
)
cindices
[
6
]
=
(
3
,
3
)
cindices
[
7
]
=
(
4
,
4
)
cindices
[
8
]
=
(
5
,
5
)
cindices
[
9
]
=
(
0
,
3
)
cindices
[
10
]
=
(
0
,
4
)
cindices
[
11
]
=
(
0
,
5
)
cindices
[
12
]
=
(
1
,
3
)
cindices
[
13
]
=
(
1
,
4
)
cindices
[
14
]
=
(
1
,
5
)
cindices
[
15
]
=
(
2
,
3
)
cindices
[
16
]
=
(
2
,
4
)
cindices
[
17
]
=
(
2
,
5
)
cindices
[
18
]
=
(
3
,
4
)
cindices
[
19
]
=
(
3
,
5
)
cindices
[
20
]
=
(
4
,
5
)
# open logfile
logfile
=
open
(
"log.lammps"
,
'r'
)
txt
=
logfile
.
read
()
# search for 21 elastic constants
c
=
zeros
((
6
,
6
))
s2
=
0
for
ival
in
range
(
nvals
):
s1
=
txt
.
find
(
valstr
,
s2
)
if
(
s1
==
-
1
):
print
"Failed to find elastic constants in log file"
exit
(
1
)
s1
+=
1
s2
=
txt
.
find
(
"
\n
"
,
s1
)
line
=
txt
[
s1
:
s2
]
# print line
words
=
line
.
split
()
(
i1
,
i2
)
=
cindices
[
ival
]
c
[
i1
,
i2
]
=
float
(
words
[
valpos
])
c
[
i2
,
i1
]
=
c
[
i1
,
i2
]
print
"C tensor [GPa]"
for
i
in
range
(
6
):
for
j
in
range
(
6
):
print
"
%10.8g
"
%
c
[
i
][
j
],
print
# apply factor of 2 to columns of off-diagonal elements
for
i
in
range
(
6
):
for
j
in
range
(
3
,
6
):
c
[
i
][
j
]
*=
2.0
s
=
inv
(
c
)
# apply factor of 1/2 to columns of off-diagonal elements
for
i
in
range
(
6
):
for
j
in
range
(
3
,
6
):
s
[
i
][
j
]
*=
0.5
print
"S tensor [1/GPa]"
for
i
in
range
(
6
):
for
j
in
range
(
6
):
print
"
%10.8g
"
%
s
[
i
][
j
],
print
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