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Stephan Seitz
pystencils
Commits
cfa9ec1d
Commit
cfa9ec1d
authored
Feb 12, 2020
by
Michael Kuron
Browse files
FVM derivation: use a smaller stencil before trying bruteforce to find the sparsest stencil
parent
0bb88bca
Changes
1
Hide whitespace changes
Inline
Sidebyside
pystencils/fd/finitevolumes.py
View file @
cfa9ec1d
...
...
@@ 123,30 +123,35 @@ class FVM1stOrder:
else
:
stencil
=
[
""
.
join
(
a
).
replace
(
" "
,
""
)
for
a
in
itertools
.
product
(
"NS "
,
"EW "
,
"TB "
)
if
""
.
join
(
a
).
strip
()]
stencil
=
[
tuple
(
ps
.
stencil
.
direction_string_to_offset
(
d
,
self
.
dim
))
for
d
in
stencil
]
derivation
=
FD
(
direction
,
stencil
).
get_stencil
()
if
not
derivation
.
accuracy
:
weights
=
None
for
stencil
in
[[
"N"
,
"S"
,
"E"
,
"W"
,
"T"
,
"B"
][:
2
*
self
.
dim
],
stencil
]:
stencil
=
[
tuple
(
ps
.
stencil
.
direction_string_to_offset
(
d
,
self
.
dim
))
for
d
in
stencil
]
derivation
=
FD
(
direction
,
stencil
).
get_stencil
()
if
not
derivation
.
accuracy
:
continue
weights
=
derivation
.
weights
# if the weights are underdefined, we can choose the free symbols to find the sparsest stencil
free_weights
=
set
(
itertools
.
chain
(
*
[
w
.
free_symbols
for
w
in
weights
]))
if
len
(
free_weights
)
>
0
:
zero_counts
=
defaultdict
(
list
)
for
values
in
itertools
.
product
([

1
,

sp
.
Rational
(
1
,
2
),
0
,
1
,
sp
.
Rational
(
1
,
2
)],
repeat
=
len
(
free_weights
)):
subs
=
{
free_weight
:
value
for
free_weight
,
value
in
zip
(
free_weights
,
values
)}
weights
=
[
w
.
subs
(
subs
)
for
w
in
derivation
.
weights
]
if
not
all
(
a
==
0
for
a
in
weights
):
zero_count
=
sum
([
1
for
w
in
weights
if
w
==
0
])
zero_counts
[
zero_count
].
append
(
weights
)
best
=
zero_counts
[
max
(
zero_counts
.
keys
())]
if
len
(
best
)
>
1
:
raise
NotImplementedError
(
"more than one suitable set of weights found, "
"don't know how to proceed"
)
weights
=
best
[
0
]
break
if
not
weights
:
raise
Exception
(
'the requested derivative cannot be performed with the available neighbors'
)
weights
=
derivation
.
weights
# if the weights are underdefined, we can choose the free symbols to find the sparsest stencil
free_weights
=
set
(
itertools
.
chain
(
*
[
w
.
free_symbols
for
w
in
weights
]))
if
len
(
free_weights
)
>
0
:
zero_counts
=
defaultdict
(
list
)
for
values
in
itertools
.
product
([

1
,

sp
.
Rational
(
1
,
2
),
0
,
1
,
sp
.
Rational
(
1
,
2
)],
repeat
=
len
(
free_weights
)):
subs
=
{
free_weight
:
value
for
free_weight
,
value
in
zip
(
free_weights
,
values
)}
weights
=
[
w
.
subs
(
subs
)
for
w
in
derivation
.
weights
]
if
not
all
(
a
==
0
for
a
in
weights
):
zero_count
=
sum
([
1
for
w
in
weights
if
w
==
0
])
zero_counts
[
zero_count
].
append
(
weights
)
best
=
zero_counts
[
max
(
zero_counts
.
keys
())]
if
len
(
best
)
>
1
:
raise
NotImplementedError
(
"more than one suitable set of weights found, "
"don't know how to proceed"
)
weights
=
best
[
0
]
assert
weights
assert
weights
if
access
.
_field
.
index_dimensions
==
0
:
return
sum
([
access
.
_field
.
__getitem__
(
point
)
*
weight
for
point
,
weight
in
zip
(
stencil
,
weights
)])
...
...
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