Skip to content
GitLab
Projects
Groups
Snippets
Help
Loading...
Help
Help
Support
Community forum
Keyboard shortcuts
?
Submit feedback
Contribute to GitLab
Sign in
Toggle navigation
N
NIFTy
Project overview
Project overview
Details
Activity
Releases
Repository
Repository
Files
Commits
Branches
Tags
Contributors
Graph
Compare
Issues
14
Issues
14
List
Boards
Labels
Service Desk
Milestones
Merge Requests
10
Merge Requests
10
CI / CD
CI / CD
Pipelines
Jobs
Schedules
Operations
Operations
Environments
Packages & Registries
Packages & Registries
Container Registry
Analytics
Analytics
CI / CD
Repository
Value Stream
Members
Members
Collapse sidebar
Close sidebar
Activity
Graph
Create a new issue
Jobs
Commits
Issue Boards
Open sidebar
ift
NIFTy
Commits
4fae9924
Commit
4fae9924
authored
Mar 13, 2019
by
Philipp Arras
Browse files
Options
Browse Files
Download
Email Patches
Plain Diff
Add NFFTOperator
parent
9f8bd423
Pipeline
#45187
passed with stages
in 8 minutes and 6 seconds
Changes
1
Pipelines
1
Hide whitespace changes
Inline
Sidebyside
Showing
1 changed file
with
73 additions
and
0 deletions
+73
0
nifty5/library/nfft.py
nifty5/library/nfft.py
+73
0
No files found.
nifty5/library/nfft.py
0 → 100644
View file @
4fae9924
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# Copyright(C) 20182019 MaxPlanckSociety
#
# Resolve is being developed at the MaxPlanckInstitut fuer Astrophysik.
import
numpy
as
np
import
nifty5
as
ift
class
NFFTOperator
(
ift
.
LinearOperator
):
"""Performs a nonequidistant Fourier transform, i.e. a Fourier transform
followed by a degridding operation.
Parameters

domain : RGSpace
Domain of the operator. It has to be twodimensional and have shape
`(2N, 2N)`. The coordinates of the lower left pixel of the dirty image
are `(N,N)`, and of the upper right pixel `(N1,N1)`.
uv : numpy.ndarray
2D numpy array of type float64 and shape (M,2), where M is the number
of measurements. uv[i,0] and uv[i,1] contain the u and v coordinates
of measurement #i, respectively. All coordinates must lie in the range
`[0.5; 0,5[`.
"""
def
__init__
(
self
,
domain
,
uv
):
from
pynfft.nfft
import
NFFT
npix
=
domain
.
shape
[
0
]
assert
npix
==
domain
.
shape
[
1
]
assert
len
(
domain
.
shape
)
==
2
assert
type
(
npix
)
==
int
,
"npix must be integer"
assert
npix
>
0
and
(
npix
%
2
)
==
0
,
"npix must be an even, positive integer"
assert
isinstance
(
uv
,
np
.
ndarray
),
"uv must be a Numpy array"
assert
uv
.
dtype
==
np
.
float64
,
"uv must be an array of float64"
assert
uv
.
ndim
==
2
,
"uv must be a 2D array"
assert
uv
.
shape
[
0
]
>
0
,
"at least one point needed"
assert
uv
.
shape
[
1
]
==
2
,
"the second dimension of uv must be 2"
assert
np
.
all
(
uv
>=

0.5
)
and
np
.
all
(
uv
<=
0.5
),
\
"all coordinates must lie between 0.5 and 0.5"
self
.
_domain
=
ift
.
DomainTuple
.
make
(
domain
)
self
.
_target
=
ift
.
DomainTuple
.
make
(
ift
.
UnstructuredDomain
(
uv
.
shape
[
0
]))
self
.
_capability
=
self
.
TIMES

self
.
ADJOINT_TIMES
self
.
npt
=
uv
.
shape
[
0
]
self
.
plan
=
NFFT
(
self
.
domain
.
shape
,
self
.
npt
,
m
=
6
)
self
.
plan
.
x
=
uv
self
.
plan
.
precompute
()
def
apply
(
self
,
x
,
mode
):
self
.
_check_input
(
x
,
mode
)
if
mode
==
self
.
TIMES
:
self
.
plan
.
f_hat
=
x
.
to_global_data
()
res
=
self
.
plan
.
trafo
().
copy
()
else
:
self
.
plan
.
f
=
x
.
to_global_data
()
res
=
self
.
plan
.
adjoint
().
copy
()
return
ift
.
Field
.
from_global_data
(
self
.
_tgt
(
mode
),
res
)
Write
Preview
Markdown
is supported
0%
Try again
or
attach a new file
Attach a file
Cancel
You are about to add
0
people
to the discussion. Proceed with caution.
Finish editing this message first!
Cancel
Please
register
or
sign in
to comment