Skip to content
Snippets Groups Projects
Commit a78c006e authored by Wouter Klijn's avatar Wouter Klijn
Browse files

Task #3480: comment of toplevel recipe

parent 8b41a315
No related branches found
No related tags found
No related merge requests found
...@@ -20,43 +20,70 @@ from lofarpipe.support.utilities import patch_parset ...@@ -20,43 +20,70 @@ from lofarpipe.support.utilities import patch_parset
class msss_imager_pipeline(control): class msss_imager_pipeline(control):
""" """
The MSSS imager pipeline can be used to generate MSSS images. The Automatic MSSS imager pipeline is used to generate MSSS images and find
sources in the generated images. Generated images and lists of found sources
MSSS images are compiled from a number of so-called slices. Each slice are complemented with meta data and thus ready for consumption by the
Long Term Storage (LTA)
*subband groups*
The imager_pipeline is able to generate images on the frequency range of
LOFAR in parallel. Combining the frequency subbands together in so called
subbandgroups. Each subband group will result in an image and sourcelist,
(typically 8, because ten subband groups are combined).
*Time Slices*
MSSS images are compiled from a number of so-called (time) slices. Each slice
comprises a short (approx. 10 min) observation of a field (an area on the comprises a short (approx. 10 min) observation of a field (an area on the
sky) containing 80 subbands. The number of slices will be different for LBA sky) containing typically 80 subbands. The number of slices will be
observations (typically 9) and HBA observations (typically 2), due to different for LBA observations (typically 9) and HBA observations
differences in sensitivity. (typically 2), due to differences in sensitivity.
One MSSS observation will produce a number of images (typically 8), one for
each so-called subband-group (SBG). Each SBG consists of the same number
of consecutive subbands (typically 10).
Each image will be compiled on a different cluster node to balance the Each image will be compiled on a different cluster node to balance the
processing load. The input- and output- files and locations are determined processing load. The input- and output- files and locations are determined
by the scheduler and specified in the parset-file. by the scheduler and specified in the parset-file.
*steps*
This pipeline performs the following operations:
1. Prepare Phase: Copy the preprocessed MS's from the different compute
nodes to the nodes where the images will be compiled (the prepare phase).
Combine the subbands in subband groups, concattenate the timeslice in a
single large measurement set and perform flagging, RFI and bad station
exclusion.
2. Create db: Generate a local sky model (LSM) from the global sky model
(GSM) for the sources that are in the field-of-view (FoV). The LSM
is stored as sourcedb.
In step 3 calibration of the measurement sets is performed on these
sources and in step 4 to create a mask for the awimager. The calibration
solution will be placed in an instrument table/db also created in this
step.
3. BBS: Calibrate the measurement set with the sourcedb from the gsm.
In later iterations sourced found in the created images will be added
to this list. Resulting in a selfcalibration cycle.
4. Awimager: The combined measurement sets are now imaged. The imaging
is performed using a mask: The sources in the sourcedb are used to create
an casa image masking known sources. Together with the measurement set
an image is created.
5. Sourcefinding: The images created in step 4 are fed to pyBDSM to find and
describe sources. In multiple itterations substracting the found sources,
all sources are collectedin a sourcelist.
I. The sources found in step 5 are fed back into step 2. This allows the
Measurement sets to be calibrated with sources currently found in the
image. This loop will continue until convergence (3 times for the time
being).
6. Finalize: Meta data with regards to the input, computations performed and
results are collected an added to the casa image. The images created are
converted from casa to HDF5 and copied to the correct output location.
7. Export meta data: An outputfile with meta data is generated ready for
consumption by the LTA and/or the LOFAR framework
Per subband-group, the following output products will be delivered:
a. An image
b. A source list
c. (Calibration solutions and corrected visibilities)
This pipeline will perform the following operations:
- Copy the preprocessed MS's from the different compute nodes to the nodes
where the images will be compiled (the prepare phase).
- Flag the long baselines using DPPP
- Concatenate the MS's of the different slices as one virtual MS for
imaging.
- Generate a local sky model (LSM) from the global sky model (GSM) for the
sources that are in the field-of-view (FoV).
- Repeat until convergence (3 times for the time being):
- Per slice: solve and correct for phases using BBS with TEC enabled
- Run the awimager.
- Run the source finder (PyBDSM) and update the local sky model (LSM).
Per subband-group, the following output products will be delivered:
- Calibration solutions and corrected visibilities
- An image
- A source list
""" """
def __init__(self): def __init__(self):
control.__init__(self) control.__init__(self)
self.parset = parameterset() self.parset = parameterset()
......
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment