def __init__(self, infiles):
self._separator = SBSeparator(infiles)
class sbseparator:
"""
The sbseparator class is defined to separate SIGNAL and IMAGE
sideband spectra observed by frequency-switching technique.
It also helps supressing emmission of IMAGE sideband.
*** WARNING *** THIS MODULE IS EXPERIMENTAL
Known issues:
- Frequencies of IMAGE sideband cannot be reconstructed from
information in scantable in sideband sparation. Frequency
setting of SIGNAL sideband is stored in output table for now.
Example:
# Create sideband separator instance whith 3 input data
sbsep = sbseparator(['test1.asap', 'test2.asap', 'test3.asap'])
# Set reference IFNO and tolerance to select data
sbsep.set_frequency(5, 30, frame='TOPO')
# Set direction tolerance to select data in unit of radian
sbsep.set_dirtol(1.e-5)
# Set rejection limit of solution
sbsep.set_limit(0.2)
# Solve image sideband as well
sbsep.set_both(True)
# Invoke sideband separation
sbsep.separate('testout.asap', overwrite = True)
"""
def __init__(self, infiles):
self._separator = SBSeparator(infiles)
def set_frequency(self, baseif, freqtol, frame=""):
"""
Set IFNO and frequency tolerance to select data to process.
Parameters:
- reference IFNO to process in the first table in the list
- frequency tolerance from reference IF to select data (string)
frame : frequency frame to select IF
"""
if type(freqtol) in (float, int):
freqtol = str(freqtol)
elif isinstance(freqtol, dict):
try:
freqtol = str(freqtol['value']) + freqtol['unit']
except:
raise ValueError, "Invalid frequency tolerance."
self._separator.set_freq(baseif, freqtol, frame)
def set_dirtol(self, dirtol=["2arcsec", "2arcsec"]):
"""
Set tolerance of direction to select data
"""
if isinstance(dirtol, str):
dirtol = [dirtol]
self._separator.set_dirtol(dirtol)
def set_shift(self, imageshift=[]):
"""
Set shift mode and channel shift of image band.
imageshift : a list of number of channels shifted in image
side band of each scantable.
If the shifts are not set, they are assumed to be
equal to those of signal side band, but in opposite
direction as usual by LO1 offsetting of DSB receivers.
"""
if not imageshift:
imageshift = []
self._separator.set_shift(imageshift)
@asaplog_post_dec
def set_both(self, flag=False):
"""
Resolve both image and signal sideband when True.
"""
self._separator.solve_both(flag)
if flag:
asaplog.push("Both signal and image sidebands will be solved and stored in separate tables.")
else:
asaplog.push("Only signal sideband will be solved and stored in an table.")
@asaplog_post_dec
def set_limit(self, threshold=0.2):
"""
Set rejection limit of solution.
"""
self._separator.set_limit(threshold)
@asaplog_post_dec
def set_solve_other(self, flag=False):
"""
Calculate spectra by subtracting the solution of the other sideband
when True.
"""
self._separator.subtract_other(flag)
if flag:
asaplog.push("Expert mode: solution are obtained by subtraction of the other sideband.")
def set_lo1(self, lo1, frame="TOPO", reftime=-1, refdir=""):
"""
Set LO1 frequency to calculate frequency of image sideband.
lo1 : LO1 frequency
frame : the frequency frame of LO1
reftime : the reference time used in frequency frame conversion.
refdir : the reference direction used in frequency frame conversion.
"""
self._separator.set_lo1(lo1, frame, reftime, refdir)
def set_lo1root(self, name):
"""
Set MS name which stores LO1 frequency of signal side band.
It is used to calculate frequency of image sideband.
name : MS name which contains 'ASDM_SPECTRALWINDOW' and
'ASDM_RECEIVER' tables.
"""
self._separator.set_lo1root(name)
@asaplog_post_dec
def separate(self, outname="", overwrite=False):
"""
Invoke sideband separation.
outname : a name of output scantable
overwrite : overwrite existing table
"""
out_default = "sbseparated.asap"
if len(outname) == 0:
outname = out_default
asaplog.post()
asaplog.push("The output file name is not specified.")
asaplog.push("Using default name '%s'" % outname)
asaplog.post("WARN")
if os.path.exists(outname):
if overwrite:
asaplog.push("removing the old file '%s'" % outname)
shutil.rmtree(outname)
else:
asaplog.post()
asaplog.push("Output file '%s' already exists." % outname)
asaplog.post("ERROR")
return False
self._separator.separate(outname)
