sdmpy 1.3

Python for ALMA/VLA Science Data Model

sdmpy -- P. Demorest, 2015/03

Simple classes for reading VLA/ALMA Science Data Model (SDM) XML
files. The structure of the SDM is a set of tables, which contain
rows of data. The main goal of this is to have a straightforward,
relatively dependency-free way of doing simple or low-level stuff with
SDMs (e.g., for situations where invoking CASA is unnecessary).

Here is a short ipython session showing a example usage:

In [1]: import sdmpy

In [2]: s = sdmpy.SDM('15A-105_sb30463808_1.57082.53091797454')

In [3]: s.tables
Out[3]:
['SpectralWindow',
'CalData',
'Antenna',
'Subscan',
'SwitchCycle',
'Polarization',
'Source',
'State',
'Station',
'Main',
'Flag',
'ExecBlock',
'SBSummary',
'ConfigDescription',
'Receiver',
'Processor',
'CorrelatorMode',
'Feed',
'PointingModel',
'Field',
'Scan',
'CalDevice',
'Weather',
'CalReduction',
'DataDescription']

In [4]: s['Field'][0].keys
Out[4]:
['code',
'referenceDir',
'phaseDir',
'sourceId',
'delayDir',
'fieldName',
'time',
'fieldId',
'numPoly']

In [5]: s['Field'][0].fieldName
Out[5]: 'J1728+0427'

In [6]: for row in s['Field']: print row.fieldName
J1728+0427
J1713+0747
J1924-2914
J1909-3744
1411+522=3C295

In [7]: len(s['Main'])
Out[7]: 24


sdmpy also contains a parser for BDF (Binary Data Format) files, which contain
the actual visibility data. Note that this has been developed mainly for
VLA/WIDAR data and is likely not complete for use with ALMA data. Example
usage (see docstrings for more info):

In [1]: import sdmpy

In [2]: b = sdmpy.BDF('uid____evla_bdf_1433189755525')

In [3]: b.numAntenna
Out[3]: 25

In [4]: b.numBaseline
Out[4]: 300

In [5]: b.numIntegration
Out[5]: 180

In [6]: b.basebands
Out[6]: ['AC_8BIT', 'BD_8BIT']

In [7]: i = b.get_integration(17) # Get integration number 17

In [8]: d = i.get_data('AC_8BIT',0) # Get spw 0 from AC IF

In [9]: d.shape
Out[9]: (300, 1, 64, 4)

In [10]: d[10,0,:,0]
Out[10]:
array([ -1.92527496e-03+0.00236825j, -1.01333787e-03-0.0019273j ,
3.88602726e-04-0.00326904j, 3.37082194e-04+0.0035117j ,
4.74026240e-03-0.00303986j, -1.39878283e-03+0.00315546j,
4.75925812e-03+0.00384983j, -6.46819070e-04-0.00230185j,
1.04035577e-03-0.0033494j , 4.77438327e-04+0.00407107j,
-7.42492499e-03-0.00551728j, -4.23104153e-04-0.00136438j,
-1.09272427e-04-0.00189404j, 2.70528137e-04+0.00265754j,
9.03953623e-04+0.00172536j, -2.13428610e-03+0.00210991j,
4.50677879e-04+0.00092774j, 2.75413692e-03+0.00105019j,
2.04323884e-03+0.00331562j, -4.14338522e-03+0.00393523j,
2.90520466e-03-0.00068069j, -7.84504786e-03+0.0031926j ,
-1.59289513e-03-0.00068654j, -8.57894833e-04+0.00268888j,
-4.27102018e-03+0.00065515j, 3.69449146e-03-0.00241908j,
4.95729037e-04+0.00161663j, -1.60046294e-03-0.00291464j,
-2.17019930e-03-0.00133767j, -3.01234191e-04-0.00817809j,
5.38951717e-05-0.00192556j, -5.56168333e-03-0.00130252j,
5.06524229e-05+0.00059094j, 1.00876275e-03+0.00976392j,
-6.54946594e-03+0.00503897j, -2.47276877e-03-0.0019854j ,
3.56894545e-03+0.00648416j, -1.66386040e-03-0.00040906j,
3.25945253e-03-0.0011268j , 6.37905393e-03+0.00060488j,
2.66728364e-03-0.00056195j, 2.84236716e-03+0.00086546j,
3.23694502e-03+0.00111199j, 6.35888521e-03+0.00346222j,
-3.01071745e-03+0.0015606j , 6.97700772e-04+0.00021654j,
-5.21393435e-04+0.00208696j, 2.45397002e-03-0.00393461j,
-1.13227195e-03+0.00167564j, -2.68122321e-03-0.00271649j,
-1.96605665e-03-0.00489836j, 2.49449024e-03+0.0007483j ,
-7.28207640e-04+0.00322795j, -3.14944983e-03-0.00022846j,
9.21148807e-04+0.00533055j, -9.83621459e-04+0.00440285j,
-4.31790622e-03-0.00243727j, -4.21724096e-03-0.00223194j,
1.09594746e-03+0.00397917j, -2.94885552e-03-0.00085458j,
7.17548071e-04-0.00044755j, -2.99423118e-05-0.00164009j,
1.18584884e-03+0.00028139j, -5.73034631e-04+0.00078536j], dtype=complex64)