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(0)            # Get spw 0 data

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)