Task #3139: Helperclass WritableParmDB.py added with implementation

CEP/Pipeline/recipes/sip/helpers/WritableParmDB.py

+from __future__ import with_statement
 from lofar.parmdb import parmdb
+from argparse import ArgumentTypeError
+
+
+def list_stations(parmdb, pattern = ''):
+    """
+    Get a sorted list of all the station names, without prepending polarisation
+    Information,
+    Can be called with a path or an instantiated parmdb     
+    """
+    # validate input
+    if isinstance(parmdb, basestring):
+        # create a WritableParmDB
+        parmdb = WritableParmDB(parmdb)
+    elif not isinstance(parmdb, WritableParmDB):
+        raise ArgumentTypeError("list_stations can only be called with a string or an"
+                            "instantiated WritableParmDB")
+
+    raw_name_list = parmdb.getNames(parmnamepattern = pattern)
+    # The names are 'complex' split at the :
+    # and get the last index of the split. use set so they are unique.
+    # return the sorted list
+    return sorted(set(name.split(":")[-1] for name in raw_name_list))
+
+
 
 class WritableParmDB(parmdb):
     def __init__(self, name):
         super(WritableParmDB, self).__init__(name)
         self.name = name
 
+    def setValues(self, name, values, start_freq, freqstep, start_time, timestep):
+        """
+        Write values to the ParmDB.
+
+        Note that values should be a two dimenstional array with the first
+        index corresponding to time and the second to time (this is the same
+        as returned by ParmDB.getValues()).
+
+        Arguments:
+
+        name       -- Parameter name to write.
+        values     -- NumPy array of values to write.
+        start_freq -- Frequency at centre of first bin (Hz).
+        freqstep   -- Bin-to-bin frequency increment (Hz).
+        start_time -- Time at centre of first bin (MJD in seconds).
+        timestep   -- Bin-to-bin time increment (s).
+        
+        Version 1.0: usage of direct parmdb calls instead of subprocess and 
+            an executable
+        """
+
+        # Get the number of steps, both in time and freq
+        time_steps, freq_steps = values.shape
+        # remove the old entry
+        self.deleteValues(name)
+
+        self.addValues(name, values,
+                       start_freq,
+                       start_freq + freqstep * freq_steps,
+                       start_time,
+                       start_time + timestep * time_steps,
+                       False)
+