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ms.putdata - Function
1.3.1 Write new values into the measurement set
This function allows you to write values from casapy variables back into the measurement set table. The main difference between this and directly accessing the table using the table tool is that this function writes data to the selected measurement set.
Unlike the getdata function you can only put items that correspond to actual table columns. You cannot change the data shape either so that the number of correlations, channels and rows (or intereferometers/time slots) must match the values in the selected measurement set. If the values were obtained using the getdata function with ifraxis argument set to True, then any default values added to fill in missing intereferometer/timeslots pairs will be ignored when writing the modified values back using this function.
The measurement set has to be opened for read/write access to be able to use this function.
You need to call selectinit before calling this function. If you haven’t then selectinit will be called for you with default arguments.
Items prefixed with either; corrected, model, residual or obs_residual and the imaging_weight item are not available unless your measurement set has been processed either with the imager or calibrator tools.
Record with items and their new values
rec = ms.getdata(["weight","data"])
rec[’weight’][:,:] = 1
meanrec = Numeric.average(rec[’data’],axis=None)
print "Mean data value = ", meanrec
rec[’data’][:,:,:] -= meanrec
This example selects all the data from the measurement set where
the value in the DATA_DESC_ID column is zero. This
corresponds to a particular spectral window and polarization
setup. Note that the measurement set was opened for writing as
well as reading. The third line reads all the weights and the
data into the casapy variable rec. The weights are set
to one. The more obscure syntax is used as typing
rec[’weight’] = 1 will not preserve the shape of the weight
array. The data then has its mean subtracted from
it. The average function is defined in Numeric module. Finally the data
is written back into the measurement set table. (NOTE: normally
one should not modify the raw data column. Such adjustments are more
appropriate for the corrected_data column, if it exists.)
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