casa6

from taskinit import *

import numpy as np

​

def CheckUVWForNan(ms='', fix=False):

    """

    script to check for NaN in uvw

    if fix is true it will flag the row with nan data

    and replace the uvw with 0

    you can see how to do that to other columns too

    """

    tb.open(ms, nomodify=(not fix))

    uvw=tb.getcol('UVW')

    flg=tb.getcol('FLAG_ROW')

    nanoo=np.isnan(uvw)

    for k in range(nanoo.shape[1]):

      if(nanoo[0,k] or nanoo[1,k] or nanoo[2,k]):

          print 'row=', k

          uvw[0,k]=0

          uvw[1,k]=0

          uvw[2,k]=0

          flg[k]=True

    if(fix):

        tb.putcol('UVW', uvw)

        tb.putcol('FLAG_ROW', flg)

    tb.done()

##########################################

def CheckColsForNan(msname='',fix=False,colnames=[],timeinterval=1000):

    """

    Check for NaNs in specified columns of the MS.

    ms : Name of MS. 

    fix : False/True : If True, 

                             For data/corrected_data, set the corresponding value to zero and

                                       flag to True in the FLAG column

                             For weight, weight_spectrum, set the corresponding value to zero

                             For all other columns, do not fix/change anything.

    colnames : ['data','weight'] :  MS Column names on which to check for NaNs

    timeinterval : 1000 : timerange in seconds, to decide chunk sizes while iterating 

                                   through the MS (remember, chunks of this size are read 

                                   into python).

    Alternate (recommended) way to flag NaNs from data columns :

        flagdata(vis=ms, mode='clip')    

    """

    ms = casac.ms()

​

    # Open the MS with the intent to modify it.

    ms.open(msname,nomodify=(not fix));

​

    # Iterate through the dataset in chunks defined by

    # a time interval of 1000 seconds.

    ms.iterinit(interval=timeinterval);

    ## Initialize the ms iterator

    ms.iterorigin();

    ## Iterate until the end of the MS is reached.

    counter=0;

    moretodo=True;

    while moretodo: 

        counter=counter+1;

        print 'Chunk : ', counter 

​