casa6

from __future__ import absolute_import

​

import numpy as np

from numpy import sqrt, cos, sin

import scipy.special as spspec

import scipy.signal

import scipy.interpolate

from scipy import optimize

​

from casatasks.private.casa_transition import is_CASA6

if is_CASA6:

    from casatools import quanta

    from casatasks import casalog

else:

    from taskinit import casalog, qatool

​

    quanta = qatool

​

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

### Prediction of theoretical beam size

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

class TheoreticalBeam:

    """

    The class to derive the theoretical beam size of an image.

​

    Example:

    bu = sdbeamutil.TheoreticalBeam()

    # set imaging, antenna, and pointing informations

    bu.set_antenna('12m',blockage='0.75m',taper=10)

    bu.set_sampling(['12arcsec','12arcsec'])

    bu.set_image_param('5arcsec', '115GHz','SF', 6, -1, -1, -1)

    # print summary of setup to logger

    bu.summary()

    # get theoretical beam size of an image.

    beam = bu.get_beamsize_image()

    """

    def __init__(self):

        self.is_antenna_set = False

        self.is_kernel_set = False

        self.is_sampling_set = False

        self.antenna_diam_m = -1.

        self.antenna_block_m = 0.0

        self.taper = 10

        self.ref_freq = -1.

        self.kernel_type=""

        self.kernel_param={}

        self.pa = "0.0deg"

        self.sampling_arcsec = []

        self.cell_arcsec = []

​

    def __to_arcsec_list(self, angle):

        """return a list of angles in arcsec (value only without unit)"""

        if type(angle) not in [list, tuple, np.ndarray]:

            angle = [angle]

        return [self.__to_arcsec(val) for val in angle]

​

    def __to_arcsec(self, angle):

        """convert angle to arcsec and return the value without unit."""

        my_qa = quanta( )

        if my_qa.isangle(angle):

            return my_qa.getvalue(my_qa.convert(angle, "arcsec"))[0]

        elif my_qa.getunit(angle)=='': return float(angle)