MeqLMRaDec.py

#   Tests the Meqtree LMRaDec and LMN nodes# Copyright: The MeqTree Foundation# standard preamblefrom Timba.TDL import *from Timba.Meq import meqfrom Timba.Meq import meqds# Timba.TDL.Settings.forest_state is a standard TDL name.# This is a record passed to Set.Forest.State.Settings.forest_state.cache_policy = 100;def _define_forest (ns):  """define_forest() is a standard TDL name.  """;# set up a sequence of nodes for testing of the LMRaDec node# first define a field centre RA and DEC (in radians)  ra = 1.0  dec = 1.0  ns.ra0 << Meq.Parm(ra,node_groups='Parm')  ns.dec0 << Meq.Parm(dec,node_groups='Parm')# then create a MeqComposer containing the field centre # RA and DEC as children  ns.RADec0 <<Meq.Composer(ns.ra0, ns.dec0)# then define an L,M location (in radians) with respect to# the field centre  L_pos = -0.1   # radians  M_pos =  0.5   # radians  ns.l_pos << Meq.Parm(L_pos,node_groups='Parm')  ns.m_pos << Meq.Parm(M_pos,node_groups='Parm')# create a  MeqComposer containing L_pos and M_pos as children  ns.LM <<Meq.Composer(ns.l_pos, ns.m_pos)# we should now be able to create an LMRaDec node with the # field centre RA and DEC and the L and M offsets as # children. This node gives as output the RA and DEC # corresponding to the specified L,M offset.  ns.LMRaDec << Meq.LMRaDec(radec_0=ns.RADec0, lm=ns.LM)# Finally, as a check: convert the resulting RA and DEC back # to L,M with respect to the field centre. This is done by# creating an LMN node which has the field centre # RA and DEC and the offset RA and DEC as children.  ns.LMN << Meq.LMN(ns.RADec0, ns.LMRaDec)def _test_forest (mqs,parent):  """test_forest() is a standard TDL name.""";##### any old time and frequency domain will do# time - cover one day  t0 = 0.01;  t1 = 86400.01;# any old frequency  f1 =  299792458.0;  f0 = 0.9*f1;##### Make cells array - a period of one day divided into 120 segments  cells = meq.cells(meq.domain(f0,f1,t0,t1),num_freq=1,num_time=120);# define request  request = meq.request(cells,rqtype='e1')# execute request  a = mqs.meq('Node.Execute',record(name='LMN',request=request),              wait=True);# The following is the testing branch, executed when the script is run directly# via 'python script.py'if __name__ == '__main__':  Timba.TDL._dbg.set_verbose(5);  ns = NodeScope();  _define_forest(ns);  # resolves nodes  ns.Resolve();```