1 #   Tests the Meqtree LMRaDec and LMN nodes
   2 
   3 # Copyright: The MeqTree Foundation
   4 
   5 # standard preamble
   6 from Timba.TDL import *
   7 from Timba.Meq import meq
   8 from Timba.Meq import meqds
   9 
  10 # Timba.TDL.Settings.forest_state is a standard TDL name.
  11 # This is a record passed to Set.Forest.State.
  12 Settings.forest_state.cache_policy = 100;
  13 
  14 def _define_forest (ns):
  15   """define_forest() is a standard TDL name.  """;
  16 # set up a sequence of nodes for testing of the LMRaDec node
  17 
  18 # first define a field centre RA and DEC (in radians)
  19   ra = 1.0
  20   dec = 1.0
  21   ns.ra0 << Meq.Parm(ra,node_groups='Parm')
  22   ns.dec0 << Meq.Parm(dec,node_groups='Parm')
  23 
  24 # then create a MeqComposer containing the field centre 
  25 # RA and DEC as children
  26   ns.RADec0 <<Meq.Composer(ns.ra0, ns.dec0)
  27 
  28 # then define an L,M location (in radians) with respect to
  29 # the field centre
  30   L_pos = -0.1   # radians
  31   M_pos =  0.5   # radians
  32   ns.l_pos << Meq.Parm(L_pos,node_groups='Parm')
  33   ns.m_pos << Meq.Parm(M_pos,node_groups='Parm')
  34 
  35 # create a  MeqComposer containing L_pos and M_pos as children
  36   ns.LM <<Meq.Composer(ns.l_pos, ns.m_pos)
  37 
  38 # we should now be able to create an LMRaDec node with the 
  39 # field centre RA and DEC and the L and M offsets as 
  40 # children. This node gives as output the RA and DEC 
  41 # corresponding to the specified L,M offset.
  42   ns.LMRaDec << Meq.LMRaDec(radec_0=ns.RADec0, lm=ns.LM)
  43 
  44 # Finally, as a check: convert the resulting RA and DEC back 
  45 # to L,M with respect to the field centre. This is done by
  46 # creating an LMN node which has the field centre 
  47 # RA and DEC and the offset RA and DEC as children.
  48   ns.LMN << Meq.LMN(ns.RADec0, ns.LMRaDec)
  49 
  50 def _test_forest (mqs,parent):
  51   """test_forest() is a standard TDL name.""";
  52 
  53 ####
  54 # any old time and frequency domain will do
  55 # time - cover one day
  56   t0 = 0.01;
  57   t1 = 86400.01;
  58 
  59 # any old frequency
  60   f1 =  299792458.0;
  61   f0 = 0.9*f1;
  62 
  63 ####
  64 # Make cells array - a period of one day divided into 120 segments
  65 
  66   cells = meq.cells(meq.domain(f0,f1,t0,t1),num_freq=1,num_time=120);
  67 
  68 # define request
  69   request = meq.request(cells,rqtype='e1')
  70 
  71 # execute request
  72   a = mqs.meq('Node.Execute',record(name='LMN',request=request),
  73               wait=True);
  74 
  75 # The following is the testing branch, executed when the script is run directly
  76 # via 'python script.py'
  77 if __name__ == '__main__':
  78   Timba.TDL._dbg.set_verbose(5);
  79   ns = NodeScope();
  80   _define_forest(ns);
  81   # resolves nodes
  82   ns.Resolve();