MeqLST.py

# A Python TDL script to test the LST nodefrom Timba.TDL import *from Timba.Meq import meqfrom Timba.Meq import meqds# setup a bookmark for display of results with a 'Result Plotter'Settings.forest_state = record(bookmarks=[  record(name='LST',page=[    record(udi="/node/LST",viewer="Result Plotter",pos=(0,0)),    record(udi="/node/LST1",viewer="Result Plotter",pos=(1,0))])]);# 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. When a forest script is  loaded by, e.g., the browser, this method is automatically called to  define the forest. The 'ns' argument is a NodeScope object in which  the forest is to be defined, usually this is simply the global scope.  """;# ITRF station positions for one of the VLA telescopes# (units are metres)  X_pos = -1597262.96  Y_pos = -5043205.54  Z_pos = 3554901.34  ns.x_pos << Meq.Parm(X_pos,node_groups='Parm')  ns.y_pos << Meq.Parm(Y_pos,node_groups='Parm')  ns.z_pos << Meq.Parm(Z_pos,node_groups='Parm')# create a  MeqComposer containing X_pos, Y_pos, Z_pos children  ns.XYZ <<Meq.Composer(ns.x_pos, ns.y_pos, ns.z_pos)# we should be able to create an LST node with X,Y,Z station positions  ns.LST << Meq.LST(xyz=ns.XYZ)# we should also be able to create an LST node with an Observatory name  ns.LST1 << Meq.LST(observatory='VLA')# create a ReqSeq node to call the two LST nodes  ns.reqseq <<Meq.ReqSeq(ns.LST,ns.LST1)def _test_forest (mqs,parent):  """test_forest() is a standard TDL name. When a forest script is  loaded by, e.g., the browser, and the "test" option is set to true,  this method is automatically called after define_forest() to run a  test on the forest. The 'mqs' argument is a meqserver proxy object.  """;##### time and frequency domain# time - cover one day  t0 = 0.01;  t1 = 86400.01;# any old frequency  f1 =  299792458.0;  f0 = 0.9*f1;##### Make cells array - we will compute Azimuth and Elevation over 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='reqseq',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();```