[HTCondor-users] Empty __JOIN__.sub file when creating dag with API

[mtwest2718 <mtwest2718@xxxxxxxxxxxxxx>]

I am creating a dag with the HTCondor python API that nominally consists of two layers.

1. Multiple independent sampling jobs that generate CSV files
   
2. Two trace plotting jobs using the same script with with different input arguments
   

    trace_layer = sample_layer.child_layer(

        name = 'trace', submit_description = trace_sub,

        vars = trace_vars)

When I call dags.write_dag(), this function also generates an empty __JOIN__.sub file and the dag file looks like this:

# BEGIN META

# END META

# BEGIN NODES AND EDGES

JOB sample:0 sample.sub

VARS sample:0 seed="670487" iters="1000" threads="1"

JOB sample:1 sample.sub

VARS sample:1 seed="116739" iters="1000" threads="1"

PARENT sample:0 sample:1 CHILD __JOIN__:0

PARENT __JOIN__:0 CHILD trace:0 trace:1

JOB trace:0 trace.sub

VARS trace:0 files_list="samples_0.csv samples_1.csv" est_type="area"

JOB trace:1 trace.sub

VARS trace:1 files_list="samples_0.csv samples_1.csv" est_type="func"

JOB __JOIN__:0 __JOIN__.sub NOOP

# END NODES AND EDGES

Is this what is supposed to happen or am I just missing some extra arguments when specifying child layers?

Cheers,

Matt