Condor DAG file - parents with many children. Is it legal to have the parents of a child denoted on multiple lines instead of one?

Question

Here's a simple tree of what I have:

     A     B
      \   /
        C

A and B are the parent processes and C can only run after A and B have finished. Normally, the DAG file would look like so:

JOB A a.condor
JOB B b.condor
JOB C c.condor
PARENT A, B CHILD C

I was wondering if anyone knows if the following would also work:

JOB A a.condor
JOB B b.condor
JOB C c.condor
PARENT A CHILD C
PARENT B CHILD C

I've looked through the Condor DAG documentation, but it's not much help.

Thanks!

Answer 1

Yes, both of your examples are valid and equivalent. You can make as many PARENT/CHILD declarations as you want—even with the same node referenced in more than one declaration—and as long as there are no cycles, DAGMan will use them all.

Here is a support ticket with the Condor developers to clarify this point in the documentation.

Answer 2

The DAG parser is pretty stupid, so the line "PARENT A, B Child C" will cause a problem when DAGMan tries to find a node named "A,". i.e., you should drop the comma.