Assigning job priority

You might want to control the order in which your FireWorks are run. Setting job priority is simple. A few notes:

• You can assign any numerical value to the priority, including negative numbers and decimals. Higher priorities are run first.

• FireWorks with any value of priority will be run before jobs without a priority defined. If two FireWorks have the same priority, one of those jobs will be chosen randomly (you can also choose FIFO and FILO ordering for equal-priority FireWorks via the FW config).

• You can launch specific fireworks from the command line via rlaunch singleshot -f FW_ID or qlaunch -r singleshot -f FW_ID.

Set job priority using the command line after adding FWs

If you would like to set the priority of a Firework after you have already entered it into the LaunchPad, you can do so via the command:

lpad set_priority <PRIORITY> -i <FW_IDS>

where <FW_IDS> is the numerical id of the Firework you want to set the priority of (or a list of comma-separated ids), and <PRIORITY> is the priority to assign.

Instead of specifying ids, you can also specify a name (-n), a state (-s), or a custom query (-q). The full command is thus:

lpad set_priority <PRIORITY> [-i FW_IDS] [-n NAME] [-s STATE] [-q QUERY]

Refer to the documentation (lpad set_priority -h) for more information.

Set job priority when creating FireWorks

To set job priority, simply set a key named _priority in your Firework spec to your desired priority. FireWorks will automatically prioritize jobs based on their value of this key.

Example 1: Prioritize one workflow over another

Imagine we have two workflows, A and B, with two steps each (1 and 2). We want to run workflow A in its entirety before beginning workflow B. Our execution should follow the blue arrow:

Let’s examine how we can set up such an execution model.

1. Move to the A_then_B subdirectory of the priority tutorial directory in your installation directory:

   cd <INSTALL_DIR>/fw_tutorials/priority/A_then_B
   

2. Look inside the files wfA.yaml and wfB.yaml. You’ll notice that the _priority key for both steps of wfA.yaml is set to 2, whereas the corresponding values for the steps of wfB.yaml are only 1. This means that workflow A will execute in its entirety before starting workflow B.

3. Add and run the FireWorks to confirm:

   lpad reset
   lpad add *.yaml
   rlaunch -s rapidfire
   

4. You should have noticed text printed to the Terminal in the following order:

   Task A-1
   Task A-2
   Task B-1
   Task B-2
   

Example 2: A breadth-first workflow

Let’s now try another execution order: A-1, B-1, B-2, A-2.

1. Move to the breadthfirst subdirectory of the priority tutorial directory in your installation directory:

   cd <INSTALL_DIR>/fw_tutorials/priority/breadthfirst
   

2. Look inside the files wfA.yaml and wfB.yaml. You’ll notice that this time, the _priority key is highest for step A-1 and lowest for step A-2, corresponding to our desired execution order.

3. Add and run the FireWorks to confirm:

   lpad reset
   lpad add *.yaml
   rlaunch -s rapidfire
   

4. You should have noticed text printed to the Terminal in the following order:

   Task A-1
   Task B-1
   Task B-2
   Task A-2