Taking the outputs of two subworkchains when these are the same

General Usage
1

Hi everyone.

I have a quick question. Imagine that I use a workchain that submits two subworkchains. I want to retrieve the outputs of the two subworkchains via the big workchain. Hence, I have to use:

self.out_many(
self.exposed_outputs(self.ctx.subworkchain_node_1, subworkchain1)
)
self.out_many(
self.exposed_outputs(self.ctx.subworkchain_node_2 ,subworkchain2)
)

Now, Imagine that unfortunately, subworkchain1 and subworkchain2 have an output with the same name, ‘output_parameters’. I guess that this is a conflict because when writing something like bigworkchain_node.outputs.output_parameters, we have no way to distinguish which one we want, the one corresponding to subworkchain1 or subworkchain2.

Now my question is, how can I solve this issue in a smart way? Is there a way to rename certain outputs of the subworkchains? I am looking forward to read your ideas :slight_smile:

Thanks in advance

Jaime

2

Hi Jaime,

the expose_outputs and exposed_outputs methods have the namespace argument, which addresses the “issue” that you mentioned. In your example, you could do the following:

class BigWorkChain(WorkChain):
    @classmethod
    def define(cls, spec):
        super().define(spec)
        # outline etc.
        spec.expose_outputs(subworkchain1, namespace='sub_1')
        spec.expose_outputs(subworkchain2, namespace='sub_2')

    def results(self):
        self.out_many(
        self.exposed_outputs(self.ctx.subworkchain_node_1, subworkchain1, namespace='sub_1')
        )
        self.out_many(
        self.exposed_outputs(self.ctx.subworkchain_node_2 ,subworkchain2, namespace='sub_2')
        )

Assuming that both WorkChains have an output namespace called output_parameters, you can access them via:

result.outputs.sub_1.output_parameters

result.outputs.sub_2.output_parameters

The following section in the documentation explains this in more detail: Usage — AiiDA 2.5.1.post0 documentation

Hope this helps!

3

Hi

The solution you provide is perfect for what I am looking for

Tanks a lot!

Jaime