run_relax should be used for get pw-parameters

[unkcpz]

fixes #318

@superstar54 We had a discussion about this, seems I didn't change these parts of code back to normal.

[superstar54]

There is a logic bug here.

If we run scf only, the pw_parameters will be None. Thus, the following code will raise a error.

    energy_cutoff_wfc = round(pw_parameters["SYSTEM"]["ecutwfc"])

Since we use parameters["relax_type"]=RealxType.NONE to run the scf calculation. So, no matter what kind of calculations we choose, there should always have a relax calculation. Therefore, line 33

run_relax = builder_parameters.get("relax_type") != "none"

needs change to:

run_relax = True

In file steps.py, line 871,

        # skip relax sub-workflow only when RelaxType is NONE and has property calculated.
        if RelaxType(parameters["relax_type"]) is RelaxType.NONE and (
            parameters["run_bands"] or parameters["run_pdos"]
        ):
            builder.pop("relax")

The above code should be removed, to make sure there is a relax calculation.

@unkcpz What do you think?

[unkcpz]

Hi @superstar54, the issue is more complex. Please check the comment I add to the code. The problem all comes from us running SCF which is a non-relax calculation using the PwRelaxWorkChain.

[superstar54]

@unkcpz You are right. One quick solution would be:
Change

    run_relax = builder_parameters.get("relax_type") != "none"
    run_bands = builder_parameters.get("run_bands")
    run_pdos = builder_parameters.get("run_pdos")

to:

    run_bands = builder_parameters.get("run_bands")
    run_pdos = builder_parameters.get("run_pdos")
    run_relax = not (builder_parameters.get("relax_type") == "none" & (run_relax or run_pdos))

[unkcpz]

@superstar54 thanks! I implement it by check if the relax port is in the workchain, please see my implementation, what you suggest has the advantage that the change all kept in one place, but to me, it is still very mind-binding.

    # The run_relax variable is not same as if statement below.
    # the "relax" port is poped out to skip the real relaxiation
    # which is not the case of SCF, we use the relax workchain but with
    # relax_type set to none as SCF calculation.
    if "relax" in qeapp_wc.inputs:
        pw_parameters = qeapp_wc.inputs.relax.base.pw.parameters.get_dict()
        if scf_kpoints_distance is None:
            scf_kpoints_distance = qeapp_wc.inputs.relax.base.kpoints_distance.value

I run two tests, one SCF and one relax=none + property. All works fine.

[superstar54]

LGTM!

[unkcpz]

@superstar54 thanks millions!