how to set q_point to 0.0 0.0 0.0 in quantumespresso.ph.x?

[Witty Yonng]

Hi all,

I want to calculate effective charge using quantumespresso.ph.x and can not set q_points to zero  [0.0, 0.0, 0.0], because it always raise error. Could you give me an example about how to set q_points to zero?

Thanks,

Best,

Witty

[Jusong Yu]

Hi Witty,

Can you elaborate a bit on which error was raised? 

The qpoints can be set by creating an orm.KpointsData and pass to PhBaseWorkflow. 

Here is how I put it in my workflow (be careful that the shape of qpoints_list depends on the dimension of your system[1]):

```

qpoints_list = [[0.0, 0.0, 0.0], [0.5, 0.5, 0.5]]

qpoints = orm.KpointsData()
qpoints.set_cell_from_structure(self.ctx.structure)
qpoints.set_kpoints(qpoints_list)

inputs = {
                    "code": <ph_code>,
                    "qpoints": qpoints,
                    "parameters": orm.Dict(dict=<.ph_parameters>),
                    "metadata": {
                        "options": <ph_options>,
                    },
                },

self.submit(PwBaseWorkflow, **inputs)

```

I hope it helps.

Best,

Jason

[1]: https://aiida.readthedocs.io/projects/aiida-core/en/latest/reference/apidoc/aiida.orm.nodes.data.array.html#aiida.orm.nodes.data.array.kpoints.KpointsData.set_kpoints