Radiation plugin: Fix checkpointing

[franzpoeschel]

Follow-up to #4387
Fix #4397

[PrometheusPi]

There seems to have been a crash in the CI with some clang compiler - I restarted it.

[psychocoderHPC]

@franzpoeschel Are checkpoints with your fix always written as one file per checkpoint? This is a strong requirement for picongpu. Standard IO can be optionally in one file with a time series.

[franzpoeschel]

@psychocoderHPC yes, they are. With this fix, I don't even keep the Series open for checkpointing.
EDIT: Wait before merging, I'll actually have to check if I kept the filename the same for checkpoints

[franzpoeschel]

See here @psychocoderHPC
This is the Series for checkpointing, just quickly opened here and then closed again

[franzpoeschel]

It's good that you asked René. The parameter --radiation.openPMDSuffix is read by both the checkpointing and regular output routines, while it should only be read by regular output. Will have to fix.

[franzpoeschel]

Alright, these are now the new parameters:

  --e_radiation.openPMDSuffix arg (=_%T_0_0_0.h5)
                                        Suffix for openPMD filename extension 
                                        and iteration expansion pattern.
  --e_radiation.openPMDCheckpointExtension arg (=h5)
                                        Filename extension for openPMD 
                                        checkpoints.
  --e_radiation.openPMDConfig arg (={}) JSON/TOML configuration for 
                                        initializing openPMD.
  --e_radiation.openPMDCheckpointConfig arg (={})
                                        JSON/TOML configuration for 
                                        initializing openPMD checkpointing.

No --restartConfig parameter for now, since noone will use it anyway.

[PrometheusPi]

Tested in - all files are created