[Bug/Feature Request] fields::dump fails with dispersive materials (non-null polarization_state)

[jaeukk]

Dear MEEP Team,

I would like to start by thanking the developers for your hard work on this package; the Python interface has been an invaluable tool for my research into dielectric composites over the last few years.

I am currently transitioning to 2D simulations of plasmonic metamaterials. Due to the increased computational load of dispersive media, I am attempting to use the checkpointing (dump/load) feature. However, I encountered the following error during the dump process:

creating epsilon from file "./fields-Ag/reg1_checkpoints/rank02/structure.h5" (0)...
creating epsilon from file "./fields-Ag/reg1_checkpoints/rank00/structure.h5" (0)...
creating epsilon from file "./fields-Ag/reg1_checkpoints/rank03/structure.h5" (0)...
creating epsilon from file "./fields-Ag/reg1_checkpoints/rank01/structure.h5" (0)...
creating fields output file "./fields-Ag/reg1_checkpoints/rank03/fields.h5" (0)...
creating fields output file "./fields-Ag/reg1_checkpoints/rank00/fields.h5" (0)...
meep: non-null polarization_state in fields::dump (unsupported)
Abort(1) on node 3 (rank 3 in comm 0): application called MPI_Abort(MPI_COMM_WORLD, 1) - process 3
meep: non-null polarization_state in fields::dump (unsupported)
Abort(1) on node 0 (rank 0 in comm 0): application called MPI_Abort(MPI_COMM_WORLD, 1) - process 0

Questions:

1. Does MEEP currently lack support for dumping/loading checkpoints when dispersive materials (and their associated polarization states) are present?
2. Are there any known workarounds or plans to support this in a future release?

Thanks!