Error with single time step

[rlbyrne]

I am attempting to process a simulation that contains a single time step only, and the job is failing with this error message:

% Variable is undefined: DATA_DIFF_MEAN.
% Execution halted at: PS_KCUBE         1175
   /home/rbyrne/eppsilon/ps_core/ps_kcube.pro
%                      PS_POWER           20
   /home/rbyrne/eppsilon/ps_core/ps_power.pro
%                      PS_MAIN_PLOTS     272
   /home/rbyrne/eppsilon/ps_core/ps_main_plots.pro
%                      PS_WRAPPER        307
   /home/rbyrne/eppsilon/ps_wrappers/ps_wrapper.pro

My call is ps_wrapper, '/safepool/rbyrne/fhd_outputs/fhd_rlb_process_uv_density_sims_Feb2023', 'sim_uv_spacing_10', /png, /plot_kpar_power, /refresh_ps, /uvf_input, pol_inc=["xx"], /no_evenodd

[rlbyrne]

This was run on the fix_edge_cases branch.

[rlbyrne]

Closed by #154