feat: Simplify summaries

Rewrite the module for summary statistics to simplify it.  Instead of
using a single struct containing each statistic, use a tuple of structs.
This enables much more code reuse; structs can be mixed and matched
withing the tuple as needed.

BREAKING CHANGE: All but the default summary statistics break.

examples/growth.ipynb

@@ -697,7 +697,7 @@
     "output_dir = \"$(pwd())/output\"\n",
     "num_saves = 100\n",
     "output_times = t_init:(t_final-t_init)/num_saves:t_final\n",
-    "output_config = OutputConfig(output_dir, output_times, summary_statistics=UltraDark.Output.SummaryStatisticsMeanMaxRms)\n",
+    "output_config = OutputConfig(output_dir, output_times, summary_statistics=(Summary.SimulationTime,Summary.MeanDensity,Summary.MaxDensity,Summary.RmsDensityContrast,Summary.ScaleFactor,Summary.TimeStep))\n",
     "\n",
     "options = Config.SimulationConfig(a=a)"
    ]

src/UltraDark.jl

@@ -12,19 +12,19 @@ export Grids, PencilGrids
 export dV
 export Config, SimulationConfig, constant_scale_factor, TimeStepOptions
 export OutputConfig
-export SummaryStatistics, SummaryStatisticsMeanMaxRms
+export Summary
 
 include("grids.jl")
 include("pencil_grids.jl")
 include("phase_diff.jl")
 include("time_step.jl")
+include("summary.jl")
 include("output.jl")
 include("config.jl")
 
 import .Output: OutputConfig
 import .Output: output_grids, output_xyz
 import .Output: output_summary_row, output_summary_header
-import .Output.Summary: SummaryStatistics, SummaryStatisticsMeanMaxRms
 import .Config: SimulationConfig, constant_scale_factor, TimeStepOptions
 
 """

src/output.jl

@@ -5,9 +5,7 @@ import PencilFFTs, MPI
 import NPZ
 using Statistics
 
-include("summary.jl")
-
-import .Summary: output_summary_header, output_summary_row
+import ..Summary: output_summary_header, output_summary_row
 
 export Summary
 export OutputConfig
@@ -38,13 +36,13 @@ struct OutputConfig
     rho::Bool
 
     "Type of summary statistics to collect"
-    summary_statistics::DataType
+    summary_statistics::Tuple
 end
 
 function OutputConfig(
     directory, output_times;
     box=true, slice=false, psi=true, rho=true,
-    summary_statistics=SummaryStatistics,
+    summary_statistics=(Summary.WallTime, Summary.SimulationTime,)
 )
 
     OutputConfig(directory, output_times, box, slice, psi, rho, summary_statistics)