Developer workflow

Comparing two snapshots

tools/compare_snapshots.py compares two NetCDF snapshots written by aragog run, variable by variable:

python tools/compare_snapshots.py A.nc B.nc --ignore NAME[,NAME...]

The comparison is exact by value: NaN equals NaN, -0.0 equals 0.0, and data types and attributes are not compared. For each variable that differs the tool prints the largest relative difference against A.nc over the positions where both values are finite, and the number of other differing positions (NaN or infinity against another value); string variables are reported as differing values. It also lists each variable present in one file only. Variables named in --ignore (comma-separated, repeatable) are marked (ignored).

The exit code is 0 when nothing outside --ignore differs, 1 when something does, and 2 when a file cannot be read. To check that a change leaves the solver trajectory unchanged, run the same configuration from both checkouts with a short end time, and pass the variables the change is meant to alter to --ignore. A change to the per-call energy integrals, for example, alters only the energy diagnostics:

python tools/compare_snapshots.py main.nc branch.nc \
    --ignore F_cmb,step_solver_residual_J,step_dE_F_int_J,step_dE_F_cmb_J \
    --ignore step_dE_Q_radio_J,step_dE_Q_tidal_J,step_dE_Q_radio_cons_J,step_dE_Q_tidal_cons_J