Write a live snapshot of the current solution to snapshot_file.
The file is overwritten on each call. A header comment records the
current iteration and time; subsequent rows are (x, ρ, u, p) via
write_cell_row. Open/write failures are logged as warnings rather
than fatal errors so that a snapshot glitch does not abort the run.
This file path is retained for compatibility with legacy file-watching
tooling; new integrations should prefer the polling session/API surface.
| Type | Intent | Optional | Attributes | Name | ||
|---|---|---|---|---|---|---|
| type(solver_run_context_t), | intent(in) | :: | ctx |
Solver context (read-only). |