prescribed-motion replay: per-step Schwarz rounds, convergence, background residual, patch divergence and mass defects in the CSV — so the next burst is seen forming

Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam

crates/specialized/rtx-fsi/tests/turek_hron_fsi2_overset.rs

@@ -411,7 +411,7 @@ fn fsi2_overset_prescribed_motion() {
         let mut f = std::fs::File::create(p).expect("csv");
         writeln!(
             f,
-            "t,uy_tip,drag,lift,power,wall_flux,area_rate,p_faces,p_normal,p_tangential,p_root,p_mid,p_tip"
+            "t,uy_tip,drag,lift,power,wall_flux,area_rate,p_faces,p_normal,p_tangential,p_root,p_mid,p_tip,rounds_max,schwarz_ok,bg_residual,patch_div,defect_patch,defect_bg"
         )
         .unwrap();
         f
@@ -436,9 +436,16 @@ fn fsi2_overset_prescribed_motion() {
         if let Err(e) = fluid.set_geometry(&d_r, &v_r) {
             panic!("set_geometry died at step {step}, t = {t_new:.4}: {e:?}");
         }
-        if let Err(e) = fluid.step() {
-            panic!("fluid step died at step {step}, t = {t_new:.4}: {e:?}");
-        }
+        let (rounds_max, schwarz_ok, bg_res, patch_div) = match fluid.step() {
+            Ok(r) => (
+                r.rounds.iter().copied().max().unwrap_or(0),
+                r.schwarz_converged,
+                r.background_residual,
+                r.patch_max_divergence,
+            ),
+            Err(e) => panic!("fluid step died at step {step}, t = {t_new:.4}: {e:?}"),
+        };
+        let (defect_patch, defect_bg, _) = fluid.last_defects.get();
         fluid.commit_base();
         let (nodal, _, _) = fluid.sample_load(&d_r);
         let power: f64 = nodal
@@ -515,8 +522,8 @@ fn fsi2_overset_prescribed_motion() {
             use std::io::Write as _;
             writeln!(
                 f,
-                "{t_new:.6},{uy_tip:.6e},{drag:.4},{lift:.4},{power:.6e},{wall_flux:.6e},{area_rate:.6e},{p_faces:.6e},{p_normal:.6e},{p_tangential:.6e},{:.6e},{:.6e},{:.6e}",
-                p_thirds[0], p_thirds[1], p_thirds[2]
+                "{t_new:.6},{uy_tip:.6e},{drag:.4},{lift:.4},{power:.6e},{wall_flux:.6e},{area_rate:.6e},{p_faces:.6e},{p_normal:.6e},{p_tangential:.6e},{:.6e},{:.6e},{:.6e},{rounds_max},{},{bg_res:.3e},{patch_div:.3e},{defect_patch:.3e},{defect_bg:.3e}",
+                p_thirds[0], p_thirds[1], p_thirds[2], schwarz_ok as u8
             )
             .unwrap();
         }