embedded3 S2-7b instruments: the quadratic / full-cells-only pressure probe (Mask::pressure_at_quadratic[_from]) and the DFG 2D-1 test's RTX_E3_DFG_DP_PROBE line; the manufactured sphere's pressure-error read by cell class + six signed wall-point reads, RTX_E3_MMS_SCHEME=tvd, the cut_cell_pressure_ladder and sphere_operator_probe tests (defaults untouched; MMS gates green)

Co-Authored-By: Claude Fable 5.1 <[email protected]>

crates/specialized/rtx-cfd/tests/embedded3_dfg_2d1.rs

@@ -171,6 +171,23 @@ fn dfg_2d_1_on_the_device() {
                 .pressure_at(&field.p, cx + 0.5 * D, CY, zc)
                 .unwrap_or(f64::NAN);
             let dp = p_front - p_back;
+            // S2-7b: the stagnation-point reads by the quadratic fit too.
+            if std::env::var_os("RTX_E3_DFG_DP_PROBE").is_some() {
+                let h = field.grid.dx;
+                let mut line = format!("    Δp probes: linear {dp:.5} (front {p_front:.5} back {p_back:.5})");
+                for (r, full) in [(2.5, false), (3.5, false), (4.5, false), (2.5, true), (3.5, true), (4.5, true)] {
+                    let pf = mask.pressure_at_quadratic_from(&field.p, cx - 0.5 * D, CY, zc, r * h, full);
+                    let pb = mask.pressure_at_quadratic_from(&field.p, cx + 0.5 * D, CY, zc, r * h, full);
+                    let tag = if full { "full-only quad" } else { "quad" };
+                    match (pf, pb) {
+                        (Some(pf), Some(pb)) => {
+                            line += &format!("; {tag} r{r:.1}h {:.5} (front {pf:.5} back {pb:.5})", pf - pb);
+                        }
+                        _ => line += &format!("; {tag} r{r:.1}h n/a"),
+                    }
+                }
+                println!("{line}");
+            }
             let (cd, cl, cd_cv, cl_cv) = (coef * fw[0], coef * fw[1], coef * fcv[0], coef * fcv[1]);
             println!(
                 "  t {t:8.4}: c_D {cd:.4} (CV {cd_cv:.4}, reconstructed {cd_s:.4} skipped {})  c_L {cl:.5} (CV {cl_cv:.5}, reconstructed {cl_s:.5})  Δp {dp:.4}  residual {:.1e} CG {}  [{:.0} s]",