Record gravity relift work before descent rejection

experiments/GRAVITY_DIRECTION_DIAGNOSTICS_2026-09-17.md

@@ -0,0 +1,26 @@
+# Gravity work accounting on direction rejection
+
+The combined polynomial-enthalpy and reduced-gravity strategy checks descent
+twice: once when selecting the enthalpy repair, and again after lifting the
+repaired retained direction into gravity coordinates. A successful gravity
+relift performs real auxiliary work even when the second check rejects the
+direction before line search.
+
+Previously, the successful-relift diagnostics were copied only after the second
+check. Its early rejection could therefore leave solve counts, iteration counts,
+timings, and the last inner residual at their earlier linear-solve snapshot.
+The snapshot now occurs immediately after successful direction capture and
+before the final descent check. Linear-report coordinates retain their existing
+meaning; this changes no tolerance, direction, state, or acceptance decision.
+
+The immutable `b21fa40` rotating `positivity-reduced` artifact records 20 gravity
+solves and a positive final merit slope. Those counters can omit a successful
+last relift: they do not distinguish rejection during enthalpy repair from
+rejection after relifting. Its `direction_repairs` count also includes a chosen
+positive repair fraction whose candidate subsequently fails descent. Historical
+artifacts must retain these qualifications rather than being retroactively
+interpreted as complete work counters.
+
+The regression is a repeat of that bounded combined rotating case, checking
+unchanged accepted states and residual history while accounting for all
+successful relift work. No extra numerical fixture or solver change is needed.

libmeanfield/interface/solver/newton_numerics.cppm

@@ -72,6 +72,8 @@ export namespace mean_field::solver::nonlinear {
 
     struct NumericalStrategyDiagnostics final {
         int polynomialChecks{0};
+        // Nonzero repair proposals include directions later rejected by a
+        // descent check; this measures repair activity, not accepted steps.
         int directionRepairs{0};
         double lastRepairFraction{0.0};
         double lastMeritDirectionalDerivative{0.0};

libmeanfield/interface/solver/stellar_newton_strategy.cppm

@@ -440,6 +440,9 @@ namespace mean_field::solver::detail {
                     return false;
                 }
             }
+            // A successful gravity relift still belongs in the work report if
+            // the following full-merit check rejects the repaired direction.
+            m_gravity.CopyDiagnostics(diagnostics);
             if constexpr (altersDirection && std::same_as<Gravity, nonlinear::EliminatedGravity>) {
                 mfem::Vector action(state.Problem().EquationSize());
                 state.normalizedOperator->Mult(state.normalizedCorrection, action);
@@ -448,7 +451,6 @@ namespace mean_field::solver::detail {
                 if (!std::isfinite(diagnostics.lastMeritDirectionalDerivative) ||
                     diagnostics.lastMeritDirectionalDerivative >= 0.0) { return false; }
             }
-            m_gravity.CopyDiagnostics(diagnostics);
             return true;
         }
         auto PrepareTrial(State &state, const double alpha, nonlinear::NumericalStrategyDiagnostics &diagnostics) {