From 85594a89f74e7c0bf9079d64488859c7dd132766 Mon Sep 17 00:00:00 2001
From: rois1995 <rauxa1995@hotmail.it>
Date: Thu, 15 Oct 2026 15:48:21 +0200
Subject: [PATCH 1/3] BCGSTAB: do not return the initial guess as the best
 iterate

When no BCGSTAB step lowered the residual, the initial guess (zero) was
returned, so the variables got no update. With few linear iterations
(RAE2822 SA, LINEAR_SOLVER_ITER= 3) the turbulence variable stayed frozen.
Only the computed iterates are now candidates.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 Common/src/linear_algebra/CSysSolve.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/Common/src/linear_algebra/CSysSolve.cpp b/Common/src/linear_algebra/CSysSolve.cpp
index c1a356dfbcc..ae4c7fa72eb 100644
--- a/Common/src/linear_algebra/CSysSolve.cpp
+++ b/Common/src/linear_algebra/CSysSolve.cpp
@@ -1137,7 +1137,6 @@ unsigned long CSysSolve<ScalarType>::BCGSTAB_LinSolver(const CSysVector<ScalarTy
 
   ScalarType alpha = 1.0, omega = 1.0, rho = 1.0, rho_prime = 1.0;
   ScalarType norm_best = norm_r;
-  if (config->GetComm_Level() == COMM_FULL) x_best = x;
   p = ScalarType(0.0);
   v = ScalarType(0.0);
   r_0 = r;
@@ -1198,7 +1197,7 @@ unsigned long CSysSolve<ScalarType>::BCGSTAB_LinSolver(const CSysVector<ScalarTy
       /*--- Check if solution has converged, else output the relative residual if necessary ---*/
 
       norm_r = r.norm();
-      if (norm_r < norm_best) {
+      if ((i == 0) || (norm_r < norm_best)) {
         norm_best = norm_r;
         x_best = x;
       }
@@ -1211,7 +1210,8 @@ unsigned long CSysSolve<ScalarType>::BCGSTAB_LinSolver(const CSysVector<ScalarTy
     }
   }
 
-  /*--- BCGSTAB does not reduce the residual monotonically, return the best iterate. ---*/
+  /*--- BCGSTAB does not reduce the residual monotonically, return the best iterate.
+   * The initial guess is not a candidate, returning it would mean no update at all. ---*/
 
   if ((config->GetComm_Level() == COMM_FULL) && (norm_r > norm_best)) {
     x = x_best;

From e5ced6969679670402b0a3496c4d9eac99ffd271 Mon Sep 17 00:00:00 2001
From: rois1995 <rauxa1995@hotmail.it>
Date: Thu, 15 Oct 2026 16:46:42 +0200
Subject: [PATCH 2/3] Update the reference values of the wedge regression test
 from CI

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 TestCases/hybrid_regression.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/TestCases/hybrid_regression.py b/TestCases/hybrid_regression.py
index 2475709cf54..d80b77abf4c 100644
--- a/TestCases/hybrid_regression.py
+++ b/TestCases/hybrid_regression.py
@@ -80,7 +80,7 @@ def main():
     wedge.cfg_dir   = "euler/wedge"
     wedge.cfg_file  = "inv_wedge_HLLC.cfg"
     wedge.test_iter = 20
-    wedge.test_vals = [ 0.036140, 6.976887, -0.219795, 0.055341]
+    wedge.test_vals = [-0.203988, 5.834709, -0.245436, 0.043358]
     test_list.append(wedge)
 
     # ONERA M6 Wing

From 850358ebb07f8505195483d3c62206cad56db89f Mon Sep 17 00:00:00 2001
From: rois1995 <rauxa1995@hotmail.it>
Date: Wed, 21 Oct 2026 11:39:05 +0200
Subject: [PATCH 3/3] Update the reference values of turbmod_sa_neg_rae2822
 from CI

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013YFdgQwrRqCQ2ihG446aNe
---
 TestCases/parallel_regression.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/TestCases/parallel_regression.py b/TestCases/parallel_regression.py
index 30824edc691..ae6c79c1664 100755
--- a/TestCases/parallel_regression.py
+++ b/TestCases/parallel_regression.py
@@ -957,7 +957,7 @@ def main():
     turbmod_sa_neg_rae2822.cfg_dir   = "turbulence_models/sa/rae2822"
     turbmod_sa_neg_rae2822.cfg_file  = "turb_SA_NEG_RAE2822.cfg"
     turbmod_sa_neg_rae2822.test_iter = 10
-    turbmod_sa_neg_rae2822.test_vals = [1.275994, 1.062588, -2.067822, 1.300662, 0.480881, 0.000000]
+    turbmod_sa_neg_rae2822.test_vals = [1.316535, 1.043996, 4.236921, 1.270979, 0.463385, 0.000000]
     turbmod_sa_neg_rae2822.test_vals_aarch64 = [-1.345593, 1.448310, 1.208721, -0.846597, 1.248410, 0.489117, 0.000000]
     test_list.append(turbmod_sa_neg_rae2822)