From b4603013c77eb50c7888dc4c255417dab004e0cd Mon Sep 17 00:00:00 2001
From: Florian Pfaff <6773539+FlorianPfaff@users.noreply.github.com>
Date: Wed, 15 Jul 2026 17:31:35 +0200
Subject: [PATCH 1/4] Stabilize SO(3) chordal weight normalization

---
 src/pyrecest/smoothers/so3_chordal_mean_smoother.py | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/pyrecest/smoothers/so3_chordal_mean_smoother.py b/src/pyrecest/smoothers/so3_chordal_mean_smoother.py
index 6f7798640..037bd33ff 100644
--- a/src/pyrecest/smoothers/so3_chordal_mean_smoother.py
+++ b/src/pyrecest/smoothers/so3_chordal_mean_smoother.py
@@ -106,13 +106,18 @@ def _normalize_weight_vector(
             if weights_array[idx] < 0.0:
                 raise ValueError(f"{name} must be nonnegative.")
 
-        weight_sum = backend.sum(weights_array)
-        if weight_sum <= 0.0:
+        weight_scale = backend.max(weights_array)
+        if not bool(weight_scale > 0.0):
+            raise ValueError(f"{name} must contain at least one positive entry.")
+
+        scaled_weights = weights_array / weight_scale
+        scaled_weight_sum = backend.sum(scaled_weights)
+        if not bool(isfinite(scaled_weight_sum)) or not bool(scaled_weight_sum > 0.0):
             raise ValueError(f"{name} must contain at least one positive entry.")
 
         if normalize:
-            return weights_array / weight_sum
-        return weights_array
+            return scaled_weights / scaled_weight_sum
+        return scaled_weights
 
     @staticmethod
     def project_to_so3(matrix):

From 7e99d97f2fd32083305f7f3ea8808dc54ba20828 Mon Sep 17 00:00:00 2001
From: Florian Pfaff <6773539+FlorianPfaff@users.noreply.github.com>
Date: Wed, 15 Jul 2026 17:32:24 +0200
Subject: [PATCH 2/4] Add SO(3) extreme-weight regression

---
 .../test_so3_chordal_mean_extreme_weights.py  | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 tests/smoothers/test_so3_chordal_mean_extreme_weights.py

diff --git a/tests/smoothers/test_so3_chordal_mean_extreme_weights.py b/tests/smoothers/test_so3_chordal_mean_extreme_weights.py
new file mode 100644
index 000000000..8ecf0bee9
--- /dev/null
+++ b/tests/smoothers/test_so3_chordal_mean_extreme_weights.py
@@ -0,0 +1,42 @@
+import numpy as np
+import numpy.testing as npt
+
+# pylint: disable=no-name-in-module,no-member
+from pyrecest.backend import array, cos, eye, sin, stack, to_numpy
+from pyrecest.smoothers import SO3ChordalMeanSmoother
+
+
+def _z_rotation(angle):
+    return array(
+        [
+            [cos(angle), -sin(angle), 0.0],
+            [sin(angle), cos(angle), 0.0],
+            [0.0, 0.0, 1.0],
+        ]
+    )
+
+
+def test_chordal_mean_normalizes_extreme_finite_weights_stably():
+    backend_dtype = to_numpy(array([1.0])).dtype
+    maximum = np.finfo(backend_dtype).max
+    rotations = stack([eye(3), _z_rotation(0.5 * np.pi)], axis=0)
+
+    reference = SO3ChordalMeanSmoother.chordal_mean(
+        rotations,
+        weights=array([3.0, 1.0]),
+    )
+    extreme_weights = array(
+        np.asarray([maximum, maximum / 3.0], dtype=backend_dtype)
+    )
+
+    result = SO3ChordalMeanSmoother.chordal_mean(
+        rotations,
+        weights=extreme_weights,
+    )
+
+    npt.assert_allclose(
+        to_numpy(result),
+        to_numpy(reference),
+        rtol=1.0e-5,
+        atol=1.0e-6,
+    )

From a0eac438a865eeb82655ac5de4aafb0bbb32e088 Mon Sep 17 00:00:00 2001
From: Florian Pfaff <6773539+FlorianPfaff@users.noreply.github.com>
Date: Wed, 15 Jul 2026 20:19:30 +0200
Subject: [PATCH 3/4] Trigger CI against repaired main

---
 .github/ci-refresh/4448.txt | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 .github/ci-refresh/4448.txt

diff --git a/.github/ci-refresh/4448.txt b/.github/ci-refresh/4448.txt
new file mode 100644
index 000000000..41e74407b
--- /dev/null
+++ b/.github/ci-refresh/4448.txt
@@ -0,0 +1 @@
+Temporary CI refresh marker.

From 9b3917f11e4df32838b66d5cee65a25996b07e30 Mon Sep 17 00:00:00 2001
From: Florian Pfaff <6773539+FlorianPfaff@users.noreply.github.com>
Date: Wed, 15 Jul 2026 20:19:38 +0200
Subject: [PATCH 4/4] Remove temporary CI refresh marker

---
 .github/ci-refresh/4448.txt | 1 -
 1 file changed, 1 deletion(-)
 delete mode 100644 .github/ci-refresh/4448.txt

diff --git a/.github/ci-refresh/4448.txt b/.github/ci-refresh/4448.txt
deleted file mode 100644
index 41e74407b..000000000
--- a/.github/ci-refresh/4448.txt
+++ /dev/null
@@ -1 +0,0 @@
-Temporary CI refresh marker.