From ea27f61992c85b1ae26d03f4593137075d458656 Mon Sep 17 00:00:00 2001
From: Oliver Hennigh <oliverhennigh@Olivers-MacBook-Air.local>
Date: Thu, 21 May 2026 16:01:25 -0700
Subject: [PATCH] Fix Warp mesh Poisson residual conflicts

---
 .../_warp_impl/_kernels.py                    | 35 +++++++++++++++++++
 .../mesh_poisson_disk_sample/_warp_impl/op.py | 32 ++++++++++++++++-
 2 files changed, 66 insertions(+), 1 deletion(-)

diff --git a/physicsnemo/nn/functional/geometry/mesh_poisson_disk_sample/_warp_impl/_kernels.py b/physicsnemo/nn/functional/geometry/mesh_poisson_disk_sample/_warp_impl/_kernels.py
index 3aec265e39..970219a57f 100644
--- a/physicsnemo/nn/functional/geometry/mesh_poisson_disk_sample/_warp_impl/_kernels.py
+++ b/physicsnemo/nn/functional/geometry/mesh_poisson_disk_sample/_warp_impl/_kernels.py
@@ -208,6 +208,41 @@ def _commit_accepted_candidates(
     accepted_radii[accepted_idx] = candidate_radii[candidate_idx]
 
 
+# Deterministically prune any conflicts left by the parallel candidate pass.
+@wp.kernel
+def _mark_accepted_conflicts(
+    hashgrid_id: wp.uint64,
+    accepted_positions: wp.array(dtype=wp.vec3f),
+    accepted_radii: wp.array(dtype=wp.float32),
+    accepted_alive: wp.array(dtype=wp.int32),
+    search_radius: wp.float32,
+):
+    sample_idx = wp.tid()
+    if accepted_alive[sample_idx] == 0:
+        return
+
+    sample_position = accepted_positions[sample_idx]
+    sample_radius = accepted_radii[sample_idx]
+
+    neighbor_idx = int(0)
+    query = wp.hash_grid_query(hashgrid_id, sample_position, search_radius)
+    while wp.hash_grid_query_next(query, neighbor_idx):
+        if neighbor_idx >= sample_idx:
+            continue
+        if neighbor_idx >= accepted_positions.shape[0]:
+            continue
+
+        neighbor_radius = accepted_radii[neighbor_idx]
+        min_radius = wp.min(sample_radius, neighbor_radius)
+        if _points_too_close(
+            sample_position,
+            accepted_positions[neighbor_idx],
+            min_radius,
+        ):
+            accepted_alive[sample_idx] = 0
+            return
+
+
 # Compute Yuksel sample-elimination contribution for one pairwise distance.
 @wp.func
 def _wse_pair_weight(
diff --git a/physicsnemo/nn/functional/geometry/mesh_poisson_disk_sample/_warp_impl/op.py b/physicsnemo/nn/functional/geometry/mesh_poisson_disk_sample/_warp_impl/op.py
index ae0b280ab3..5e47ef0f0b 100644
--- a/physicsnemo/nn/functional/geometry/mesh_poisson_disk_sample/_warp_impl/op.py
+++ b/physicsnemo/nn/functional/geometry/mesh_poisson_disk_sample/_warp_impl/op.py
@@ -31,6 +31,7 @@
     _count_wse_neighbors,
     _generate_surface_candidates,
     _initialize_wse_weights_from_csr,
+    _mark_accepted_conflicts,
     _mark_wse_deleted_batch,
     _reject_candidates_vs_accepted,
     _resolve_candidate_conflicts,
@@ -851,7 +852,36 @@ def _run_dart_throwing_pass(
             pass_seed=random_seed,
             pass_limit=max_points,
         )
-        return accepted_positions[:final_count].contiguous()
+        if final_count <= 1:
+            return accepted_positions[:final_count].contiguous()
+
+        final_positions = accepted_positions[:final_count]
+        final_radii = accepted_radii[:final_count]
+        final_alive = torch.ones(
+            (final_count,),
+            device=mesh_vertices.device,
+            dtype=torch.int32,
+        )
+        final_search_radius = max(min_distance, adaptive_max_radius)
+        accepted_grid.build(
+            points=wp.from_torch(final_positions, dtype=wp.vec3f),
+            radius=final_search_radius,
+        )
+        wp.launch(
+            kernel=_mark_accepted_conflicts,
+            dim=final_count,
+            inputs=[
+                accepted_grid.id,
+                wp.from_torch(final_positions, dtype=wp.vec3f, return_ctype=True),
+                wp.from_torch(final_radii, dtype=wp.float32, return_ctype=True),
+                wp.from_torch(final_alive, dtype=wp.int32, return_ctype=True),
+                float(final_search_radius),
+            ],
+            device=wp_launch_device,
+            stream=wp_launch_stream,
+        )
+        kept_indices = torch.nonzero(final_alive != 0, as_tuple=False).squeeze(1)
+        return final_positions.index_select(0, kept_indices).contiguous()
 
 
 # Public alias used by the FunctionSpec wrapper.