From b921efae3e52dcd93e553db3d02378951e894769 Mon Sep 17 00:00:00 2001
From: Jeremy Reizenstein <reizenstein@meta.com>
Date: Fri, 5 May 2023 05:59:14 -0700
Subject: [PATCH] CUB usage fix for sample_farthest_points

Summary: Fix for https://github.com/facebookresearch/pytorch3d/issues/1529

Reviewed By: shapovalov

Differential Revision: D45569211

fbshipit-source-id: 8c485f26cd409cafac53d4d982a03cde81a1d853
---
 .../csrc/sample_farthest_points/sample_farthest_points.cu   | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/pytorch3d/csrc/sample_farthest_points/sample_farthest_points.cu b/pytorch3d/csrc/sample_farthest_points/sample_farthest_points.cu
index d9b8df81..70cef75c 100644
--- a/pytorch3d/csrc/sample_farthest_points/sample_farthest_points.cu
+++ b/pytorch3d/csrc/sample_farthest_points/sample_farthest_points.cu
@@ -155,7 +155,7 @@ at::Tensor FarthestPointSamplingCuda(
 
   // Max possible threads per block
   const int MAX_THREADS_PER_BLOCK = 1024;
-  const size_t threads = max(min(1 << points_pow_2, MAX_THREADS_PER_BLOCK), 1);
+  const size_t threads = max(min(1 << points_pow_2, MAX_THREADS_PER_BLOCK), 2);
 
   // Create the accessors
   auto points_a = points.packed_accessor64<float, 3, at::RestrictPtrTraits>();
@@ -215,10 +215,6 @@ at::Tensor FarthestPointSamplingCuda(
       FarthestPointSamplingKernel<2><<<threads, threads, shared_mem, stream>>>(
           points_a, lengths_a, K_a, idxs_a, min_point_dist_a, start_idxs_a);
       break;
-    case 1:
-      FarthestPointSamplingKernel<1><<<threads, threads, shared_mem, stream>>>(
-          points_a, lengths_a, K_a, idxs_a, min_point_dist_a, start_idxs_a);
-      break;
     default:
       FarthestPointSamplingKernel<1024>
           <<<blocks, threads, shared_mem, stream>>>(