diff --git a/pcdet/ops/iou3d_nms/src/iou3d_nms.cpp b/pcdet/ops/iou3d_nms/src/iou3d_nms.cpp
index d41da8ad0..62d3c9db3 100644
--- a/pcdet/ops/iou3d_nms/src/iou3d_nms.cpp
+++ b/pcdet/ops/iou3d_nms/src/iou3d_nms.cpp
@@ -95,7 +95,7 @@ int nms_gpu(at::Tensor boxes, at::Tensor keep, float nms_overlap_thresh){
 
     int boxes_num = boxes.size(0);
     const float * boxes_data = boxes.data<float>();
-    long * keep_data = keep.data<long>();
+    int32_t * keep_data = keep.data<int32_t>();
 
     const int col_blocks = DIVUP(boxes_num, THREADS_PER_BLOCK_NMS);
 
@@ -107,14 +107,14 @@ int nms_gpu(at::Tensor boxes, at::Tensor keep, float nms_overlap_thresh){
     // unsigned long long *mask_cpu = new unsigned long long [boxes_num * col_blocks];
     std::vector<unsigned long long> mask_cpu(boxes_num * col_blocks);
 
-//    printf("boxes_num=%d, col_blocks=%d\n", boxes_num, col_blocks);
+    // printf("boxes_num=%d, col_blocks=%d\n", boxes_num, col_blocks);
     CHECK_ERROR(cudaMemcpy(&mask_cpu[0], mask_data, boxes_num * col_blocks * sizeof(unsigned long long),
                            cudaMemcpyDeviceToHost));
 
     cudaFree(mask_data);
 
-    unsigned long long remv_cpu[col_blocks];
-    memset(remv_cpu, 0, col_blocks * sizeof(unsigned long long));
+    std::vector<unsigned long long> remv_cpu(col_blocks);
+    memset(&remv_cpu[0], 0, col_blocks * sizeof(unsigned long long));
 
     int num_to_keep = 0;
 
@@ -145,7 +145,7 @@ int nms_normal_gpu(at::Tensor boxes, at::Tensor keep, float nms_overlap_thresh){
 
     int boxes_num = boxes.size(0);
     const float * boxes_data = boxes.data<float>();
-    long * keep_data = keep.data<long>();
+    int32_t * keep_data = keep.data<int32_t>();
 
     const int col_blocks = DIVUP(boxes_num, THREADS_PER_BLOCK_NMS);
 
@@ -157,14 +157,14 @@ int nms_normal_gpu(at::Tensor boxes, at::Tensor keep, float nms_overlap_thresh){
     // unsigned long long *mask_cpu = new unsigned long long [boxes_num * col_blocks];
     std::vector<unsigned long long> mask_cpu(boxes_num * col_blocks);
 
-//    printf("boxes_num=%d, col_blocks=%d\n", boxes_num, col_blocks);
+    // printf("boxes_num=%d, col_blocks=%d\n", boxes_num, col_blocks);
     CHECK_ERROR(cudaMemcpy(&mask_cpu[0], mask_data, boxes_num * col_blocks * sizeof(unsigned long long),
                            cudaMemcpyDeviceToHost));
 
     cudaFree(mask_data);
 
-    unsigned long long remv_cpu[col_blocks];
-    memset(remv_cpu, 0, col_blocks * sizeof(unsigned long long));
+    std::vector<unsigned long long> remv_cpu(col_blocks);
+    memset(&remv_cpu[0], 0, col_blocks * sizeof(unsigned long long));
 
     int num_to_keep = 0;
 
diff --git a/pcdet/ops/iou3d_nms/src/iou3d_nms_kernel.cu b/pcdet/ops/iou3d_nms/src/iou3d_nms_kernel.cu
index e5e305cdb..c17d052f2 100644
--- a/pcdet/ops/iou3d_nms/src/iou3d_nms_kernel.cu
+++ b/pcdet/ops/iou3d_nms/src/iou3d_nms_kernel.cu
@@ -11,7 +11,7 @@ All Rights Reserved 2019-2020.
 
 // #define DEBUG
 const int THREADS_PER_BLOCK_NMS = sizeof(unsigned long long) * 8;
-const float EPS = 1e-8;
+constexpr float EPS = 1e-8;
 struct Point {
     float x, y;
     __device__ Point() {}
@@ -40,7 +40,7 @@ __device__ inline float cross(const Point &p1, const Point &p2, const Point &p0)
     return (p1.x - p0.x) * (p2.y - p0.y) - (p2.x - p0.x) * (p1.y - p0.y);
 }
 
-__device__ int check_rect_cross(const Point &p1, const Point &p2, const Point &q1, const Point &q2){
+__device__ int check_rect_cross_cuda(const Point &p1, const Point &p2, const Point &q1, const Point &q2){
     int ret = min(p1.x,p2.x) <= max(q1.x,q2.x)  &&
               min(q1.x,q2.x) <= max(p1.x,p2.x) &&
               min(p1.y,p2.y) <= max(q1.y,q2.y) &&
@@ -62,7 +62,7 @@ __device__ inline int check_in_box2d(const float *box, const Point &p){
 
 __device__ inline int intersection(const Point &p1, const Point &p0, const Point &q1, const Point &q0, Point &ans){
     // fast exclusion
-    if (check_rect_cross(p0, p1, q0, q1) == 0) return 0;
+    if (check_rect_cross_cuda(p0, p1, q0, q1) == 0) return 0;
 
     // check cross standing
     float s1 = cross(q0, p1, p0);