From f3a78dc505742e1b238afe45afed26e57ce4518c Mon Sep 17 00:00:00 2001
From: inter <inter@qq.com>
Date: Sun, 21 Sep 2025 20:19:14 +0800
Subject: [PATCH] Add File

---
 .../pointnet2_stack/src/interpolate.cpp       | 107 ++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 pcdet/ops/pointnet2/pointnet2_stack/src/interpolate.cpp

diff --git a/pcdet/ops/pointnet2/pointnet2_stack/src/interpolate.cpp b/pcdet/ops/pointnet2/pointnet2_stack/src/interpolate.cpp
new file mode 100644
index 0000000..db9a41a
--- /dev/null
+++ b/pcdet/ops/pointnet2/pointnet2_stack/src/interpolate.cpp
@@ -0,0 +1,107 @@
+/*
+Stacked-batch-data version of point interpolation, modified from the original implementation of official PointNet++ codes.
+Written by Shaoshuai Shi
+All Rights Reserved 2019-2020.
+*/
+
+
+#include <torch/serialize/tensor.h>
+#include <vector>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <cuda.h>
+#include <cuda_runtime_api.h>
+#include "interpolate_gpu.h"
+
+#define CHECK_CUDA(x) do { \
+  if (!x.type().is_cuda()) { \
+    fprintf(stderr, "%s must be CUDA tensor at %s:%d\n", #x, __FILE__, __LINE__); \
+    exit(-1); \
+  } \
+} while (0)
+#define CHECK_CONTIGUOUS(x) do { \
+  if (!x.is_contiguous()) { \
+    fprintf(stderr, "%s must be contiguous tensor at %s:%d\n", #x, __FILE__, __LINE__); \
+    exit(-1); \
+  } \
+} while (0)
+#define CHECK_INPUT(x) CHECK_CUDA(x);CHECK_CONTIGUOUS(x)
+
+
+void three_nn_wrapper_stack(at::Tensor unknown_tensor, 
+    at::Tensor unknown_batch_cnt_tensor, at::Tensor known_tensor, 
+    at::Tensor known_batch_cnt_tensor, at::Tensor dist2_tensor, at::Tensor idx_tensor){
+    // unknown: (N1 + N2 ..., 3)
+    // unknown_batch_cnt: (batch_size), [N1, N2, ...]
+    // known: (M1 + M2 ..., 3)
+    // known_batch_cnt: (batch_size), [M1, M2, ...]
+    // Return:
+    // dist: (N1 + N2 ..., 3)  l2 distance to the three nearest neighbors
+    // idx: (N1 + N2 ..., 3)  index of the three nearest neighbors
+    CHECK_INPUT(unknown_tensor);
+    CHECK_INPUT(unknown_batch_cnt_tensor);
+    CHECK_INPUT(known_tensor);
+    CHECK_INPUT(known_batch_cnt_tensor);
+    CHECK_INPUT(dist2_tensor);
+    CHECK_INPUT(idx_tensor);
+
+    int batch_size = unknown_batch_cnt_tensor.size(0);
+    int N = unknown_tensor.size(0);
+    int M = known_tensor.size(0);
+    const float *unknown = unknown_tensor.data<float>();
+    const int *unknown_batch_cnt = unknown_batch_cnt_tensor.data<int>();
+    const float *known = known_tensor.data<float>();
+    const int *known_batch_cnt = known_batch_cnt_tensor.data<int>();
+    float *dist2 = dist2_tensor.data<float>();
+    int *idx = idx_tensor.data<int>();
+
+    three_nn_kernel_launcher_stack(batch_size, N, M, unknown, unknown_batch_cnt, known, known_batch_cnt, dist2, idx);
+}
+
+
+void three_interpolate_wrapper_stack(at::Tensor features_tensor, 
+    at::Tensor idx_tensor, at::Tensor weight_tensor, at::Tensor out_tensor) {
+    // features_tensor: (M1 + M2 ..., C)
+    // idx_tensor: [N1 + N2 ..., 3]
+    // weight_tensor: [N1 + N2 ..., 3]
+    // Return:
+    // out_tensor: (N1 + N2 ..., C)
+    CHECK_INPUT(features_tensor);
+    CHECK_INPUT(idx_tensor);
+    CHECK_INPUT(weight_tensor);
+    CHECK_INPUT(out_tensor);
+
+    int N = out_tensor.size(0);
+    int channels = features_tensor.size(1);
+    const float *features = features_tensor.data<float>();
+    const float *weight = weight_tensor.data<float>();
+    const int *idx = idx_tensor.data<int>();
+    float *out = out_tensor.data<float>();
+
+    three_interpolate_kernel_launcher_stack(N, channels, features, idx, weight, out);
+}
+
+
+void three_interpolate_grad_wrapper_stack(at::Tensor grad_out_tensor, at::Tensor idx_tensor,
+    at::Tensor weight_tensor, at::Tensor grad_features_tensor) {
+    // grad_out_tensor: (N1 + N2 ..., C)
+    // idx_tensor: [N1 + N2 ..., 3]
+    // weight_tensor: [N1 + N2 ..., 3]
+    // Return:
+    // grad_features_tensor: (M1 + M2 ..., C)
+    CHECK_INPUT(grad_out_tensor);
+    CHECK_INPUT(idx_tensor);
+    CHECK_INPUT(weight_tensor);
+    CHECK_INPUT(grad_features_tensor);
+
+    int N = grad_out_tensor.size(0);
+    int channels = grad_out_tensor.size(1);
+    const float *grad_out = grad_out_tensor.data<float>();
+    const float *weight = weight_tensor.data<float>();
+    const int *idx = idx_tensor.data<int>();
+    float *grad_features = grad_features_tensor.data<float>();
+    
+    // printf("N=%d, channels=%d\n", N, channels);
+    three_interpolate_grad_kernel_launcher_stack(N, channels, grad_out, idx, weight, grad_features);
+}
\ No newline at end of file