add ort nms op (#803)

* add ort nms op

* fit lint check

* fix lint check

* update code

* fix lint check

* update code

* update code

* update code

* update code

* update code

* update code

mmcv/ops/csrc/onnxruntime/cpu/nms.cpp

+#include "nms.h"
+
+#include <assert.h>
+
+#include <algorithm>
+#include <cmath>
+#include <iostream>
+#include <iterator>
+#include <vector>
+
+#include "../ort_mmcv_utils.h"
+
+NmsKernel::NmsKernel(OrtApi api, const OrtKernelInfo *info)
+    : api_(api), ort_(api_), info_(info) {
+  iou_threshold_ = ort_.KernelInfoGetAttribute<float>(info, "iou_threshold");
+  offset_ = ort_.KernelInfoGetAttribute<int64_t>(info, "offset");
+
+  // create allocator
+  allocator_ = Ort::AllocatorWithDefaultOptions();
+}
+
+void NmsKernel::Compute(OrtKernelContext *context) {
+  const float iou_threshold = iou_threshold_;
+  const int64_t offset = offset_;
+
+  const OrtValue *boxes = ort_.KernelContext_GetInput(context, 0);
+  const float *boxes_data =
+      reinterpret_cast<const float *>(ort_.GetTensorData<float>(boxes));
+  const OrtValue *scores = ort_.KernelContext_GetInput(context, 1);
+  const float *scores_data =
+      reinterpret_cast<const float *>(ort_.GetTensorData<float>(scores));
+
+  OrtTensorDimensions boxes_dim(ort_, boxes);
+  OrtTensorDimensions scores_dim(ort_, scores);
+
+  int64_t nboxes = boxes_dim[0];
+  assert(boxes_dim[1] == 4);
+
+  // allocate tmp memory
+  float *tmp_boxes = (float *)allocator_.Alloc(sizeof(float) * nboxes * 4);
+  float *sc = (float *)allocator_.Alloc(sizeof(float) * nboxes);
+  float *areas = (float *)allocator_.Alloc(sizeof(float) * nboxes);
+  bool *select = (bool *)allocator_.Alloc(sizeof(bool) * nboxes);
+  for (int64_t i = 0; i < nboxes; i++) {
+    select[i] = true;
+  }
+
+  memcpy(tmp_boxes, boxes_data, sizeof(float) * nboxes * 4);
+  memcpy(sc, scores_data, sizeof(float) * nboxes);
+
+  // sort scores
+  std::vector<float> tmp_sc;
+  for (int i = 0; i < nboxes; i++) {
+    tmp_sc.push_back(sc[i]);
+  }
+  std::vector<int64_t> order(tmp_sc.size());
+  std::iota(order.begin(), order.end(), 0);
+  std::sort(order.begin(), order.end(), [&tmp_sc](int64_t id1, int64_t id2) {
+    return tmp_sc[id1] > tmp_sc[id2];
+  });
+
+  // area = (x2 - x1 + offset) * (y2 - y1 + offset)
+  for (int64_t i = 0; i < nboxes; i++) {
+    areas[i] = (tmp_boxes[i * 4 + 2] - tmp_boxes[i * 4 + 0] + offset) *
+               (tmp_boxes[i * 4 + 3] - tmp_boxes[i * 4 + 1] + offset);
+  }
+
+  for (int64_t _i = 0; _i < nboxes; _i++) {
+    if (select[_i] == false) continue;
+    auto i = order[_i];
+    auto ix1 = tmp_boxes[i * 4 + 0];
+    auto iy1 = tmp_boxes[i * 4 + 1];
+    auto ix2 = tmp_boxes[i * 4 + 2];
+    auto iy2 = tmp_boxes[i * 4 + 3];
+    auto iarea = areas[i];
+
+    for (int64_t _j = _i + 1; _j < nboxes; _j++) {
+      if (select[_j] == false) continue;
+      auto j = order[_j];
+      auto xx1 = std::max(ix1, tmp_boxes[j * 4 + 0]);
+      auto yy1 = std::max(iy1, tmp_boxes[j * 4 + 1]);
+      auto xx2 = std::min(ix2, tmp_boxes[j * 4 + 2]);
+      auto yy2 = std::min(iy2, tmp_boxes[j * 4 + 3]);
+
+      auto w = std::max(0.f, xx2 - xx1 + offset);
+      auto h = std::max(0.f, yy2 - yy1 + offset);
+      auto inter = w * h;
+      auto ovr = inter / (iarea + areas[j] - inter);
+      if (ovr >= iou_threshold) select[_j] = false;
+    }
+  }
+  std::vector<int64_t> res_order;
+  for (int i = 0; i < nboxes; i++) {
+    if (select[i]) {
+      res_order.push_back(order[i]);
+    }
+  }
+
+  std::vector<int64_t> inds_dims({res_order.size()});
+
+  OrtValue *res = ort_.KernelContext_GetOutput(context, 0, inds_dims.data(),
+                                               inds_dims.size());
+  int64_t *res_data = ort_.GetTensorMutableData<int64_t>(res);
+
+  memcpy(res_data, res_order.data(), sizeof(int64_t) * res_order.size());
+}

mmcv/ops/csrc/onnxruntime/cpu/onnxruntime_register.cpp

 #include "onnxruntime_register.h"
 
+#include "nms.h"
 #include "ort_mmcv_utils.h"
 #include "roi_align.h"
 #include "soft_nms.h"
 
 const char *c_MMCVOpDomain = "mmcv";
 SoftNmsOp c_SoftNmsOp;
+NmsOp c_NmsOp;
 MMCVRoiAlignCustomOp c_MMCVRoiAlignCustomOp;
 
 OrtStatus *ORT_API_CALL RegisterCustomOps(OrtSessionOptions *options,
@@ -21,6 +23,10 @@ OrtStatus *ORT_API_CALL RegisterCustomOps(OrtSessionOptions *options,
     return status;
   }
 
+  if (auto status = ortApi->CustomOpDomain_Add(domain, &c_NmsOp)) {
+    return status;
+  }
+
   if (auto status =
           ortApi->CustomOpDomain_Add(domain, &c_MMCVRoiAlignCustomOp)) {
     return status;

mmcv/ops/csrc/onnxruntime/nms.h

+#ifndef ONNXRUNTIME_NMS_H
+#define ONNXRUNTIME_NMS_H
+
+#include <onnxruntime_cxx_api.h>
+
+struct NmsKernel {
+  NmsKernel(OrtApi api, const OrtKernelInfo *info);
+
+  void Compute(OrtKernelContext *context);
+
+ protected:
+  OrtApi api_;
+  Ort::CustomOpApi ort_;
+  const OrtKernelInfo *info_;
+  Ort::AllocatorWithDefaultOptions allocator_;
+
+  float iou_threshold_;
+  int64_t offset_;
+};
+
+struct NmsOp : Ort::CustomOpBase<NmsOp, NmsKernel> {
+  void *CreateKernel(OrtApi api, const OrtKernelInfo *info) const {
+    return new NmsKernel(api, info);
+  };
+
+  const char *GetName() const { return "NonMaxSuppression"; };
+
+  size_t GetInputTypeCount() const { return 2; };
+  ONNXTensorElementDataType GetInputType(size_t /*index*/) const {
+    return ONNX_TENSOR_ELEMENT_DATA_TYPE_FLOAT;
+  };
+
+  size_t GetOutputTypeCount() const { return 1; };
+  ONNXTensorElementDataType GetOutputType(size_t index) const {
+    return ONNX_TENSOR_ELEMENT_DATA_TYPE_INT64;
+  }
+
+  // force cpu
+  const char *GetExecutionProviderType() const {
+    return "CPUExecutionProvider";
+  }
+};
+
+#endif

mmcv/ops/nms.py

@@ -21,11 +21,22 @@ class NMSop(torch.autograd.Function):
 
     @staticmethod
     def symbolic(g, bboxes, scores, iou_threshold, offset):
+        from ..onnx import is_custom_op_loaded
+        has_custom_op = is_custom_op_loaded()
+        if has_custom_op:
+            return g.op(
+                'mmcv::NonMaxSuppression',
+                bboxes,
+                scores,
+                iou_threshold_f=float(iou_threshold),
+                offset_i=int(offset))
+        else:
             from torch.onnx.symbolic_opset9 import select, squeeze, unsqueeze
             boxes = unsqueeze(g, bboxes, 0)
             scores = unsqueeze(g, unsqueeze(g, scores, 0), 0)
             max_output_per_class = g.op(
-            'Constant', value_t=torch.tensor([sys.maxsize], dtype=torch.long))
+                'Constant',
+                value_t=torch.tensor([sys.maxsize], dtype=torch.long))
             iou_threshold = g.op(
                 'Constant',
                 value_t=torch.tensor([iou_threshold], dtype=torch.float))
@@ -35,8 +46,9 @@ class NMSop(torch.autograd.Function):
                 g,
                 select(
                     g, nms_out, 1,
-                g.op('Constant', value_t=torch.tensor([2], dtype=torch.long))),
-            1)
+                    g.op(
+                        'Constant',
+                        value_t=torch.tensor([2], dtype=torch.long))), 1)
 
 
 class SoftNMSop(torch.autograd.Function):
@@ -142,13 +154,7 @@ def nms(boxes, scores, iou_threshold, offset=0):
             select = ext_module.nms(*indata_list, **indata_dict)
         inds = order.masked_select(select)
     else:
-        if torch.onnx.is_in_onnx_export() and offset == 0:
-            # ONNX only support offset == 1
-            boxes[:, -2:] -= 1
         inds = NMSop.apply(boxes, scores, iou_threshold, offset)
-        if torch.onnx.is_in_onnx_export() and offset == 0:
-            # ONNX only support offset == 1
-            boxes[:, -2:] += 1
     dets = torch.cat((boxes[inds], scores[inds].reshape(-1, 1)), dim=1)
     if is_numpy:
         dets = dets.cpu().numpy()

tests/test_ops/test_onnx.py

@@ -24,7 +24,7 @@ class WrapFunction(nn.Module):
 
 
 def test_nms():
-    from mmcv.ops import nms
+    from mmcv.ops import get_onnxruntime_op_path, nms
     np_boxes = np.array([[6.0, 3.0, 8.0, 7.0], [3.0, 6.0, 9.0, 11.0],
                          [3.0, 7.0, 10.0, 12.0], [1.0, 4.0, 13.0, 7.0]],
                         dtype=np.float32)
@@ -46,12 +46,19 @@ def test_nms():
             opset_version=11)
     onnx_model = onnx.load(onnx_file)
 
+    ort_custom_op_path = get_onnxruntime_op_path()
+    if not os.path.exists(ort_custom_op_path):
+        pytest.skip('nms for onnxruntime is not compiled.')
+
+    session_options = rt.SessionOptions()
+    session_options.register_custom_ops_library(ort_custom_op_path)
+
     # get onnx output
     input_all = [node.name for node in onnx_model.graph.input]
     input_initializer = [node.name for node in onnx_model.graph.initializer]
     net_feed_input = list(set(input_all) - set(input_initializer))
     assert (len(net_feed_input) == 2)
-    sess = rt.InferenceSession(onnx_file)
+    sess = rt.InferenceSession(onnx_file, session_options)
     onnx_dets, _ = sess.run(None, {
         'scores': scores.detach().numpy(),
         'boxes': boxes.detach().numpy()