Can not use libtorch in nvdsparserbbox function

[user66125]

I am using a custom nvdsparsebbox_Yolo.cpp with custom nms algorithm in [https://github.com/DanaHan/Yolov5-in-Deepstream-5.0/blob/master/Deepstream%205.0/nvdsinfer_custom_impl_Yolo/nvdsparsebbox_Yolo.cpp], everything runs well, the num_obj_meta is correct. But when I replace the nms with libtorch version like vision::ops::nms to speed up, in most cases the num_obj_meta is 0. Moreover, even if I add some libtorch operations that don’t affect nms results in the code that uses the original nms, the problem remains. However, the libtorch-version nms result is the same as the orginal nms, so I am confused with these behavior.

Part of code is as follows:

Blockquote
num_obj_meta is correct:

static pool NvDsInferParseYoloX(
std::vector const& outputLayersInfo,
NvDsInferNetworkInfo const& networkInfo,
NvDsInferParseDetectionParams const& detectionParams,
std::vector& objectList
)
{
…
std::vector res;
float *prob = (float *)outputLayerInfo[0].buffer;
// auto options = torch::TensorOptions().device(torch::kCUDA); // add some libtorch operation in orignial code also raises the problem
decode(prob, img_w, img_h);
nms(res, prob, CONF_THRESH, NMS_THRESH);
for(auto &r:res)
{
// put res result in objectList
…
}
}

Blockquote
Blockquote
num_obj_meta is 0 or little:

static pool NvDsInferParseYoloX(
std::vector const& outputLayersInfo,
NvDsInferNetworkInfo const& networkInfo,
NvDsInferParseDetectionParams const& detectionParams,
std::vector& objectList
)
{
…
std::vector res;
float *prob = (float *)outputLayerInfo[0].buffer;
decode(prob, img_w, img_h);
auto options = torch::TensorOptions().device(torch::kCUDA); // same problem using kCPU
auto out = torch::from_blob(prob, {sizes of model output});
// extract bboxes from out tensor after CONF_THRESH filter
…
// extract confs from out tensor after CONF_THRESH fliter
…
auto nms_index = vision::ops::nms(bboxes, confs, NMS_THRESH); // libtorch-version nms

    // put output tensor into objectList
    ....

}

Blockquote
Please provide complete information as applicable to your setup.

• Hardware Platform (Jetson / GPU) : GPU TITANXP
• DeepStream Version : 5.1
• JetPack Version (valid for Jetson only)
• TensorRT Version : 8.2.0.6
• NVIDIA GPU Driver Version (valid for GPU only): 460.67
• Issue Type( questions, new requirements, bugs): questions
• How to reproduce the issue ? (This is for bugs. Including which sample app is using, the configuration files content, the command line used and other details for reproducing)
• Requirement details( This is for new requirement. Including the module name-for which plugin or for which sample application, the function description)

[kayccc]

Sorry for the late response, is this still an issue to support? Thanks

[user66125]

Thank you for your attention. Yes, it is still an issue.

[kesong]

Seems there are still miss something in your customized parser.

[user66125]

I have solved the problem. The key point is the classId in NvDsInferParseObjectInfo. In our model, there is only one class. the classId after the original nms is indeed 0 although it is not explictly assigned a value of 0(classid 0). But the classId after libtorch-version nms is random, so when it is assigned to be 0, it works.