Skip to content

faq.en

Jump to bottom
wiki-sync-bot edited this page Dec 4, 2024 · 1 revision

How to join the technical Community Groups with QQ ？

  • Open QQ -> click the group chat search-> search group number 637093648, enter the answer to the question: conv conv conv conv conv → join the group chat → ready to accept the Turing test(a joke)
  • Open QQ -> search Pocky group: 677104663 (lots experts), the answer to the question

How to watch the author's on live in Bilibili？

Compilation

  • How to download the full source code？

    git clone --recursive https://github.com/Tencent/ncnn/

    or

    download ncnn-xxxxx-full-source.zip

  • How to cross-compile？How to set the cmake toolchain？

    See https://github.com/Tencent/ncnn/wiki/how-to-build

  • The submodules were not downloaded! Please update submodules with "git submodule update --init" and try again

    As above, download the full source code. Or follow the prompts to execute: git submodule update --init

  • Could NOT find Protobuf (missing: Protobuf_INCLUDE_DIR)

    sudo apt-get install libprotobuf-dev protobuf-compiler

  • Could NOT find CUDA (missing: CUDA_TOOLKIT_ROOT_DIR CUDA_INCLUDE_DIRS CUDA_CUDART_LIBRARY)

    https://github.com/Tencent/ncnn/issues/1873

  • Could not find a package configuration file provided by "OpenCV" with any of the following names: OpenCVConfig.cmake opencv-config.cmake

    sudo apt-get install libopencv-dev

    or customized compile and install ，with set(OpenCV_DIR {the dir OpenCVConfig.cmake exist})

  • Could not find a package configuration file provided by "ncnn" with any of the following names: ncnnConfig.cmake ncnn-config.cmake

    set(ncnn_DIR { the dir ncnnConfig.cmake exist})

  • Vulkan not found,

    • cmake requires version >= 3.10, otherwise there is no FindVulkan.cmake

    • android-api >= 24

    • macos has to run the install script first

  • How to install vulkan sdk

  • xxx.lib not found（be specified by system/compiler）

    undefined reference to __kmpc_for_static_init_4 __kmpc_for_static_fini __kmpc_fork_call ...

    Need to link openmp

    undefined reference to vkEnumerateInstanceExtensionProperties vkGetInstanceProcAddr vkQueueSubmit ...

    need vulkan-1.lib

    undefined reference to glslang::InitializeProcess() glslang::TShader::TShader(EShLanguage) ...

    need glslang.lib OGLCompiler.lib SPIRV.lib OSDependent.lib

    undefined reference to AAssetManager_fromJava AAssetManager_open AAsset_seek ...

    Add android to find_library and target_like_libraries

    find_package(ncnn)

  • undefined reference to typeinfo for ncnn::Layer

    opencv rtti -> opencv-mobile

  • undefined reference to __cpu_model

    upgrade compiler / libgcc_s libgcc

  • unrecognized command line option "-mavx2"

    upgrade gcc

  • Why is the compiled ncnn-android library so large？

    See https://github.com/Tencent/ncnn/wiki/build-for-android.zh and see How to trim smaller ncnn

  • ncnnoptimize and custom layer

    ncnnoptimize first before adding a custom layer to avoid ncnnoptimize not being able to handle custom layer saves.

  • rtti/exceptions Conflict

    The reason for the conflict is that the libraries used in the project are configured differently, so analyze whether you need to turn them on or off according to your actual situation. ncnn is ON by default, add the following two parameters when recompiling ncnn.

    • ON: -DNCNN_DISABLE_RTTI=OFF -DNCNN_DISABLE_EXCEPTION=OFF
    • OFF: -DNCNN_DISABLE_RTTI=ON -DNCNN_DISABLE_EXCEPTION=ON

  • error: undefined symbol: ncnn::Extractor::extract(char const*, ncnn::Mat&)

    Possible scenarios.

    • Try upgrading the NDK version of Android Studio

How do I add the ncnn library to my project and how does the cmake method work?

Compile ncnn,and make install. linux/windows should set/export ncnn_DIR points to the directory containing ncnnConfig.cmake under the install directory

  • android

  • ios

  • linux

  • windows

  • macos

  • arm linux

Convert model issues

Mode 1:

ONNX_ATEN_FALLBACK Fully customizable op, first change to one that can export (e.g. concat slice), go to ncnn and then modify param

Way 2.

You can try this with PNNX, see the following article for a general description:

  1. Windows/Linux/macOS steps for compiling PNNX

  2. Learn in 5 minutes! Converting TorchScript models to ncnn models with PNNX

Using

  • vkEnumeratePhysicalDevices failed -3

  • vkCreateInstance failed -9

    Please upgrade your GPU driver if you meet this crash or error. Here are the download sites for some brands of GPU drivers. We have provided some driver download pages here. Intel, AMD, Nvidia www.nvidia.com/Download/index.aspx)

  • ModuleNotFoundError: No module named 'ncnn.ncnn'

    python setup.py develop

  • fopen nanodet-m.param failed

    path should be working dir

    File not found or not readable. Make sure that XYZ.param/XYZ.bin is accessible.

  • find_blob_index_by_name data / output / ... failed

    layer name vs blob name

    param.bin use xxx.id.h enum

  • parse magic failed

  • param is too old, please regenerate

    The model maybe has problems

    Your model file is being the old format converted by an old caffe2ncnn tool.

    Checkout the latest ncnn code, build it and regenerate param and model binary files, and that should work.

    Make sure that your param file starts with the magic number 7767517.

    you may find more info on use-ncnn-with-alexnet

    When adding the softmax layer yourself, you need to add 1=1

  • set_vulkan_compute failed, network use_vulkan_compute disabled

    Set net.opt.use_vulkan_compute = true before load_param / load_model;

  • How to execute multiple blob inputs, multiple blob outputs？

    Multiple execute ex.input() and ex.extract() like following

    ex.input("data1", in_1);
ex.input("data2", in_2);
ex.extract("output1", out_1);
ex.extract("output2", out_2);

  • Multiple executions of Extractor extract double the calculation？

    No

  • How to see the elapsed time for every layer？

    cmake -DNCNN_BENCHMARK=ON ..

  • How to convert a cv::Mat CV_8UC3 BGR image

    from_pixels to_pixels

  • How to convert float data to ncnn::Mat

    First of all, you need to manage the memory you request yourself, at this point ncnn::Mat will not automatically free up the float data you pass over to it

    std::vector<float> testData(60, 1.0); // use std::vector<float> to manage memory requests and releases yourself
ncnn::Mat in1 = ncnn::Mat(60, (void*)testData.data()).reshape(4, 5, 3); // just pass the pointer to the float data as a void*, and even specify the dimension (up says it's best to use reshape to solve the channel gap)
float* a = new float[60]; // New a piece of memory yourself, you need to release it later
ncnn::Mat in2 = ncnn::Mat(60, (void*)a).reshape(4, 5, 3).clone(); // use the same method as above, clone() to transfer data owner
Clone this wiki locally