Building OpenCV with oneAPI {#tutorial_oneapi_install}

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Quick start {#tutorial_oneapi_install_quick_start}

oneAPI is Intel's open initiative (now also maintained by the UXL Foundation) that combines a specification and a set of toolkits for programming CPUs, GPUs, FPGAs and NPUs with a single code base. The core is the SYCL standard (single-source C++ for parallelism), complemented by high-performance libraries — oneTBB (parallelism), oneMKL (linear algebra), oneDNN (neural networks), oneVPL (video), etc. Thus, when you compile with oneAPI's DPC++ (icpx) compiler, the binary gains optimized execution paths that choose, at runtime, the best vector instructions or the available device, without changing the source code.

Why compile OpenCV with the oneAPI ecosystem when targeting the CPU:

Simple, because by enabling the CMake options -DWITH_SYCL=ON -DWITH_TBB=ON -DWITH_ONEDNN=ON -DWITH_IPP=ON and using the icpx compiler, the OpenCV core starts to directly invoke oneAPI libraries.
oneDNN replaces the generic kernels of the cv::dnn layer with implementations that exploit AVX2, AVX-512, AMX and VNNI, accelerating convolutions, matmul and network post-processing by up to 3-5× on modern CPUs.
oneTBB takes over the thread pool, scheduling filters like cv::resize, cv::GaussianBlur or the G-API pipeline across all cores without busy-wait.
IPP (now distributed via oneAPI Base Toolkit) provides optimized intrinsic routines for elementary operations (SAD, DFT, median blur), which OpenCV calls when it encounters the HAVE_IPP macro.
All this happens transparently: the source code that uses cv::Mat remains the same, but the linked symbols point to vectorized versions, and the internal dispatcher selects the appropriate vector width at runtime.

CPU Processor Requirements

Systems based on Intel® 64 architectures below are supported both as host and target platforms.

Intel® Core™ processor family or higher
Intel® Xeon® processor family
Intel® Xeon® Scalable processor family

Requirements for Accelerators

Integrated GEN9 (and higher) GPUs. See source in Intel® Graphics Compiler for OpenCL™
FPGA Card: see Intel(R) DPC++ Compiler System Requirements.

Disk Space Requirements

3.3 GB of disk space (minimum) on a standard installation.

@note: During the installation process, the installer may need up to 6 GB of additional temporary disk storage to manage the download and intermediate installation files.

Memory Requirements

8 GB RAM recommended

How To install oneAPI

Installing oneAPI: To quickly set up the oneAPI ecosystem on openSUSE, simply follow the official guide https://www.intel.com/content/www/us/en/developer/articles/guide/installation-guide-for-oneapi-toolkits.html, which shows you how to enable the distribution’s dedicated repository (zypper ar … oneAPI) and install the metapackages ― for example, intel-basekit (DPC++, TBB, oneDNN, IPP compilers) and, optionally, intel-hpckit or intel-renderkit if you need HPC or graphics tools. The guide also explains post-installation tweaks, such as loading the environment with source /opt/intel/oneapi/setvars.sh , ensuring that the binaries (icpx, dpcpp) and libraries are immediately available in your shell for compiling and running accelerated applications.

Download, Github Instruction, Build and Install

Below are the commands to download last version (latest release on the date of publication of this text):
```
git clone https://github.com/opencv/opencv.git
```
and make sure you are using branch 4.*:
```
git status
On branch 4.x
```
Navigate to OpenCV repository and prepare the build folder:
```
cd opencv
mkdir build
cd build
```
Set up Intel oneAPI environment variables. For default installation:
```
source /opt/intel/oneapi/setvars.sh
```

Run CMake * with Intel® oneAPI DPC++/C++ Compiler to configure the project:

cmake -DCMAKE_C_COMPILER=icx \
   -DCMAKE_CXX_COMPILER=icpx
   -DCMAKE_CXX_FLAGS="-march=native -mavx -mfma -msse -msse2" ..
cmake --build .

Now Make sure openCV* is compiled with Intel® oneAPI DPC++/C++ Compiler and install:

readelf -p .comment bin/opencv_annotation
String dump of section '.comment':
[     0]  GCC: (SUSE Linux) 13.3.1 20250313 [revision 4ef1d8c84faeebffeb0cc01ee22e891b41e5c4e0]
[    56]  GCC: (SUSE Linux) 12.3.0
[    6f]  Intel(R) oneAPI DPC++/C++ Compiler 2025.1.1 (2025.1.1.20250418)
make install

Have fun...

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