Transition to Metal
If you’re using OpenCL, which was deprecated in macOS 10.14, for GPU-based computational tasks in your Mac app, we recommend that you transition to Metal and Metal Performance Shaders for access to a wider range of capabilities.
OpenCL documentation and specifications
OpenCL, an open standard defined by the Khronos Group, lets you tap into the parallel computing power of GPUs and multicore CPUs to accelerate compute-intensive tasks in your Mac apps.