OpenCL support in VkFFT

-This update adds OpenCL backend in VkFFT (VKFFT_BACKEND 3)
-OpenCL backend has similar performance compared to other backends
-devices key works on all backends now
-Major release

CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.10)
 project(Vulkan_FFT)
 set(CMAKE_CONFIGURATION_TYPES "Release" CACHE STRING "" FORCE)
 set(CMAKE_BUILD_TYPE "Release" CACHE STRING "" FORCE)
-set(VKFFT_BACKEND 0)#0 - Vulkan, 1 - CUDA, 2 - HIP
+set(VKFFT_BACKEND 0)#0 - Vulkan, 1 - CUDA, 2 - HIP, 3 - OpenCL
 
 if(${VKFFT_BACKEND} EQUAL 1)
 	option(build_VkFFT_cuFFT_benchmark "Build VkFFT cuFFT benchmark" ON)
@@ -59,6 +59,8 @@ elseif(${VKFFT_BACKEND} EQUAL 2)
 	set_target_properties(hiprt PROPERTIES
 		INTERFACE_LINK_LIBRARIES ${HIP_hiprtc_LIBRARY}
 	)
+elseif(${VKFFT_BACKEND} EQUAL 3)
+	find_package(OpenCL REQUIRED)
 endif()
 target_compile_definitions(${PROJECT_NAME} PUBLIC -DVK_API_VERSION=11)#10 - Vulkan 1.0, 11 - Vulkan 1.1, 12 - Vulkan 1.2 
 if(${VKFFT_BACKEND} EQUAL 0)
@@ -78,6 +80,8 @@ elseif(${VKFFT_BACKEND} EQUAL 1)
 	target_link_libraries(${PROJECT_NAME} PUBLIC cuda ${CUDA_NVRTC_LIB} VkFFT half)
 elseif(${VKFFT_BACKEND} EQUAL 2)
 	target_link_libraries(${PROJECT_NAME} PUBLIC hip::host VkFFT half)
+elseif(${VKFFT_BACKEND} EQUAL 3)
+	target_link_libraries(${PROJECT_NAME} PUBLIC OpenCL::OpenCL VkFFT half)
 endif()
 
 if(build_VkFFT_FFTW_precision)

README.md

@@ -1,6 +1,6 @@
 [![Build Status](https://travis-ci.com/DTolm/VkFFT.svg?token=nMgUQeqx7PXMeCFaXqsb&branch=master)](https://travis-ci.com/github/DTolm/VkFFT)
 # VkFFT - Vulkan/CUDA/HIP Fast Fourier Transform library
-VkFFT is an efficient GPU-accelerated multidimensional Fast Fourier Transform library for Vulkan/CUDA/HIP projects. VkFFT aims to provide community with an open-source alternative to Nvidia's cuFFT library, while achieving better performance. VkFFT is written in C language and supports Vulkan, CUDA and HIP as backends.
+VkFFT is an efficient GPU-accelerated multidimensional Fast Fourier Transform library for Vulkan/CUDA/HIP/OpenCL projects. VkFFT aims to provide community with an open-source alternative to Nvidia's cuFFT library, while achieving better performance. VkFFT is written in C language and supports Vulkan, CUDA, HIP and OpenCL as backends.
 
 ## Join my panel at Nvidia's GTC 2021 in Higher Education and Research category on April 13th, 2021: https://gtc21.event.nvidia.com/
 
@@ -23,7 +23,7 @@ VkFFT is an efficient GPU-accelerated multidimensional Fast Fourier Transform li
   - Multiple feature/batch convolutions - one input, multiple kernels
   - Multiple input/output/temporary buffer split. Allows to use data split between different memory allocations and mitigate 4GB single allocation limit.
   - Works on Nvidia, AMD and Intel GPUs (tested on Nvidia RTX 3080, GTX 1660 Ti, AMD Radeon VII and Intel UHD 620)
-  - VkFFT supports Vulkan, CUDA and HIP as backend to cover wide range of APIs
+  - VkFFT supports Vulkan, CUDA, HIP and OpenCL as backend to cover wide range of APIs
   - Header-only library with Vulkan interface, which allows to append VkFFT directly to user's command buffer. Shaders are compiled once during the plan creation stage
 ## Future release plan
  - ##### Planned
@@ -41,6 +41,9 @@ CUDA/HIP:
 Include the vkFFT.h file and make sure your system has NVRTC/HIPRTC built. Provide the library with correctly chosen VKFFT_BACKEND definition. Only single/double precision for now.\
 To build CUDA/HIP version of benchmark, replace VKFFT_BACKEND in CMakeLists (line 5) with the correct one and optionally enable FFTW. VKFFT_BACKEND=1 for CUDA, VKFFT_BACKEND=2 for HIP.
 
+OpenCL:
+Include the vkFFT.h file. Provide the library with correctly chosen VKFFT_BACKEND definition. Only single/double precision for now.\
+To build OpenCL version of benchmark, replace VKFFT_BACKEND in CMakeLists (line 5) with the value 3 and optionally enable FFTW.
 ## Command-line interface
 VkFFT has a command-line interface with the following set of commands:\
 -h: print help\