CUDA only support

[byronfa]

I was tinkering with VexCL on an NVidia jetson nano, which only supports cuda. It appears if CL isn't available at all, the project files have issues? (Even if I install OpenCL headers, the lack of a library still causes a failure). Any hints?

-- Looking for CL/cl_platform.h
-- Looking for CL/cl_platform.h - not found
CMake Warning at CMakeLists.txt:180 (message):
The JIT interface requires OpenCL headers to be available.You can download
them from https://github.com/KhronosGroup/OpenCL-HeadersSet
OpenCL_INCLUDE_DIR to the location of the headers.For now, disabling the
JIT target.

CMake Error at CMakeLists.txt:244 (add_library):
add_library cannot create ALIAS target "VexCL::Backend" because target
"OpenCL" does not already exist.

[ddemidov]

Can you try to configure the project with cmake .. -DVEXCL_BACKEND=CUDA? The default value is 'OpenCL', set here:

vexcl/CMakeLists.txt

Line 240 in a0fe836

set(VEXCL_BACKEND "OpenCL" CACHE STRING "Select VexCL backend (OpenCL/CUDA/Compute/JIT/All)")

I agree the choice of the default should be more intelligent and check if the backend is available first.

[ddemidov]

588fab6 should help.

[byronfa]

That got me past the install issues.. I was poking around the examples recently and I get the following:
/usr/bin/ld: cannot find -lVexCL::Backend

What exactly is VexCL::Backend trying to pick up?

Thanks!

[ddemidov]

VexCL::Backend is a cmake alias for one of VexCL::OpenCL, VexCL::CUDA, VexCL::Compute, or VexCL::JIT:

vexcl/CMakeLists.txt

Lines 250 to 258 in 4a99b23

	if("${VEXCL_BACKEND}" STREQUAL "OpenCL")
	add_library(VexCL::Backend ALIAS OpenCL)
	elseif("${VEXCL_BACKEND}" STREQUAL "Compute")
	add_library(VexCL::Backend ALIAS Compute)
	elseif("${VEXCL_BACKEND}" STREQUAL "CUDA")
	add_library(VexCL::Backend ALIAS CUDA)
	elseif("${VEXCL_BACKEND}" STREQUAL "JIT")
	add_library(VexCL::Backend ALIAS JIT)
	endif()

Each of these is an interface cmake target that brings all appropriate includes and libraries. The error you get means that the linker actually tries to link against VexCL::Backend, which most probably means that you did something wrong while poking around. Does git diff show any modified CMakeLists.txt files? If not, I would recommend removing the build directory (or create another one), and reconfigure the examples from scratch.