Is openVX open sourced? I cannot find the definition of vxuGaussianPyramid

This github project has an open source "sample" implementation of OpenVX provided by the Khronos OpenVX working group. It does not claim to be optimized, but may be a good starting point for others to contribute to or use as-is with no guarantees. Different chip vendors may have optimized implementations that they maintain and distribute on their own terms since OpenVX is an Open Standard API interface (see conformant implementations at https://www.khronos.org/openvx/). There are 2 other related github projects that the Khronos group maintains:

OpenVX Specification documentation and headers: https://github.com/KhronosGroup/OpenVX-api-docs
OpenVX Conformant Test Suite: https://github.com/KhronosGroup/OpenVX-cts

Specifically, the declaration of the vxuGaussianPyaramid is in the api-docs project, here: https://github.com/KhronosGroup/OpenVX-api-docs/blob/51851eceaab76bfba30e91617352c8ea49a8ca72/include/VX/vxu.h#L312

And the definition of this vxuGaussianPyramid is in this project, located here:

OpenVX-sample-impl/sample/vxu/vx_utility.c

Line 609 in df31e01

    
           VX_API_ENTRY vx_status VX_API_CALL vxuGaussianPyramid(vx_context context, vx_image input, vx_pyramid gaussian)