cpp14

Describe the bug
When compiler flags are such that __FILE__ macro is replaced with a relative file path (on MSVC no /Z7, /Zi or /ZI and no /FC) then it might be replaced with just a filename with no path separators. In this case tags for tests with --filenames-as-tags do not contain '#' symbol.

The bug is present in the 2.x branch, but not in the main branch where the relevant code has

There is constexpr, consteval but constinit is not described.
It could be worth to add it.

First of all, great library!

I am having some confusion in understanding the role of values_first2 in set_difference_by_key as mentioned here.

In general terms, the result of set difference D = A - B will not contain values from B therefore values_first2 can never be part of D. So `val

There is some inconsistency in the documentation for cub::DeviceSpmv (https://nvlabs.github.io/cub/structcub_1_1_device_spmv.html). The overview says

The SpMV computation performs the matrix-vector operation y = alpha*A*x + beta*y,

But the function signature of CsrMV has neither alpha nor beta, and the function's description says

This function performs the matrix-vector 

This is for first-time-contributors :
Add functions which belong to a particular header file in its corresponding .md file inside the header folder.
For example
std::sort belongs to algorithm header file, so make a new file sort.md inside the algorithm directory while maintaining the CONTIBUTING gu