I was wondering why the author was using braced initialization like

    size_t i{0};

instead of the more common

    size_t i = 0;

Apparently, braced initialization does not allow narrowing conversion, so you'd get a compiler error for e.g. casting double to float

    size_t i{0.0};

and a warning for

    double d = 0.0;
    size_t i{d};

which might silently overflow size_t otherwise, so this is a bit safer.

In C++, you can get the same effect without the unusual syntax by passing -Wfloat-conversion to gcc/clang, but not sure how to do that with CUDA: