Comment by stabbles

Probably uses LLVM Flang to make the Fortran parts happen, compiling reference BLAS and LAPACK. As the main dev for WebR is also the one who did this [0].

[0] https://gws.phd/posts/fortran_wasm/

I wonder what kind of edge cases you deal with when blas is your bottleneck in R. Stan code aside, I’ve seen few problems that are neither instant (i.e. sub hours) nor impossible (I.e years of compute).