Fortran is still a foundation of many important libraries for numeric computing. A fairly large number of implementations of BLAS are written in Fortran (includ

Fortran is still a foundation of many important libraries for numeric computing. A fairly large number of implementations of BLAS are written in Fortran (including the reference implementation), LAPACK is written in Fortran. One of the first domains solved by programming was efficient implementations of common linear algebra computations. Fortran was the original language of choice for many of those projects. When you care about absolutely optimal performance for these computations you're not going to mess with fined tuned code that has been slowly tweaked and improved for over 50 years.