Fortran produces efficient out-of-the-box code for dealing with multidimensional arrays. That said, most hand-written fortran doesn't compete with an optimized

Fortran produces efficient out-of-the-box code for dealing with multidimensional arrays. That said, most hand-written fortran doesn't compete with an optimized BLAS or tensor library using CPU-tuned intrinsics. For GPUs, hand-optimized libraries in CUDA rule and those are generally called from C++. Hence why you see deep learning generally in C++ (wrapped in python).