We need a language to write differentiable algorithms, and Flux takes Julia to be this language. Being designed from the ground up for mathematical and numerical computing, Julia is unusually well-suited for expressing ML algorithms. Meanwhile, its mix of modern design and new ideas in the compiler makes it easier to address the high performance needs of cutting edge ML.

Where typical frameworks are all-encompassing monoliths in hundreds of thousands of lines of C++, Flux is only a thousand lines of straightforward Julia code. Simply take one package for gradients (Zygote.jl), one package for GPU support (CuArrays.jl), sprinkle with some light convenience functions, bake for fifteen minutes and out pops a fully-featured ML stack.