cmake-cookbook VS Fortran-code-on-GitHub

The hints in place ("there is more infrastructure already available outside Fortran, consider using them instead"). Beliavsky's compilation Fortran code on GitHub with its section about neural networks and machine learning still may be worth a visit e.g. how let Fortran reach out for the implementations in other languages.

There is an interesting directories compiled about projects around Fortran, Fortran code on GitHub. Though artificial intelligence does not appear by name, section Neural networks and Machine Learning may provide an entry.

My list of Fortran codes on GitHub has a section Containers and Generic Programming with some of the data structures you mention.

There's modern stuff being written in astro(nomy/physics) (I can attest to some of the codebases listed in https://github.com/Beliavsky/Fortran-code-on-GitHub#astrophy... being modern, at least in terms of development), but I'd say C++ likely does have the upper hand for newer codebases (unless things have changed dramatically last time I looked, algorithms that don't nicely align with nd-arrays are still painful in Fortran).

I've also heard rumours of Julia and even Rust being used (the latter because of the ability to reuse libraries in the browser e.g. for visualisation), but the writers of these codebases (and the Fortran/C/C++/Java) are unusual—Python and R (and for some holdouts, IDL) are what are most people write in (even if those languages call something else).

"QuantEcon:Open source code for economic modeling" https://quantecon.org/ has Python and Julia versions. The Federal Reserve uses Julia in its macroeconomic models: https://frbny-dsge.github.io/DSGE.jl/latest/ . Some economists use Fortran (which is much modernized since FORTRAN 77), and there is a 2018 book Introduction to Computational Economics using Fortran https://www.ce-fortran.com/ . Some Fortran codes in economics, statistics, and time series analysis are listed at https://github.com/Beliavsky/Fortran-code-on-GitHub .

At the "Fortran Code on GitHub" repo https://github.com/Beliavsky/Fortran-code-on-GitHub there are many codes listed in the "Climate and Weather" and "Earth Science" sections.

Fortran 77 and later versions (most recently Fortran 2018) have strings. There is the limitation that the elements of an array of strings must have equal length, so that ["boy","girl"] is invalid but ["boy ","girl"] is. Libraries for manipulating strings in Fortran are listed at https://github.com/Beliavsky/Fortran-code-on-GitHub#strings .