I am experimenting with OpenAI Codex CLI to generate Fortran programs. It runs on Unix-like terminals and also the Windows terminal. If you give it full access (set under /approvals), which I did, and have gfortran, ifx, Fortitude, and FORD installed, Codex will iterate until the program compiles and runs and passes fortitude check and create documentation using FORD. A program to fit autoregressive models of various orders (inspired by @aledinola) and choose the AR order according to information criteria is at GitHub - Beliavsky/Autoregression: Use OpenAI Codex to create a Fortran program to fit univariate autoregressive time series models .
Codex took about 15 minutes to create a working program, without any user interaction. So if you are willing to wait while Codex runs unattended, you don’t need to send compiler or Fortitude messages back to ChatGPT until code compiles cleanly – this is done internally by Codex. After telling Codex what the program should do, the prompt has the following instructions:
Add brief comments within the main program and each procedure explaining what they do. Format the comments so that the FORD tool can produce documentation from them.
Use !! for documentation comments attached to the nearest code element
(module, submodule, procedure, variable) that precedes the comment
line.
Place !! comments on the same line as a declaration or on following
lines immediately after the declaration.
For multi-line doc blocks, start with !!* and then continue the block
with single-bang ! lines; they’ll be joined to the same doc block.
Assume that the gfortran compiler is installed. Use the compiler options
-O0 -Wall -Werror=unused-parameter -Werror=unused-variable -Werror=unused-function -Wno-maybe-uninitialized -Wno-surprising -fbounds-check -static -g -fmodule-private
Verify that program also compiles and runs with the ifx compiler using the options
/nologo /traceback /check:bounds /check:uninit /warn:all /warn:unused /gen-interfaces /warn:interfaces /F512000000
Create a batch file compile.bat that compiles the source files into executables using gfortran and ifx.
To check style, run fortitude check foo.f90 for each source file foo.f90 you create after you verify that it compiles. Leave the executables created by the compilers in the current directory.
Create a new git repository and commit source files to git once they
compile and run properly. Assume git commands are available.
Once the code is finished, use ford to create documentation from the comments
you have embedded in the code.
If any of gfortran, ifx, ford, fortitude, or git are unavailable, give an error message and quit.