by Ned Thaddeus Taylor
diffstruc is a Fortran library that provides automatic differentiation capabilities through use of an array derived type.
The library has implemented both forward and reverse mode automatic differentiation. Through repetitive use of the forward mode differentiation procedure, any higher order partial differentiation is achievable (note, memory usage will increase for higher order differentials) and has been tested up to third order.
diffstruc is distributed with the following directories:
| Directory | Description |
|---|---|
| docs/ | Compilable documentation |
| src/ | Source code |
| test/ | A set of unit test programs to check functionality of the library works after compilation |
Tutorials and documentation are provided on the docs website.
Refer to the API Documentation section later in this document to see how to access the API-specific documentation.
The diffstruc library can be obtained from the git repository. Use the following commands to get started:
git clone https://github.com/nedtaylor/diffstruc.git
cd diffstruc
The library has the following dependencies
- A Fortran compiler (compatible with Fortran 2018 or later)
- fpm
The library has been developed and tested using the following compilers:
- gfortran -- gcc 15.2.0
- ifx -- ifx 2025.2.0
NOTE: diffstruc is known to be incompatible with all versions of the gfortran compiler below
14.3.0due to issues with the calling of thefinalprocedure ofarray_type.
The library is set up to work with the Fortran Package Manager (fpm).
Run the following command in the repository main directory:
fpm build --profile release
To check whether diffstruc has installed correctly and that the compilation works as expected, the following command can be run:
fpm test
This runs a set of test programs (found within the test/ directory) to ensure the expected output occurs when layers and networks are set up.
API documentation can be generated using FORD (Fortran Documenter). The library has a compilable documentation this can be accessed with the FORD (FORtran Documenter) tool. The documentation can be compiled using the following terminal command in the root directory of the repository:
ford ford.md
This will generate the docs/html directory, inside which, you will find index.html.
By opening this file in a browser window, you will be able to view a nagivable documentation.
Please note that this project adheres to the Contributing Guide. If you want to contribute to this project, please first read through the guide.
This work is licensed under an MIT license.