DNAOAD (FPM Version)

Dual Numbers for Arbitrary Order Automatic Differentiation in Modern Fortran

This repository provides a Fortran Package Manager (fpm) compatible version of the dual number implementation for arbitrary-order automatic differentiation (DNAOAD).

⚠️ Note: The core code is essentially the same as in the original repository fpenunuri/DNAOAD, with some changes for FPM compatibility. For more information, see the preprint: 📄 arXiv:2501.04159

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📁 Project Structure

• src/ — Fortran source modules
• app/ — Executable programs
• docs/ — Documentation of module functions
• fpm.toml — Project configuration file

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📦 Requirements

• A Fortran compiler (e.g., gfortran, ifx)
• A recent version of fpm

To install fpm, visit:
👉 https://github.com/fortran-lang/fpm

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🛠️ Building with ifx (default: real64)

From the project root:

FPM_FC=ifx fpm build

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▶️ Running Examples

Example 1 (default real64, max order = 5)

FPM_FC=ifx fpm run ex1

Example 2 (requires higher order derivatives)

By default, MAX_ORDER_DUALZN = 5. The example ex2 requires at least 10:

FPM_FC=ifx fpm run --flag "-DMAX_ORDER_DUALZN=10" ex2

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⚙️ Using real128 Precision

To build and run using real128 precision:

FPM_FC=ifx fpm build --flag "-DUSE_REAL128"

Run ex2 with higher derivative order:

FPM_FC=ifx fpm run --flag "-DUSE_REAL128 -DMAX_ORDER_DUALZN=10" ex2