Floating-point consistent cross-verification methodology for reproducible and interoperable DDA solvers with fair benchmarking

TL;DR

This paper presents a unified methodology for cross-verification and benchmarking of DDA solvers to ensure reproducibility, interoperability, and accurate performance comparisons across different implementations and hardware architectures.

Contribution

It introduces a software-assisted approach for aligning parameters and achieving machine-precision agreement among major open-source DDA solvers, facilitating reproducible and fair benchmarking.

Findings

Achieved machine-precision agreement across DDSCAT, ADDA, and IFDDA.

Provided practical equivalence tables for consistent DDA simulations.

Performed systematic CPU and GPU performance comparisons.

Abstract

The discrete dipole approximation (DDA) is a widely used and versatile numerical method for solving electromagnetic scattering by arbitrarily shaped objects. Despite its popularity, quantitative comparisons between independent implementations remain challenging due to differences in linear-system conventions, solver settings, and default numerical parameters. In this work, we introduce a unified software-assisted methodology for cross-verification and benchmarking of three major open-source DDA solvers: DDSCAT, ADDA, and IFDDA. We demonstrate how machine-precision agreement can be achieved across implementations by aligning all free parameters and provide practical equivalence tables enabling reproducible and interoperable simulations. Using this methodology, we perform systematic CPU and GPU performance comparisons covering OpenMP, MPI, and CUDA/OpenCL parallelization. Beyond benchmarking, our approach serves as a practical guide for configuring consistent DDA simulations and for understanding how precision, solver choice, and hardware architecture affect runtime, scalability, and accuracy in computational light-scattering studies. The software package also supports regression testing and bitwise reproducibility verification for future code releases.