GInX: A Geodesics Integrator tool for particles in GRMHD using Adaptive Mesh Refinement

The integration of null geodesic equations within the 3+1 formalism of general relativity plays a key role in the process of computing images via ray tracing and analyzing spectra in GRMHD simulations. The objective of this project is to develop a geodesic integrator for particles in a generic GRMHD background using the Fast-Light approximation with Adaptive Mesh Refinement (AMR), and to accelerate the integration with GPU computing. The implementation will utilize the C++ programming language in conjunction with the AMReX framework, which has been built with GPU support enabled. The project will focus both on the accurate numerical integration of null geodesic and on evaluating GPU-accelerated performance. The purpose of this tool is to serve as a post-processing module for the visualization and analysis of GRMHD simulation data. Additionally, it represents a critical first step toward the development of a full Monte Carlo radiation transport code, where fast and efficient geodesic integration is essential.