Indonesian Journal of Applied Mathematics
Vol. 6 No. 1 (2026): Indonesian Journal of Applied Mathematics Vol. 6 No. 1 April Chapter

amangkurat: A Python library for symplectic pseudo-spectral solution of the idealized (1+1)D nonlinear Klein-Gordon equation

Sandy Hardian Susanto Herho (University of California, Riverside)
Siti Kaban (WorldQuant University)



Article Info

Publish Date
30 Apr 2026

Abstract

This study introduces amangkurat, an open-source Python library designed for the robust numerical simulation of relativistic scalar field dynamics governed by the nonlinear Klein-Gordon equation in (1 + 1)D spacetime. The software implements a hybrid computational strategy that couples Fourier pseudo-spectral spatial discretization with a symplectic Størmer-Verlet temporal integrator, ensuring both exponential spatial convergence for smooth solutions and long-term preservation of Hamiltonian structure. To optimize performance, the solver incorporates adaptive timestepping based on Courant-Friedrichs-Lewy (CFL) stability criteria and utilizes Just-In-Time (JIT) compilation for parallelized force computation. The library’s capabilities are validated across four canonical physical regimes: dispersive linear wave propagation, static topological kink preservation in phi-fourth theory, integrable breather dynamics in the sine-Gordon model, and non-integrable kink-antikink collisions. Beyond standard numerical validation, this work establishes a multi-faceted analysis framework employing information-theoretic entropy metrics (Shannon, Rényi, and Tsallis), kernel density estimation, and phase space reconstruction to quantify the distinct phenomenological signatures of these regimes. Statistical hypothesis testing confirms that these scenarios represent statistically distinguishable dynamical populations. Benchmarks on standard workstation hardware demonstrate that the implementation achieves high computational efficiency, making it a viable platform for exploratory research and education in nonlinear field theory.

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Journal Info

Abbrev

indojam

Publisher

Subject

Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Economics, Econometrics & Finance Physics

Description

Indonesian Journal of Applied Mathematics is a scientific publication media that publishes articles from the results of research or studies in the field of applied mathematics, focusing on Computational Mathematics, Optimization, Actuarial, Statistics, Numerical Modelling, Mathematical Physics, ...