Fruzsina Julia Agocs

I'm a research fellow at the Center for Computational Mathematics within the Flatiron Insitute, working in the numerical analysis group led by Alex Barnett. My research blends scientific computing with numerical analysis and computational physics, and is guided by physics and engineering applications. My work includes developing high-order accurate, efficient numerical methods for challenging ordinary and partial differential equations (ODEs and PDEs), and inference of early-universe physics. Previously I've studied at the University of Cambridge, UK, where I earned my PhD in cosmology while being advised by Anthony Lasenby, Mike Hobson, and Will Handley. Before then, I did an MSci + BA in physics.
For details, see my CV: PDF

I'm passionate about bird conservation, birdwatching, and photography. I volunteer for the NYC Audubon Society in the Project Safe Flight collision monitoring project. This involves collecting data on birds that collided with windows in the city during migration season, and aims to use this to understand collision patterns and causes, as well as in advocacy work for bird-friendly building design. I rowed for my college team at uni, enjoy bouldering, hiking, and playing boardgames/RPGs.

Research

Scattering from periodic boundaries

I combined modern boundary integral equation methods with the Floquet--Bloch transform and complex analysis to develop the first fast and high-order accurate solver for scattering of a nonperiodic source from a periodic boundary.
Read more

Frequency-independent solvers for oscillatory ODEs

I developed fixed- and arbitrarily high-order methods for ODEs that adapt to the solution's behavior changing between rapidly oscillatory and smoothly varying. I also released open-source software implementations in C++/Python.
Read more

Initial conditions for quantum fluctuations during cosmic inflation

In this theoretical, quantum field theory-focused work I investigated methods by which one defines vacuum in a dynamic spacetime. This is then used to set initial conditions to quantum-scale perturbations during the early development of the Universe.
Read more

Computational cosmology

I'm also interested in exploring computationally intensive cosmological models of interest, such as closed universes and kinetic dominance.
Read more

Publications

1. Agocs, F. J.; Barnett, A. H., Trapped acoustic waves and raindrops: high-order accurate integral equation method for localized excitation of a periodic staircase, submitted to Journal of Computational Physics, 2023. arXiv
2. Agocs, F. J., riccati: an adaptive, spectral solver for oscillatory ODEs, Journal of Open-Source Software, 2023. DOI
3. Agocs, F. J.; Barnett, A. H., An adaptive spectral method for oscillatory second-order linear ODEs with frequency-independent cost", to appear in SIAM Numerical Analysis, 2022. arXiv
4. Letey, M. I.; Shumaylov, Z.; Agocs, F. J., Quantum initial conditions for curved inflating universes, submitted to Physical Review D, 2022. arXiv DOI
5. Hergt, L. T.; Agocs, F. J.; Handley, W. J.; Hobson, M. P.; Lasenby, A. N., Finite inflation in curved space, Physical Review D, 2022. arXiv DOI
6. AbdusSalam, S. S.; Agocs, F. J., et al., (the GAMBIT collaboration), Simple and statistically sound recommendations for analysing physical theories, Reports on Progress in Physics, 2022. arXiv DOI
7. Agocs, F. J.; Hobson, M. P.; Handley, W. J.; Lasenby, A. N., Dense output for highly oscillatory numerical solutions, submitted to Physical Review Research, 2020. arXiv
8. Agocs, F. J., (py)oscode: fast solutions of oscillatory ODEs, Journal of Open-Source Software, 2020. DOI
9. Agocs, F. J.; Hergt, L. T.; Lasenby, A. N.; Hobson, M. P., Quantum initial conditions for inflation and canonical invariance, Physical Review D, 2020. arXiv DOI
10. Agocs, F. J.; Handley, W. J.; Lasenby, A. N.; Hobson, M. P., Efficient method for solving highly oscillatory ordinary differential equations with applications to physical systems, Physical Review Research, 2020. arXiv DOI

Upcoming

• Jun 2024, Flatiron workshop on Computational tools for PDEs with complicated geometries and interfaces (organizing committee)
• Jul 2024, minisymposium on Integral equation and related methods for PDEs with complex geometries at SciCADE, Singapore

Past talks and posters

• Feb 2024, University of Marlyand, Baltimore County (invited colloquium)
• Nov 2023, University of Massachusetts Lowell (invited seminar)
• Oct 2023, SIAM-NNP, Newark (minisymposium, organizer)
• Oct 2023, Cornell (invited talk) video
• Aug 2023, ICIAM, Tokyo (contributed talk)
• Aug 2023, ICOSAHOM, Seoul (minisymposium), Reproducing the unique acoustics of periodic staircases using boundary integral equations slides
• May 2023, FACM (Frontiers in Applied and Computational Mathematics), New Jersey Institute of Technology poster
• Apr 2023, NYU, New York (invited seminar)
• Feb 2023, SIAM Computer Science and Engineering, Amsterdam (minisymposium, organizer)
• Feb 2023, Yale (invited seminar)
• Dec 2022, University of Innsbruck (invited seminar)
• Oct 2022, Flatiron-wide algorithms and mathematics, New York (lecture), Numerical solution of ODEs: a practical guide video
• Oct 2022, University of Chicago (invited seminar)
• Oct 2022, New Jersey Institute of Technology (invited seminar)
• Sept 2022, Sayas numerics day, University of Maryland, BC (contributed talk)
• Jun 2022, SDIDE, Budapest (invited speaker)
• May 2022, BIRS-CMO workshop on "Outstanding challenges in computational methods for integral equations", virtual (invited speaker)
• Jan 2021, CAM-LMU workshop, virtual (contributed talk)
• Nov 2020, Numerical analysis seminar, Flatiron Institute, New York
• July 2020, Beecroft Institute, University of Oxford (seminar)
• July 2020, SciPy conference, virtual (contributed talk), pyoscode: fast solution of oscillatory ODEs in physics video
• Apr 2020, Battcock Centre for Experimental Astrophysics, Cambridge (invited seminar)
• Jan 2020, Institute of Astronomy, Cambridge (invited seminar)
• Sept 2019, KICC10, Kavli Institute of Cosmology, Cambridge (contributed talk & poster)
• Oct 2018, Kavli Institute of Cosmology, Cambridge (invited seminar)
• Jul 2018, National CDT in data intensive science conference, London (poster)
• Jun 2017, Battcock Centre for Experimental Astrophysics, Cambridge (invited seminar)

Software

• riccati: a pure Python implementation of my arbitrarily high-order oscillatory ODE solver GitHub
• (py)oscode: a C++/Python package implementing a fixed-order oscillatory ODE solver GitHub

• GAMBIT: a collaborative project that combines particle physics (LHC) and cosmology data to investigate beyond-Standard Model theories GitHub

Teaching and mentoring

• supervisions (small group tutorials) in Math, General Relativity: 6 students, 56 hours;
• examples classes (large group tutorials) in Relativistic Astrophysics & Cosmology: 61 students, 39 hours;
• revision sessions in General Relativity.

Outreach and service

• Article on meteor showers (in Hungarian) link
• Institute of Astronomy Wednesday open evening talk video
• Periscope "Ask a physicist" Q+A video

• the SciPy conference
• JOSS - Journal of Open Source Software
• SINUM - SIAM Journal on Numerical Analysis
• JCAM - Journal of Computational and Applied Mathematics