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REVIEW 3 major objections 6 minor 1 cited by

TempLat lets you write lattice field equations almost as math and compiles them into fast kernels that scale on CPUs and GPUs in any dimension.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

T0 review · grok-4.5

2026-07-31 05:59 UTC pith:ZNMRP37G

load-bearing objection Solid open-source lattice engine with real GPU CosmoLattice path and honest HILA/cuFFTMp baselines; “excellent multi-node GPU scaling” is real in the tested regime but geometry-limited at high rank. the 3 major comments →

arxiv 2607.24908 v1 pith:ZNMRP37G submitted 2026-07-27 hep-lat astro-ph.COcond-mat.stat-mechhep-ph

TempLat: a versatile C++ engine for lattice field theories

classification hep-lat astro-ph.COcond-mat.stat-mechhep-ph
keywords lattice field theoryexpression templatesperformance portabilityGPU computingparallel FFTclassical-statistical simulationsgauge fieldshybrid MPI
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

Lattice field theory underpins early-universe dynamics, critical phenomena, and non-perturbative particle physics, but high-performance codes are usually specialized and hard for non-experts to extend. This paper presents TempLat, a C++ engine whose expression-template language turns continuum equations into nearly verbatim code that fuses into single optimized kernels at compile time. Hardware is abstracted as a device, so the same source targets large CPU clusters and NVIDIA and AMD GPUs, with automatic halo updates and Fourier transforms. The authors also ship ParaFaFT, a portable parallel FFT library for arbitrary dimensions, and show strong and weak scaling on both CPUs and GPUs. Together they power a GPU-capable release of a widely used early-universe lattice code, aiming to make portable lattice simulation accessible beyond specialists.

Core claim

TempLat is a versatile, dimension-agnostic C++ lattice engine: expression templates map mathematical field equations almost verbatim into C++ while fusing them into highly optimized device kernels, and a Kokkos-backed host/device model delivers performance-portable classical-statistical and related lattice simulations with excellent strong and weak scaling on CPUs and on NVIDIA and AMD GPUs, accompanied by the standalone arbitrary-dimension parallel DFT library ParaFaFT.

What carries the argument

Expression templates over lattice fields: an abstract expression tree is built at compile time, pruned (e.g. by ZeroType/OneType), then fused into a single kernel and dispatched via a device iteration/reduce API, with automatic halo exchanges and DFTs inferred from the tree.

Load-bearing premise

The claim of excellent scaling at large GPU counts assumes that the pencil domain split and current halo-exchange strategy stay adequate even when each device holds little volume and network traffic dominates.

What would settle it

Repeat the paper’s SU(2) and scalar leapfrog weak/strong scaling on the same A100-class nodes but with a full multi-dimensional block decomposition and non-blocking halo overlap; if per-site time then rises sharply or falls behind a block-decomposed baseline at high GPU count while kernels stay flat, the scaling claim is geometry-limited as the paper’s own comparison already hints.

Watch this falsifier — get emailed when new claim-graph text bears on it.

If this is right

  • The same source can target CPU clusters and NVIDIA/AMD GPUs without rewriting lattice physics expressions.
  • Cosmology and other classical lattice apps built on this engine gain a GPU path with automatic FFTs and ghost updates.
  • New composite types (e.g. further gauge groups) can be added by supplying their algebra, reusing the same evaluation and device layer.
  • ParaFaFT fills a gap for distributed, arbitrary-dimension DFTs across the supported hardware backends.
  • Cross-checks against an independent portable lattice engine become practical on identical workloads.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Decoupling real-space domain layout from FFT layout, as the authors flag, is likely the highest-leverage fix when FFTs or high-rank halos dominate.
  • The compile-time algebra and device split are a natural base for a Monte Carlo or semiclassical-fermion layer once those algebras land.
  • Accessibility for non-specialists will hinge as much on docs and model packs as on kernel speed once GPUs are routine.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

3 major / 6 minor

Summary. The paper presents TempLat, an open-source C++ lattice field theory framework built on expression templates with a Kokkos-based device abstraction (CPU via OpenMP/pthreads, NVIDIA via CUDA, AMD via HIP), together with ParaFaFT, a standalone distributed DFT library supporting arbitrary dimensions via pencil decomposition. The interface and architecture are described in §§2–3; §4 reports strong and weak scaling for an SU(2) Yang–Mills leapfrog benchmark on the Otus (EPYC) and Noctua2 (A100) clusters, including per-phase (halo/kick/drift) timing breakdowns, and a cross-validation against HILA on a scalar φ⁴ kernel. Appendix A benchmarks ParaFaFT against FFTW3-MPI and cuFFTMp. The manuscript is clearly written, the code and tests are public, and the limitations (pencil-decomposition halo growth, GPU-count-dependent competitiveness vs HILA and cuFFTMp) are reported frankly. My concerns are local: the headline scaling claim needs scoping, benchmark reproducibility details are missing, and one scaling argument in §4 is asserted rather than shown.

Significance. If the results hold as reported — and there is little reason to doubt the measurements — TempLat is a useful contribution: an open-source, expression-template lattice engine with Kokkos-based CPU/NVIDIA/AMD portability, plus ParaFaFT, which to my knowledge is the only distributed DFT library combining arbitrary dimensionality with cross-vendor performance portability. Specific strengths worth naming: (i) both codes are open source with unit-test coverage and reproducible counter-based RNG; (ii) the performance claims are substantiated with strong/weak scaling on two real clusters with per-phase (halo/kick/drift) breakdowns; (iii) an independent cross-check against HILA on an identical φ⁴ workload is rare and valuable practice; (iv) limitations (halo cost growing ~P^{1/2} vs the ideal P^{1/6}; ParaFaFT trailing cuFFTMp at small GPU counts) are disclosed and analyzed rather than hidden. The gap between pencil and block decompositions is honestly identified as the main scaling risk.

major comments (3)
  1. [Abstract and §5, vs. Fig. 6 and Appendix A] The abstract and §5 state 'excellent strong and weak scaling on both CPUs and GPUs' without qualification, but the paper's own results bound the regime in which this holds: Fig. 6 (left) shows HILA overtaking TempLat in strong scaling at high GPU counts (attributed to HILA's d-dimensional block vs TempLat's pencil decomposition), and Fig. 7 (right) shows ParaFaFT behind cuFFTMp at smaller GPU lattices. The body text discusses these limitations honestly and well; the problem is only that the headline claim does not reflect them. Please qualify the abstract/conclusion claim to the demonstrated regime (workload-rich runs, up to 32 A100s / 3072 CPU ranks) rather than asserting scaling 'excellence' generally.
  2. [§4 and Appendix A] The performance claims of §4 are the paper's central deliverable, but the manuscript gives no compiler versions, Kokkos/CUDA/HIP/MPI versions, or build flags, and does not state whether the benchmark harness (run scripts, job configurations) is shipped in the GitHub repositories. For a software/performance paper, these are needed for the results to be independently checkable. Relatedly, the abstract claims AMD GPU (HIP) support as part of performance portability, yet no AMD benchmark or even a validation result is shown — all GPU data are A100. Please either add an AMD data point or state explicitly that HIP support is validated by unit tests only, with performance numbers deferred.
  3. [§4, Fig. 5 discussion] The text derives an ideal weak-scaling halo cost per site of O(P^{1/6}) but reports measured growth 'closer to O(P^{1/2})', attributed to 'non-square decompositions and additional synchronization overhead'. This is a large gap asserted without quantitative support: over only 8 points spanning 1–32 GPUs (with node-boundary effects at 4), a P^{1/2} fit is weakly constrained, and the residual communication model in the HILA discussion (4N²P^{1/2} at fixed N) is not obviously consistent with the weak-scaling per-site statement. Please either provide a quantitative decomposition (e.g., measured surface-to-volume scaling for the actual rank grids used, or a sync-vs-transfer split) or present the P^{1/2} statement as an empirical observation over the tested range only.
minor comments (6)
  1. [§2, Listing 1 and Eq. (1)] Listing 1: the noise is rescaled by 1/sqrt(dt) 'to get the correct dt->0 limit', but the fluctuation-dissipation normalization (factor of 2T in <eta eta>) is silently absorbed. One sentence on the assumed temperature/normalization would help readers reuse the example.
  2. [Fig. 3 and Fig. 4] The labels '78%', '75%', '61%' (and Fig. 4's 96/87/82/78%) appear to annotate parallel efficiency at selected points, but this is never stated in the captions. Please define them.
  3. [Listing 2] 'SessionGuard' appears without explanation; a half-sentence (RAII initialization/finalization of MPI and Kokkos) would suffice.
  4. [References] Reference [21] is a bare GitHub URL dated 2026. If a citable HILA publication or release note exists it should be used; at minimum cite a tagged release/commit so the comparison version is pinned. The HILA compiler/flags used for Fig. 6 should also be stated.
  5. [Appendix A] Fig. 7, right panel: 'we equate one CPU node with a single GPU' for the shared x-axis is easy to misread as a performance equivalence claim; please clarify in the caption that it is only an axis alignment.
  6. [§2, Table 1] Table 1 describes U1Field as an alias of ComplexField; it would be worth one sentence noting whether U(1) assignments are projected to unit modulus or left to the user, since this affects physical correctness in gauge applications.

Circularity Check

0 steps flagged

No circularity: software/benchmark paper with measured timings and external baselines, not definitional or fitted predictions.

full rationale

TempLat is a methods/software paper. Its central claims are (i) an expression-template + Kokkos device abstraction that compiles mathematical lattice expressions to portable kernels, and (ii) measured strong/weak scaling on CPUs and GPUs, plus ParaFaFT DFT scaling versus FFTW-MPI and cuFFTMp. Performance numbers are wall-clock timings of fixed leapfrog workloads (SU(2) Yang–Mills and φ⁴), not quantities derived from fitted parameters or from definitions that already encode the result. Self-references to CosmoLattice establish lineage (TempLat as its former engine) and do not load-bear the scaling claims. Cross-checks against independent HILA and vendor FFT libraries are external evidence. Domain decomposition inherited from ParaFaFT affects absolute halo cost and is disclosed analytically (O(P^{1/6}) ideal vs measured growth), but that is a limitation of the design choice, not a circular reduction of a claimed derivation. No self-definitional loop, fitted-input-as-prediction, uniqueness import, or renamed empirical law appears in the derivation chain.

Axiom & Free-Parameter Ledger

0 free parameters · 5 axioms · 2 invented entities

As a systems/methods paper, load-bearing premises are standard HPC and lattice-practice assumptions plus engineering choices (Kokkos portability, pencil FFT decomposition, expression-template fusion), not fitted physical constants. No new physical entities are postulated.

axioms (5)
  • domain assumption Kokkos correctly and performantly maps the TempLat device iteration/memory API onto CUDA, HIP, OpenMP, pthreads, and serial backends.
    Entire performance-portability claim in §3 rests on Kokkos; benchmarks assume this mapping is not the hidden bottleneck.
  • ad hoc to paper Pencil domain decomposition (keep one axis local, segment d−1) is an acceptable default for both real-space halo exchange and distributed DFTs across the reported rank counts.
    Stated in §4 and Appendix A; authors note HILA’s block decomposition and cuFFTMp slabs can win in some regimes.
  • domain assumption Classical leapfrog SU(2) Yang–Mills and φ⁴ kernels with one ghost layer and double precision are representative workloads for claiming general lattice-engine efficiency.
    §4 benchmark design; exercises algebra, halos, and communication but not full Monte Carlo or fermions.
  • domain assumption Expression-template full-tree fusion at assignment yields a single device kernel without harmful register/spilling regressions relative to hand-written kernels on target GPUs.
    Core optimization argument in §3.4; supported indirectly by timings, not by compiler IR audits.
  • standard math Standard lattice finite differences, periodic boundaries, and MPI halo semantics correctly implement the continuum-intended operators used in the examples.
    Background lattice field theory practice assumed throughout §§2–4.
invented entities (2)
  • TempLat framework (expression-template lattice algebra + device abstraction) independent evidence
    purpose: Provide portable, math-like API and optimized kernels for lattice simulations across CPU/GPU.
    Software artifact introduced and released; not a physical entity. Independent evidence is the public repo and benchmarks.
  • ParaFaFT parallel DFT library independent evidence
    purpose: Supply arbitrary-dimension hybrid-parallel r2c/c2r transforms on CPU and AMD/NVIDIA GPUs where existing libraries are vendor- or dimension-limited.
    New library based on known pencil/transpose algorithms; validated against FFTW-MPI and cuFFTMp in Appendix A.

pith-pipeline@v1.2.0-grok45-kimik3 · 21645 in / 3207 out tokens · 68779 ms · 2026-07-31T05:59:36.579519+00:00 · methodology

0 comments
read the original abstract

We present TempLat, a C++ framework for lattice field theory simulations in arbitrary dimensions. Its symbolic language, built on expression templates, translates mathematical expressions almost verbatim into C++ while compiling to highly optimized kernels, in contexts ranging from classical-statistical to Monte Carlo simulations. TempLat is performance-portable: building on Kokkos, it supports large CPU clusters, as well as NVIDIA and AMD GPUs. Its abstraction of hardware into a device concept makes TempLat extensible to future architectures. We demonstrate excellent strong and weak scaling on both CPUs and GPUs. We also present ParaFaFT, a standalone parallel discrete Fourier transform library supporting arbitrary dimensions on all of the above hardware, and benchmark its scaling. Both are open source and available on GitHub, and power a new release of CosmoLattice, a widely used early-universe simulation library now available on GPUs.

Figures

Figures reproduced from arXiv: 2607.24908 by Adrien Florio, Franz R. Sattler.

Figure 1
Figure 1. Figure 1: Hybrid parallelization structure lattice simulations, the overall simulation domain can be cleanly split between nodes. The only necessary memory exchange is that of boundary cells, allowing the represen￾tation of interactions between nearest neighbors or even at larger distances. This mode of parallelization is necessary to scale up to large HPC clusters, in which hundreds or even thousands of nodes can w… view at source ↗
Figure 2
Figure 2. Figure 2: Left: Cached memory access: each thread gets a block of memory it walks through, allowing it to both cache the memory and enable SIMD. Right: Coalesced memory access, where a warp of threads walks through the memory. Each thread in the warp thus has a fixed stride when iterating. For illustration we show warp sizes of 8, but NVIDIA hardware typically has warp sizes of 32, while AMD wavefronts are 32 or 64 … view at source ↗
Figure 3
Figure 3. Figure 3: Strong (left) and weak (right) scaling behavior of TempLat on the CPU partition of the Otus cluster. 10 −2 10 −1 seconds / step grid N 576³ 1152³ 1 2 4 8 12 16 24 32 GPUs 0.0 0.5 1.0 parallel e fficiency 1 2 4 8 12 16 24 32 lattice size / GPUs 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 ns / local site / step 384³ 404³ 508³ 640³ 732³ 800³ 912³ 1024³ ideal (flat from 1 GPU) 96% 87% 82% 78% node boundary → ¼ ½ 1 2 3… view at source ↗
Figure 4
Figure 4. Figure 4 [PITH_FULL_IMAGE:figures/full_fig_p008_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Decomposition of a single step in the 𝑆𝑈(2) benchmarks of the weak-scaling plot of fig. 4. Kick and drift show optimal behavior — their cost per site stays constant. The halo cost, in contrast, grows with the number of GPUs, since dividing the lattice further increases the surface-to￾volume ratio of each local domain. nanoseconds), which is directly comparable across lattice sizes. We also measure each of … view at source ↗
Figure 6
Figure 6. Figure 6: Strong (left) and weak (right) scaling behavior of TempLat and HILA on the A100 GPUs of the Noctua2 cluster. For this scaling analysis we use a classical relativistic scalar theory, evolved with a leapfrog algorithm. While we see very similar scaling curves for TempLat and HILA, in strong scaling we find that at high GPU counts, the block decomposition of HILA seems to scale better than the pencil decompos… view at source ↗
Figure 7
Figure 7. Figure 7: Strong scaling behavior of ParaFaFT on the Noctua2 cluster, for three-dimensional r2c+c2r transforms. Left: CPU runs with pure MPI parallelization. Middle: CPU runs with hybrid MPI+OpenMP parallelization. Right: GPU runs on A100s. In each panel ParaFaFT (solid) is compared against the corresponding baseline (dashed), i.e. MPI-parallel FFTW3 on CPU and cuFFTMp on GPU. Dotted lines indicate ideal scaling. to… view at source ↗

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Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. The art of simulating the early Universe. Part III: Scalar-Gauge-Fluid Dynamics

    astro-ph.CO 2026-07 accept novelty 5.0

    Detailed continuum-to-lattice schemes are given for perfect/imperfect fluids alone or coupled to scalars/gauges in FLRW, enabling self-consistent CosmoLattice simulations of early-Universe plasma dynamics and GWs.

Reference graph

Works this paper leans on

32 extracted references · 2 canonical work pages · cited by 1 Pith paper

  1. [1]

    G. I. Egri, Z. Fodor, C. Hoelbling, S. D. Katz, D. Nogradi, K. K. Szabo, Lattice QCD as a video game, Comput. Phys. Commun. 177 (2007)631–639.arXiv:hep-lat/0611022,doi:10.1016/j.cpc.2007.06. 005

  2. [2]

    M. A. Clark, R. Babich, K. Barros, R. C. Brower, C. Rebbi, Solving Lattice QCD systems of equations using mixed precision solvers on GPUs, Comput. Phys. Commun. 181 (2010) 1517–1528.arXiv: 0911.3191,doi:10.1016/j.cpc.2010.05.002

  3. [3]

    Lüescher, S

    M. Lüescher, S. Schaefer, Openqcd,https://luscher.web.cern.ch/ luscher/openQCD/

  4. [4]

    Sexty, Simulating full QCD at nonzero density using the complex Langevin equation, Phys

    D. Sexty, Simulating full QCD at nonzero density using the complex Langevin equation, Phys. Lett. B 729 (2014) 108–111.arXiv:1307. 7748,doi:10.1016/j.physletb.2014.01.019

  5. [5]

    arXiv:1512.03487,doi:10.22323/1.251.0023

    P.Boyle,G.Cossu,A.Yamaguchi,A.Portelli,Grid:Anextgeneration data parallel C++ QCD library, PoS LATTICE2015 (2016) 023. arXiv:1512.03487,doi:10.22323/1.251.0023

  6. [6]

    Altenkort, D

    L. Altenkort, D. Bollweg, D. A. Clarke, O. Kaczmarek, L. Mazur, C. Schmidt, P. Scior, H.-T. Shu, HotQCD on multi-GPU Systems, PoS LATTICE2021 (2022) 196.arXiv:2111.10354,doi:10.22323/1. 396.0196

  7. [7]

    Mazur, et al., SIMULATeQCD: A simple multi-GPU lattice code for QCD calculations, Comput

    L. Mazur, et al., SIMULATeQCD: A simple multi-GPU lattice code for QCD calculations, Comput. Phys. Commun. 300 (2024) 109164. arXiv:2306.01098,doi:10.1016/j.cpc.2024.109164

  8. [8]

    Laizet, N

    S. Laizet, N. Li, Incompact3d: A powerful tool to tackle turbu- lence problems with up to o(105) computational cores, International Journal for Numerical Methods in Fluids 67 (11) (2011) 1735– 1757.arXiv:https://onlinelibrary.wiley.com/doi/pdf/10.1002/fld. 2480,doi:https://doi.org/10.1002/fld.2480. URLhttps://onlinelibrary.wiley.com/doi/abs/10.1002/fld.2480

  9. [9]

    Open Source Softw

    A.Brandenburg,etal.,ThePencilCode,amodularMPIcodeforpar- tial differential equations and particles: multipurpose and multiuser- maintained, J. Open Source Softw. 6 (58) (2021) 2807.arXiv:2009. 08231,doi:10.21105/joss.02807

  10. [10]

    J. M. Stone, K. Tomida, C. J. White, K. G. Felker, The athena++ adaptive mesh refinement framework: Design and magnetohydrody- namic solvers, The Astrophysical Journal Supplement Series 249 (1) (2020) 4.doi:10.3847/1538-4365/ab929b. URLhttps://doi.org/10.3847%2F1538-4365%2Fab929b

  11. [11]

    Bruckner, S

    F. Bruckner, S. Koraltan, C. Abert, D. Suess, magnum.np – a py- torchbasedgpuenhancedfinitedifferencemicromagneticsimulation framework for high level development and inverse design (2023). arXiv:2302.08843. URLhttps://arxiv.org/abs/2302.08843

  12. [12]

    Vansteenkiste, J

    A. Vansteenkiste, J. Leliaert, M. Dvornik, M. Helsen, F. Garcia-Sanchez, B. Van Waeyenberge, The design and verification of mumax3, AIP Advances 4 (10) (2014) 107133. arXiv:https://pubs.aip.org/aip/adv/article-pdf/doi/10.1063/1. 4899186/12878560/107133_1_online.pdf,doi:10.1063/1.4899186. URLhttps://doi.org/10.1063/1.4899186

  13. [13]

    Piñeiro Orioli, K

    A. Piñeiro Orioli, K. Boguslavski, J. Berges, Universal self-similar dynamics of relativistic and nonrelativistic field theories near non- thermal fixed points, Phys. Rev. D 92 (2) (2015) 025041.arXiv: 1503.02498,doi:10.1103/PhysRevD.92.025041

  14. [14]

    D. G. Figueroa, A. Florio, F. Torrenti, W. Valkenburg, The art of simulating the early Universe – Part I: Integration techniques and canonicalcases,JCAP04(2021)035.arXiv:2006.15122,doi:10.1088/ 1475-7516/2021/04/035

  15. [15]

    Baeza-Ballesteros, D

    J. Baeza-Ballesteros, D. G. Figueroa, A. Florio, J. Lizarraga, N. Loayza, K. Marschall, T. Opferkuch, B. A. Stefanek, F. Torrentí, A. Urio, The art of simulating the early Universe. Part II. Non- canonical cases & gravitational waves (12 2025).arXiv:2512.15627

  16. [16]

    D.G.Figueroa,A.Florio,F.Torrenti,W.Valkenburg,CosmoLattice: A modern code for lattice simulations of scalar and gauge field dynamics in an expanding universe, Comput. Phys. Commun. 283 (2023) 108586.arXiv:2102.01031,doi:10.1016/j.cpc.2022.108586

  17. [17]

    D. G. Figueroa, A. Florio, F. Torrenti, Present and future ofosmo attice, Rept. Prog. Phys. 87 (9) (2024) 094901.arXiv:2312.15056, doi:10.1088/1361-6633/ad616a

  18. [18]

    H. C. Edwards, C. R. Trott, D. Sunderland, Kokkos: Enabling manycore performance portability through polymorphic memory access patterns, Journal of Parallel and Distributed Computing 74 (12) (2014) 3202 – 3216, domain-Specific Languages and High-Level Frameworks for High-Performance Computing. doi:https://doi.org/10.1016/j.jpdc.2014.07.003. URLhttp://www....

  19. [19]

    Trott, L

    C. Trott, L. Berger-Vergiat, D. Poliakoff, S. Rajamanickam, D.Lebrun-Grandie,J.Madsen,N.AlAwar,M.Gligoric,G.Shipman, G.Womeldorff,Thekokkosecosystem:Comprehensiveperformance portability for high performance computing, Computing in Science Engineering 23 (5) (2021) 10–18.doi:10.1109/MCSE.2021.3098509

  20. [20]

    C. R. Trott, D. Lebrun-Grandié, D. Arndt, J. Ciesko, V. Dang, N. Ellingwood, R. Gayatri, E. Harvey, D. S. Hollman, D. Ibanez, N. Liber, J. Madsen, J. Miles, D. Poliakoff, A. Powell, S. Rajaman- ickam, M. Simberg, D. Sunderland, B. Turcksin, J. Wilke, Kokkos 3: Programming model extensions for the exascale era, IEEE Trans- actions on Parallel and Distribut...

  21. [21]

    HILA, Hila,https://github.com/CFT-HY/HILA(2026)

  22. [22]

    Correia, M

    J. Correia, M. Hindmarsh, J. Lizarraga, A. Lopez-Eiguren, K. Rum- mukainen, J. Urrestilla, Scaling density of axion strings in terasite simulations, Phys. Rev. D 111 (6) (2025) 063532.arXiv:2410.18064, doi:10.1103/PhysRevD.111.063532

  23. [23]

    Rummukainen, private communication (2026)

    K. Rummukainen, private communication (2026)

  24. [24]

    URLhttps://doi.org/10.1145/2063384.2063405

    J.K.Salmon,M.A.Moraes,R.O.Dror,D.E.Shaw,Parallelrandom numbers: as easy as 1, 2, 3, in: Proceedings of 2011 International Conference for High Performance Computing, Networking, Storage and Analysis, SC ’11, Association for Computing Machinery, New York, NY, USA, 2011.doi:10.1145/2063384.2063405. URLhttps://doi.org/10.1145/2063384.2063405

  25. [25]

    A.Ayala,S.Tomov,A.Haidar,J.Dongarra,heffte:Highlyefficientfft for exascale, in: V. V. Krzhizhanovskaya, G. Závodszky, M. H. Lees, J. J. Dongarra, P. M. A. Sloot, S. Brissos, J. Teixeira (Eds.), Com- putational Science – ICCS 2020, Springer International Publishing, Cham, 2020, pp. 262–275

  26. [26]

    URLhttp://arxiv.org/abs/1804.09536

    L.Dalcín,M.Mortensen,D.E.Keyes,Fastparallelmultidimensional FFT using advanced MPI, CoRR abs/1804.09536 (2018).arXiv: 1804.09536. URLhttp://arxiv.org/abs/1804.09536

  27. [27]

    Program Generation, Optimization, and Platform Adaptation

    M. Frigo, S. G. Johnson, The design and implementation of FFTW3, Proceedings of the IEEE 93 (2) (2005) 216–231, special issue on “Program Generation, Optimization, and Platform Adaptation”

  28. [28]

    NVIDIA Corporation, cufft,https://developer.nvidia.com/cufft, nVIDIA CUDA Toolkit (2024)

  29. [29]

    AMD Corporation, hipfft,https://github.com/ROCm/hipFFT, aMD ROCm HIP FFT Library (2024)

  30. [30]

    Ehtesabi, M

    S. Ehtesabi, M. Hossain, T. Kenter, A. Krawinkel, H. Nitsche, L. Os- termann, C. Plessl, H. Riebler, S. Rohde, R. Schade, M. Schwarz, J. Simon, N. Winnwa, A. Wiens, X. Wu, Otus Supercomputer, PC2 Technical Report PC2TR-2025-1, Paderborn Center for Par- allel Computing (PC2), Paderborn, Germany, available at pc2.uni- paderborn.de/research/pc2-technical-rep...

  31. [31]

    Bauer, T

    C. Bauer, T. Kenter, M. Lass, L. Mazur, M. Meyer, H. Nitsche, H. Riebler, R. Schade, M. Schwarz, N. Winnwa, A. Wiens, X. Wu, C. Plessl, J. Simon, Noctua 2 supercomputer, Journal of large-scale research facilities JLSRF 9 (2024).doi:https://doi.org/10.17815/ jlsrf-8-187

  32. [32]

    G.Aarts,J.Smit,Realtimedynamicswithfermionsonalattice,Nucl. Phys. B 555 (1999) 355–394.arXiv:hep-ph/9812413,doi:10.1016/ S0550-3213(99)00320-X. A. Florio and F. R. Sattler:Preprint submitted to ElsevierPage 12 of 12