News

Everything, newest first

Releases of the code, the papers describing it, and results computed with it.

  • CLASS v3.4.0 has been merged into hi_class, released as v3.4.0.0. The Python wrapper hiclassy is also available on PyPI at v3.4.0.0. v3.4.0.0 · PyPI · Documentation

  • hi_class v3.3.4.4 was released, rebuilt on CLASS v3.3.4. The beyond-Horndeski (GLPV) and conformally coupled Galileon models are now part of the public code. hiclassy v3.3.4.4 was also published on PyPI: v3.3.4.4 · PyPI

  • Single Scalar Field Dark Energy: 2026 Status Report, a review talk on where the field stands, by Carlos García-García and William Wolf. video

  • Since 9 February 2026, the Python wrapper uses the names hiclassy and HiClass. To adapt a standard CLASS Python script, replace from classy import Class with from hiclassy import HiClass and instantiate HiClass() instead of Class(). The standard methods of the corresponding CLASS version are unchanged; additional methods expose modified-gravity quantities. The wrapper is available on PyPI via pip install hiclassy. PyPI

  • DESI put out modified-gravity constraints from the full-shape modelling of its 2024 clustering measurements, computed with hi_class. JCAP 09 (2025)

  • The Cosmological Evidence for Non-Minimal Coupling, whose modified-gravity predictions were computed with hi_class, appeared in Physical Review Letters. PRL 135 (2025)

  • hi_class 3.0 was released, rebuilt on CLASS v3.2.3. v3.0

  • The second hi_class paper, on background evolution, initial conditions and approximation schemes, appeared in JCAP 02 (2020) 008. arXiv:1909.01828

  • hi_class 2.0 was released alongside the preprint documenting how it solves the background, sets initial conditions and switches approximation schemes. v2.0 · arXiv:1909.01828

  • hi_class was registered in the Astrophysics Source Code Library, which is where a citation to the code itself points. ascl:1808.010

  • Comparison of Einstein-Boltzmann solvers for testing general relativity, which checks hi_class against the other codes used for modified gravity, appeared in Physical Review D: the CMB and matter power spectra agree at the sub-percent level. PRD 97 (2018) 023520

  • Dark Energy after GW170817: Dead Ends and the Road Ahead, on which theories survive the neutron-star merger's bound on the speed of gravity, appeared in Physical Review Letters. PRL 119 (2017) 251304 · Physics Viewpoint

  • The paper introducing the code appeared in JCAP 08 (2017) 019. JCAP 1708 (2017) 019

  • hi_class 1.1 generalised the parametrizations: the two Planck ones gave way to power-law and exponential forms, in both the α and the EFT γ bases, including the case used in the comparison of Einstein-Boltzmann solvers. v1.1

  • First public release, together with the preprint introducing hi_class: Horndeski's theory in the Cosmic Linear Anisotropy Solving System. v1.0 · arXiv:1605.06102

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