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PySCF vs iris

A side-by-side editorial comparison of PySCF and iris — release velocity, themes, recent moves, and the top alternatives to consider.

PySCF vs iris: at a glance

FeaturePySCFiris
SectorAnalyticsAnalytics
Velocity score2.52.5
Sparks · 30d00
Top themesquantum-chemistry, periodic-systems, coupled-cluster, gpu-accelerationearth science, release cadence, python, release candidates
Last editorial update1d ago2h ago
WebsiteVisit →Visit →

What is PySCF?

Quantum chemistry package adding whole method families every release.

PySCF is a Python-based quantum chemistry toolkit, and its release cadence is unusually feature-dense: each version lands multiple new electronic-structure methods rather than polishing existing ones. Recent releases have built out the GW/BSE excited-state stack, k-point RPA for periodic systems, higher-order coupled cluster, and multi-state PDFT with analytical gradients. Platform work runs alongside — Windows DLL compatibility, GPU4PySCF interfacing, and configurable einsum backends.

Read the full PySCF trajectory →

What is iris?

Iris ships steadily on a two-a-year cadence, but its feed publishes only pointers.

Iris tags a release candidate roughly every four to five months — 3.13 through 3.16 over the past year — and the cadence is the only thing the feed actually reports. Every entry is the same seven-line template: a line saying this is a release candidate, conda-forge and PyPI install commands, and a link to a 'What's New' page held elsewhere. No release notes reach the feed at all.

Read the full iris trajectory →

PySCF vs iris: editorial side-by-side

P
PySCF
ANALYTICS
2.5

Quantum chemistry package adding whole method families every release.

◆ Current state

PySCF is a Python-based quantum chemistry toolkit, and its release cadence is unusually feature-dense: each version lands multiple new electronic-structure methods rather than polishing existing ones. Recent releases have built out the GW/BSE excited-state stack, k-point RPA for periodic systems, higher-order coupled cluster, and multi-state PDFT with analytical gradients. Platform work runs alongside — Windows DLL compatibility, GPU4PySCF interfacing, and configurable einsum backends.

◆ Where it's heading

Two arcs are visible. The methods arc is pushing toward periodic (PBC) parity with molecular calculations — PBC GW, PBC RPA, SOC-ECP for PBC DFT, QM/MM for periodic systems all landed in this window. The infrastructure arc is about getting PySCF to run where it previously did not: Windows, GPUs, alternative tensor-contraction backends.

◆ Prediction

The PBC catch-up should continue, since each release closes another gap between molecular and periodic implementations of the same method; the entries do not indicate which gap is next.

I
iris
ANALYTICS
2.5

Iris ships steadily on a two-a-year cadence, but its feed publishes only pointers.

◆ Current state

Iris tags a release candidate roughly every four to five months — 3.13 through 3.16 over the past year — and the cadence is the only thing the feed actually reports. Every entry is the same seven-line template: a line saying this is a release candidate, conda-forge and PyPI install commands, and a link to a 'What's New' page held elsewhere. No release notes reach the feed at all.

◆ Where it's heading

The version numbers say a mature Met Office library is being maintained on a predictable schedule; nothing in the published entries says what is being maintained. Until the project puts release content in the tag body, its public trail will read as cadence without substance, and readers have to leave the feed to learn anything. The pattern has been identical across four consecutive releases, so it is a deliberate publishing choice rather than an oversight.

◆ Prediction

Expect v3.17.0rc0 around late 2026 on the same schedule, carrying the same boilerplate — the notes will again live on the documentation site rather than in the release entry.

Alternatives to PySCF and iris

Other Analytics products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either PySCF or iris.

See all PySCF alternatives → · See all iris alternatives →

Recent activity from PySCF and iris

Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.

  1. 13d agoirisv3.16.0rc0
  2. 24d agoPySCFBethe-Salpeter equation, k-point RPA, and Windows compatibility
  3. 2mo agoPySCFPatch release: missing CP2K basis data in wheels, ECP loading fallback
  4. 3mo agoPySCFASE band structure interface, SOC-ECP for periodic DFT, PCM surface discretization
  5. 4mo agoirisv3.15.0rc0
  6. 6mo agoPySCFNumPy 2.4 compatibility fix and smearing convergence tweak
  7. 6mo agoPySCFHigh-performance CCSDT/CCSDTQ, density-fitted NEVPT2, configurable einsum backend
  8. 9mo agoirisv3.14.0rc0
  9. 9mo agoPySCFMulti-state PDFT family lands with analytical gradients and QM/MM for periodic systems
  10. 1y agoirisv3.13.0rc0

Frequently asked questions

What is the difference between PySCF and iris?

They serve adjacent needs but don't currently overlap on shipped themes. PySCF and iris are shipping at a similar cadence (velocity 2.5 vs 2.5, both within Sparkpulse's "active" band). See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.

Is PySCF better than iris?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. PySCF and iris are shipping at a similar cadence (velocity 2.5 vs 2.5, both within Sparkpulse's "active" band). For your specific use case, the alternatives sections above list other Analytics products to evaluate alongside.

What are the best alternatives to PySCF?

Top PySCF alternatives in Analytics are ranked by recent ship velocity. Browse the "PySCF alternatives" section above for the current picks, or visit /alternatives/pyscf for the full list with editorial commentary on each.

What are the best alternatives to iris?

Top iris alternatives in Analytics are ranked by recent ship velocity. Browse the "iris alternatives" section above for the current picks, or visit /alternatives/scitools-iris for the full list with editorial commentary on each.