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CMAQ vs distributions3

A side-by-side editorial comparison of CMAQ and distributions3 — release velocity, themes, recent moves, and the top alternatives to consider.

CMAQ vs distributions3: at a glance

FeatureCMAQdistributions3
SectorAnalyticsAnalytics
Velocity score0.02.5
Sparks · 30d00
Top themesair-quality, atmospheric-modeling, epa, scientific-computingr-package, probability-distributions, statistical-modelling, maintainership
Last editorial update42m ago4h ago
WebsiteVisit →Visit →

What is CMAQ?

CMAQ went global in v5.5, and has been patching that surface ever since.

CMAQ is the EPA's Community Multiscale Air Quality modeling system, used for regulatory and research air quality simulation. Its release rhythm is strictly two-tier: numbered major versions carry new science and fresh benchmark datasets, while the x.y.z.n updates carry bug fixes against documentation and benchmarks that stay pinned to the parent version. The current line is v5.5, which introduced CRACMM2 chemistry and coupling to MPAS-A meteorology, followed by three patch rollups.

Read the full CMAQ trajectory →

What is distributions3?

distributions3 changes hands to Achim Zeileis, and a moment calculation bug goes with it.

An R package giving probability distributions a consistent object interface — d/p/q/r functions, moments, and prodist() methods that extract a fitted distribution from a regression object. Releases are infrequent, roughly one a year, and the last one is largely administrative: Achim Zeileis takes over maintenance from Alex Hayes, with all URLs and documentation updated to match, alongside a fix to incorrect moment calculations reported by a user.

Read the full distributions3 trajectory →

CMAQ vs distributions3: editorial side-by-side

C
CMAQ
ANALYTICS
0.0

CMAQ went global in v5.5, and has been patching that surface ever since.

◆ Current state

CMAQ is the EPA's Community Multiscale Air Quality modeling system, used for regulatory and research air quality simulation. Its release rhythm is strictly two-tier: numbered major versions carry new science and fresh benchmark datasets, while the x.y.z.n updates carry bug fixes against documentation and benchmarks that stay pinned to the parent version. The current line is v5.5, which introduced CRACMM2 chemistry and coupling to MPAS-A meteorology, followed by three patch rollups.

◆ Where it's heading

The v5.5 patches cluster around the newest and most sensitive components. ISAM source apportionment and DDM-3D sensitivity analysis account for corrections in every one of the three updates, and CRACMM2 needed fixes within months of release. That is the expected shape after a major version lands: the science is stable, the instrumentation built on top of it is not. Parallel I/O work in the latest patch suggests the global configurations are now being run at scales that expose throughput limits.

◆ Prediction

The next major version will fold these fixes in with new science, documentation and benchmark data — the release notes state this explicitly each time. Until then, expect further ISAM and DDM-3D corrections, which have appeared in every patch so far.

D2.5

distributions3 changes hands to Achim Zeileis, and a moment calculation bug goes with it.

◆ Current state

An R package giving probability distributions a consistent object interface — d/p/q/r functions, moments, and prodist() methods that extract a fitted distribution from a regression object. Releases are infrequent, roughly one a year, and the last one is largely administrative: Achim Zeileis takes over maintenance from Alex Hayes, with all URLs and documentation updated to match, alongside a fix to incorrect moment calculations reported by a user.

◆ Where it's heading

The package's growth has come in two modes. Early releases absorbed whole families of distributions from outside contributors — the extreme-value set, Erlang, later the Poisson binomial — while later ones tightened the interface itself with is_discrete() and is_continuous() generics and elementwise type-safety when applying a distribution vector to a numeric vector. The handover is the notable event in the current window: maintenance moves to the author of the surrounding statistical ecosystem this package already integrates with through prodist() and countreg, which suggests the interface work will continue over the distribution-collection work.

◆ Prediction

Expect closer alignment with Zeileis's own packages, with prodist() coverage widening to more model classes; the entries here do not indicate whether new distribution families remain on the agenda.

Alternatives to CMAQ and distributions3

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 CMAQ or distributions3.

See all CMAQ alternatives → · See all distributions3 alternatives →

Recent activity from CMAQ and distributions3

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

  1. 24d agodistributions3Maintenance moves to Achim Zeileis; moment calculations corrected
  2. 10mo agodistributions3ggplot2 compatibility for the plotting functions
  3. 1y agoCMAQCMAQ 5.5.0.3 enables parallel I/O, fixes DDM-3D control files
  4. 1y agoCMAQCMAQ 5.5.0.2 corrects ISAM aerosol and cloud processing
  5. 1y agoCMAQCMAQ 5.5.0.1 fixes SAPRC mechanism runs and NLCD mapping
  6. 1y agoCMAQCMAQ 5.5 adds global simulation coupled to MPAS-A
  7. 1y agodistributions3Poisson binomial distribution, with a normal-approximation fallback
  8. 1y agoCMAQCMAQ 5.4.0.5: minor ELMO output fixes
  9. 2y agoCMAQCMAQ 5.4.0.4 fixes RBSTATS under ROS3, corrects a molecular weight
  10. 3y agodistributions3is_discrete and is_continuous generics, plus elementwise type-safety
  11. 4y agodistributions3Extreme-value family, Erlang, and a plotting generic

Frequently asked questions

What is the difference between CMAQ and distributions3?

They serve adjacent needs but don't currently overlap on shipped themes. distributions3 is currently shipping more aggressively (velocity 2.5 vs 0.0), with 0 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.

Is CMAQ better than distributions3?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. distributions3 is currently shipping more aggressively (velocity 2.5 vs 0.0), with 0 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Analytics products to evaluate alongside.

What are the best alternatives to CMAQ?

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

What are the best alternatives to distributions3?

Top distributions3 alternatives in Analytics are ranked by recent ship velocity. Browse the "distributions3 alternatives" section above for the current picks, or visit /alternatives/distributions3-r for the full list with editorial commentary on each.