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CMAQ vs mrbayes

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

CMAQ vs mrbayes: at a glance

FeatureCMAQmrbayes
SectorAnalyticsAnalytics
Velocity score0.00.0
Sparks · 30d00
Top themesair-quality, atmospheric-modeling, epa, scientific-computingmendelian-randomization, bayesian-inference, stan, jags
Last editorial update1h ago6h 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 mrbayes?

mrbayes spent 2026 auditing its own Bayesian MR estimators for coding errors.

mrbayes wraps Stan and JAGS implementations of Bayesian Mendelian randomization estimators — IVW, MR-Egger, radial Egger, and their multivariable forms. Most of the visible history is packaging work: dependency trimming, conditional examples so the package installs where JAGS will not compile, a maintainer handover. The 0.5.3 release in July 2026 breaks that pattern with a dense list of fixes inside the model code itself.

Read the full mrbayes trajectory →

CMAQ vs mrbayes: 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.

M
mrbayes
ANALYTICS
0.0

mrbayes spent 2026 auditing its own Bayesian MR estimators for coding errors.

◆ Current state

mrbayes wraps Stan and JAGS implementations of Bayesian Mendelian randomization estimators — IVW, MR-Egger, radial Egger, and their multivariable forms. Most of the visible history is packaging work: dependency trimming, conditional examples so the package installs where JAGS will not compile, a maintainer handover. The 0.5.3 release in July 2026 breaks that pattern with a dense list of fixes inside the model code itself.

◆ Where it's heading

The package has moved from packaging upkeep into a correctness-audit phase. 0.5.3 fixes a hardcoded three-exposure loop in MVMR-Egger reporting, a broken joint-prior branch, a sigma parameterization error in radial Egger, and several prior specifications — the profile of a maintainer reading their own model files closely rather than responding to bug reports. Platform work continues underneath: an R 4.3.0 floor inherited through a transitive dependency chain, and segfault fixes on macOS ARM.

◆ Prediction

Expect further audit-driven patches to the remaining rjags and Stan model files rather than new estimators; the fixes in 0.5.3 cluster in the Egger variants, which suggests that is where the reading is still in progress.

Alternatives to CMAQ and mrbayes

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 mrbayes.

See all CMAQ alternatives → · See all mrbayes alternatives →

Recent activity from CMAQ and mrbayes

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

  1. 1mo agomrbayesEstimator audit fixes MVMR-Egger loops and radial Egger sigma
  2. 1y agoCMAQCMAQ 5.5.0.3 enables parallel I/O, fixes DDM-3D control files
  3. 1y agoCMAQCMAQ 5.5.0.2 corrects ISAM aerosol and cloud processing
  4. 1y agoCMAQCMAQ 5.5.0.1 fixes SAPRC mechanism runs and NLCD mapping
  5. 1y agoCMAQCMAQ 5.5 adds global simulation coupled to MPAS-A
  6. 1y agoCMAQCMAQ 5.4.0.5: minor ELMO output fixes
  7. 1y agomrbayesMVMR rjags example gated on rjags being installed
  8. 1y agomrbayesExamples and tests skip when rstan or rjags is missing
  9. 1y agomrbayespkgdown site updated
  10. 1y agomrbayesHelper command added for installing JAGS
  11. 1y agomrbayesDependency surface trimmed; maintainer handover
  12. 2y agoCMAQCMAQ 5.4.0.4 fixes RBSTATS under ROS3, corrects a molecular weight

Frequently asked questions

What is the difference between CMAQ and mrbayes?

They serve adjacent needs but don't currently overlap on shipped themes. CMAQ and mrbayes are shipping at a similar cadence (velocity 0.0 vs 0.0, 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 CMAQ better than mrbayes?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. CMAQ and mrbayes are shipping at a similar cadence (velocity 0.0 vs 0.0, 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 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 mrbayes?

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