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Comparison · Analytics
regfusionr vs tulpa
A side-by-side editorial comparison of regfusionr and tulpa — release velocity, themes, recent moves, and the top alternatives to consider.
regfusionr vs tulpa: at a glance
What is regfusionr?
Registration fusion mapping goes bidirectional, and a vertex-indexing bug that silently returned wrong coordinates is fixed
regfusionr maps coordinates between volumetric brain templates (MNI152, Colin27) and the fsaverage surface. After four dormant years it returned in July 2026 with a release that fixes a coordinate-indexing bug, unblocks a previously disabled function, and completes the template-by-method matrix so all four combinations answer point queries. It also breaks compatibility by switching to the standard FREESURFER_HOME environment variable.
What is tulpa?
The 0.0.x train stops at CRAN: tulpa's engine ships to the ecosystem it already anchors.
tulpa is the C++/R Bayesian spatial inference engine sitting under gcol33's family of ecological occupancy packages, tagging 0.0.x releases several times a week. 0.1.0 is its first CRAN release, and the notes state outright that the engine surface is unchanged from 0.0.198 — the work is packaging discipline: local T bindings rebound to n_t/n_times, OpenMP teams capped under R CMD check, the pkgdown deploy narrowed, an aspell dictionary added. The window behind it splits between the S3 generics conversion and numerical-correctness work in the nested-Laplace grid.
regfusionr vs tulpa: editorial side-by-side
regfusionr
3.8ANALYTICS
Registration fusion mapping goes bidirectional, and a vertex-indexing bug that silently returned wrong coordinates is fixed
◆ Current state
regfusionr maps coordinates between volumetric brain templates (MNI152, Colin27) and the fsaverage surface. After four dormant years it returned in July 2026 with a release that fixes a coordinate-indexing bug, unblocks a previously disabled function, and completes the template-by-method matrix so all four combinations answer point queries. It also breaks compatibility by switching to the standard FREESURFER_HOME environment variable.
◆ Where it's heading
The package moved from a partial implementation to a complete one in a single release. Before this, vol_coords_to_fsaverage returned coordinates indexed by query position rather than by vertex index — results that looked plausible and were wrong — and fsaverage_to_vol was guarded behind a stop(). Both are now resolved, and the new Colin27 and MNI152 convenience functions make the mapping bidirectional. The sibling package haze shipped a maintenance release 56 minutes later, marking this as a coordinated sweep across the maintainer's neuroimaging stack.
◆ Prediction
With the four template-by-method combinations closed and the coordinate bug fixed, the next release is more likely to be CRAN-adjacent packaging or documentation than new mapping capability.
tulpa
7.5ANALYTICS
The 0.0.x train stops at CRAN: tulpa's engine ships to the ecosystem it already anchors.
◆ Current state
tulpa is the C++/R Bayesian spatial inference engine sitting under gcol33's family of ecological occupancy packages, tagging 0.0.x releases several times a week. 0.1.0 is its first CRAN release, and the notes state outright that the engine surface is unchanged from 0.0.198 — the work is packaging discipline: local T bindings rebound to n_t/n_times, OpenMP teams capped under R CMD check, the pkgdown deploy narrowed, an aspell dictionary added. The window behind it splits between the S3 generics conversion and numerical-correctness work in the nested-Laplace grid.
◆ Where it's heading
Two moves in nine days point at the same destination: the generics conversion made tulpa extensible by downstream packages, and CRAN admission makes it installable by them. The current cadence — several tags a week, some existing only to record a measurement that produced no code change — does not survive CRAN's submission overhead, so the release rhythm has to slow whether or not the project intends it. The correctness work still clusters on the joint nested-Laplace driver, and 0.1.0 extends the same diagnostics habit with .NL_AXIS_SD_REASONS, a closed vocabulary for an outer axis whose grid does not contain its own posterior mode.
◆ Prediction
Expect tulpaObs to follow tulpa onto CRAN, since it is the consumer whose registrations the engine has spent this window unblocking, and expect the version line to move in larger, less frequent steps now that each one carries a submission.
Alternatives to regfusionr and tulpa
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 regfusionr or tulpa.
Fulcrum
Fulcrum is betting its whole map stack on Esri, with a hard Google Maps cutoff on September 1.
Holistics
Holistics keeps fencing in the AI layer it spent the summer building.
Dovetail
Dovetail spent July opening doors to other tools and August making its own rooms easier to enter.
AgencyAnalytics
AgencyAI got skills three weeks ago; everything since has been making them routine.
NocoDB
Interfaces gets the permissions layer it needed, one release after launching.
See all regfusionr alternatives → · See all tulpa alternatives →
Recent activity from regfusionr and tulpa
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 18h agotulpaFirst CRAN release: engine surface unchanged from 0.0.198 ⚡
- 4d agotulpatulpa_re_aghq() exposes the mode/theta cross-Hessian
- 8d agotulpaDense batched joint path could silently drop a grid cell
- 8d agotulpaCalibration and goodness-of-fit entry points become S3 generics ⚡
- 9d agotulpaCUDA backend had two definitions; link order decided if it ran
- 9d agotulpaHyperparameter bounds now flag when they leave the node range
- 20d agoregfusionrVersion 0.3.0 -- vol_to_fsaverage, many convenience functions and fixes ⚡
- 4y agoregfusionrv0.2.0 -- surface to volume data projection
- 4y agoregfusionrv0.1.0: Initial release
Frequently asked questions
What is the difference between regfusionr and tulpa?
They serve adjacent needs but don't currently overlap on shipped themes. tulpa is currently shipping more aggressively (velocity 7.5 vs 3.8), with 2 editorial sparks in the last 30 days against 1. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is regfusionr better than tulpa?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. tulpa is currently shipping more aggressively (velocity 7.5 vs 3.8), with 2 editorial sparks in the last 30 days against 1. For your specific use case, the alternatives sections above list other Analytics products to evaluate alongside.
What are the best alternatives to regfusionr?
Top regfusionr alternatives in Analytics are ranked by recent ship velocity. Browse the "regfusionr alternatives" section above for the current picks, or visit /alternatives/regfusionr for the full list with editorial commentary on each.
What are the best alternatives to tulpa?
Top tulpa alternatives in Analytics are ranked by recent ship velocity. Browse the "tulpa alternatives" section above for the current picks, or visit /alternatives/tulpa for the full list with editorial commentary on each.