datefixR
The messy-date parser rewrote its core in Rust and came out 300x faster.
Comparison · Analytics
fellingdater vs simulist
A side-by-side editorial comparison of fellingdater and simulist — release velocity, themes, recent moves, and the top alternatives to consider.
fellingdater vs simulist: at a glance
What is fellingdater?
Went from estimating felling dates to doing the crossdating that produces them.
fellingdater estimates when a tree was felled from sapwood measurements, the core inference in dendrochronological dating of timber. Version 1.0.0 passed rOpenSci review with that scope, and the 2024 releases were mostly about the accompanying JOSS paper and user-supplied sapwood datasets. Version 1.2.0 changed the package's remit substantially, adding an entire trs_* family for tree-ring series handling: crossdating with multiple statistical measures, the Hollstein and Baillie-Pilcher t-value transformations, parallel variation percentages, synthetic series generation, and dated-series plotting.
What is simulist?
simulist stopped simulating clean outbreaks and started simulating the mess real surveillance data arrives in.
simulist generates synthetic line list and contact-tracing data for outbreak analytics as part of the Epiverse-TRACE stack. It reached stable status in 0.6.0 and was published in JOSS alongside 0.7.0 in February 2026. Its distinguishing feature is no longer the epidemic simulation itself but the post-processing layer that degrades the output into realistic data.
fellingdater vs simulist: editorial side-by-side
fellingdater
0.0ANALYTICS
Went from estimating felling dates to doing the crossdating that produces them.
◆ Current state
fellingdater estimates when a tree was felled from sapwood measurements, the core inference in dendrochronological dating of timber. Version 1.0.0 passed rOpenSci review with that scope, and the 2024 releases were mostly about the accompanying JOSS paper and user-supplied sapwood datasets. Version 1.2.0 changed the package's remit substantially, adding an entire trs_* family for tree-ring series handling: crossdating with multiple statistical measures, the Hollstein and Baillie-Pilcher t-value transformations, parallel variation percentages, synthetic series generation, and dated-series plotting.
◆ Where it's heading
The package has expanded backwards along the workflow. It began at the last step — given dated series, estimate the felling date — and 1.2.0 added the step before it, establishing those dates by crossdating in the first place. Version 1.2.1 is early polish on that new surface: axis control, non-syntactic column names, encoding safety in read_fh(). The direction is a single package covering the chain from raw ring widths to a felling-date estimate.
◆ Prediction
Expect the trs_* family to keep accumulating polish and additional crossdating statistics, since it is barely a year old and 1.2.1 was already fixing its plotting and top_n behaviour. Whether the two halves of the package get unified into one workflow interface is the open question the entries do not answer.
simulist
0.0ANALYTICS
simulist stopped simulating clean outbreaks and started simulating the mess real surveillance data arrives in.
◆ Current state
simulist generates synthetic line list and contact-tracing data for outbreak analytics as part of the Epiverse-TRACE stack. It reached stable status in 0.6.0 and was published in JOSS alongside 0.7.0 in February 2026. Its distinguishing feature is no longer the epidemic simulation itself but the post-processing layer that degrades the output into realistic data.
◆ Where it's heading
The scope moved outward in two steps. 0.5.0 added truncate_linelist() and messy_linelist() to produce right-truncated snapshots and data with missingness and inconsistencies; 0.6.0 added censor_linelist() for grouping dates into intervals with a weekend-reporting effect. The simulation core has meanwhile settled — 0.7.0's changes are interface polish: weighted sex sampling and <epiparameter> objects accepted for reporting_delay.
◆ Prediction
Post-processing is where the recent work is, so further realism controls — additional reporting artefacts or interval schemes — are a likelier next step than new epidemic model structures.
Alternatives to fellingdater and simulist
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 fellingdater or simulist.
maplegend
The legend engine mapsf spun out, now covering legend types the parent map package can draw.
lang
R help pages translated on demand by whichever LLM you point it at.
mapsf
Thematic mapping in base R that finally got a theming system, then spent two years polishing legends.
qualtRics
qualtRics moved its contact functions onto XM Directory days before the old endpoints died.
fabletools
The tidyverts forecasting core rebuilt model combination on full residual covariance.
See all fellingdater alternatives → · See all simulist alternatives →
Recent activity from fellingdater and simulist
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 4mo agofellingdaterPolish for the crossdating plots and file reader
- 6mo agosimulistJOSS paper corrections
- 6mo agosimulistWeighted sex sampling and epiparameter objects for reporting delays
- 11mo agosimulistcensor_linelist() adds interval censoring and a weekend effect
- 1y agofellingdaterAdds a full crossdating and tree-ring analysis toolkit ⚡
- 1y agofellingdaterUser-supplied sapwood data works across all functions
- 1y agofellingdaterFixes fd_report() with user-defined sapwood files
- 1y agosimulistPost-processing arrives: truncated snapshots and deliberately messy line lists ⚡
- 1y agosimulistEvery sim_*() argument gains a default
- 2y agosimulistInfectious period replaces contact interval; time-varying fatality risk added
- 2y agofellingdaterJOSS paper accepted; citation updated
- 2y agofellingdaterAdds a workflow vignette ahead of JOSS submission
Frequently asked questions
What is the difference between fellingdater and simulist?
They serve adjacent needs but don't currently overlap on shipped themes. fellingdater and simulist 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 fellingdater better than simulist?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. fellingdater and simulist 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 fellingdater?
Top fellingdater alternatives in Analytics are ranked by recent ship velocity. Browse the "fellingdater alternatives" section above for the current picks, or visit /alternatives/fellingdater for the full list with editorial commentary on each.
What are the best alternatives to simulist?
Top simulist alternatives in Analytics are ranked by recent ship velocity. Browse the "simulist alternatives" section above for the current picks, or visit /alternatives/simulist for the full list with editorial commentary on each.