PurpleAir
The R client for PurpleAir sensors keeps finding its time-averaging was wrong.
Comparison · Analytics
lstar vs slope
A side-by-side editorial comparison of lstar and slope — release velocity, themes, recent moves, and the top alternatives to consider.
lstar vs slope: at a glance
What is lstar?
A single-cell data store commits to Zarr v3 and range-readable hosting across four language surfaces
lstar stores single-cell data behind one C++ core with Python, R and JS/WASM bindings, and ships a browser viewer that reads the store directly. Zarr v3 is now the default on-disk format across all four surfaces, with zstd compression and sharding that packs many chunks into fewer objects. Viewer stores are compressed per field and resolved at chunk granularity, so a hosted viewer fetches only what it displays. The tag stream carries both lstar and lstar-sc releases.
What is slope?
A year after gutting itself for a C++ rewrite, SLOPE is back to polishing the interface
SLOPE fits sorted L-one penalized regression models. In July 2025 it replaced its entire solver with the external libslope C++ library, removing the ADMM solver, dropping debugging fields, changing alpha scaling and warning users directly that the breakage was extensive. The releases since have rebuilt convenience on top of that core: summary() and refit() methods for cross-validated objects, automatic refitting in cvSLOPE(), and a threading default reduced from half the available cores to one.
lstar vs slope: editorial side-by-side
lstar
5.0ANALYTICS
A single-cell data store commits to Zarr v3 and range-readable hosting across four language surfaces
◆ Current state
lstar stores single-cell data behind one C++ core with Python, R and JS/WASM bindings, and ships a browser viewer that reads the store directly. Zarr v3 is now the default on-disk format across all four surfaces, with zstd compression and sharding that packs many chunks into fewer objects. Viewer stores are compressed per field and resolved at chunk granularity, so a hosted viewer fetches only what it displays. The tag stream carries both lstar and lstar-sc releases.
◆ Where it's heading
The through-line is making a hosted store cheap to read. Sharding addresses the file-per-chunk explosion that makes many-chunk arrays awkward to host; per-field compression with chunk-granular resolution means colouring an embedding by one gene fetches one column rather than an array. The 0.2.x patches are the cost of maintaining four surfaces at once — a WASM heap crash that only browsers exercise, and a count-basis orientation defect where all three surfaces normalized in memory and none owned the on-disk layout.
◆ Prediction
The orientation bug's root cause — no surface owning the on-disk representation while all three normalized in memory — is the kind of gap that usually produces a validation or ownership change rather than another point fix.
slope
0.0ANALYTICS
A year after gutting itself for a C++ rewrite, SLOPE is back to polishing the interface
◆ Current state
SLOPE fits sorted L-one penalized regression models. In July 2025 it replaced its entire solver with the external libslope C++ library, removing the ADMM solver, dropping debugging fields, changing alpha scaling and warning users directly that the breakage was extensive. The releases since have rebuilt convenience on top of that core: summary() and refit() methods for cross-validated objects, automatic refitting in cvSLOPE(), and a threading default reduced from half the available cores to one.
◆ Where it's heading
The arc runs rewrite, then repair, then convenience. The 1.2.0 release is the repair phase — coefficients_scaled was returning unscaled values, which silently affected every coef.SLOPE() call — and 2.0.0 onward is convenience, with refit() now working without re-supplying training data. The tag timestamps are non-monotonic: 1.0.1 is stamped a minute after 1.1.0 despite the lower version, so ordering here reflects when tags were pushed, not what superseded what.
◆ Prediction
With the cross-validation workflow now closing itself out through automatic refitting, further work is more likely to extend the summary and plotting surface than to touch the solver again.
Alternatives to lstar and slope
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 lstar or slope.
piecepackr
A board game graphics package runs one of the most disciplined deprecation cycles in R.
e2tree
The explainable-ensemble-tree package now measures whether its own explanations are faithful.
discretefdr
The discrete-data FDR package is being pared into one piece of a larger multiple-testing suite.
contentanalysis
A scientific-text analysis package moved from counting citations to classifying argument structure.
relialearnr
The teaching arm of an R reliability suite keeps pace with whatever its analysis siblings ship.
Recent activity from lstar and slope
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 21d agolstarViewer count-basis orientation fixed; existing stores need re-prep
- 26d agolstarWASM viewer crash on resizable heaps fixed
- 1mo agolstarlstar 0.2.0 ⚡
- 1mo agolstarMeasure state inferred from content, not slot name
- 2mo agosloperefit() defaults to training data; class-mismatch scoring fixed
- 6mo agoslopeCross-validation now refits automatically and gains summary methods
- 9mo agoslopeSingle-threaded by default, interruptible, and a scaling bug fixed
- 9mo agoslopeM1 Mac test fix
- 9mo agoslopeGlioma gene expression dataset added
- 1y agoslopeSLOPE 1.0.0 ⚡
Frequently asked questions
What is the difference between lstar and slope?
They serve adjacent needs but don't currently overlap on shipped themes. lstar is currently shipping more aggressively (velocity 5.0 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 lstar better than slope?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. lstar is currently shipping more aggressively (velocity 5.0 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 lstar?
Top lstar alternatives in Analytics are ranked by recent ship velocity. Browse the "lstar alternatives" section above for the current picks, or visit /alternatives/lstar for the full list with editorial commentary on each.
What are the best alternatives to slope?
Top slope alternatives in Analytics are ranked by recent ship velocity. Browse the "slope alternatives" section above for the current picks, or visit /alternatives/slope for the full list with editorial commentary on each.