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Comparison · Infra & APIs
rwasm vs SLmetrics
A side-by-side editorial comparison of rwasm and SLmetrics — release velocity, themes, recent moves, and the top alternatives to consider.
Shared themes:r-package
rwasm vs SLmetrics: at a glance
What is rwasm?
The toolchain that gets R packages into the browser is optimising for payload size, not features.
rwasm cross-compiles R packages to WebAssembly and assembles the virtual filesystem images that webR loads. Its three releases have moved from making cross-compilation work at all — Autoconf overrides, uname and pkg-config shims, OpenMP support — to controlling how the resulting artefacts are packaged and shipped. Every release is pinned to a specific webR version floor.
What is SLmetrics?
A young ML metrics package rewrote its own backend twice in six months chasing speed.
SLmetrics provides supervised learning evaluation metrics for R — confusion matrices, classification and regression measures, ROC and precision-recall curves — with the computation pushed into C++. After a series of pre-releases it now runs on an Armadillo backend, supports OpenMP parallelism and LAPACK/BLAS, and reports 5-20x speedups over its earlier implementations. The API has been reshaped for extensibility, with an estimator argument replacing the fixed aggregation options.
rwasm vs SLmetrics: editorial side-by-side
rwasm
0.0INFRA · APIS
The toolchain that gets R packages into the browser is optimising for payload size, not features.
◆ Current state
rwasm cross-compiles R packages to WebAssembly and assembles the virtual filesystem images that webR loads. Its three releases have moved from making cross-compilation work at all — Autoconf overrides, uname and pkg-config shims, OpenMP support — to controlling how the resulting artefacts are packaged and shipped. Every release is pinned to a specific webR version floor.
◆ Where it's heading
The arc runs from correctness to delivery. The first release fought the cross-compilation environment itself, isolating builds from host libraries and shimming the tools configure scripts expect. The second replaced Emscripten's own file_packager with a custom metadata path and added gzip compression for filesystem images. The third is pure coordination, rebuilding the build system for webR 0.5.0. That cadence — roughly annual, each release gated on a webR version — makes this a component of the webR release train rather than an independently moving project.
◆ Prediction
The next release will most likely follow the next webR version, since two of three releases so far have been driven by a webR floor rather than by rwasm's own agenda.
SLmetrics
0.0INFRA · APIS
A young ML metrics package rewrote its own backend twice in six months chasing speed.
◆ Current state
SLmetrics provides supervised learning evaluation metrics for R — confusion matrices, classification and regression measures, ROC and precision-recall curves — with the computation pushed into C++. After a series of pre-releases it now runs on an Armadillo backend, supports OpenMP parallelism and LAPACK/BLAS, and reports 5-20x speedups over its earlier implementations. The API has been reshaped for extensibility, with an estimator argument replacing the fixed aggregation options.
◆ Where it's heading
Every release in this timeline is about making the same metrics compute faster or compose better. The backend moved from Rcpp to plain C++, gained OpenMP, then was ported wholesale from Eigen to Armadillo with heavy templating. In parallel the author has been widening the API's joints: generic S3 signatures, an extensible estimator argument, and function signatures loose enough that wrapping packages can rename arguments. Bundled datasets and embedded formulas in the docs point at teaching and benchmarking use. The package still labels itself pre-release, which is consistent with how freely it has broken argument names along the way.
◆ Prediction
A stable non-pre-release version is the natural next step now that the backend has settled on Armadillo, though the repeated willingness to rename arguments suggests more API churn may come first.
Alternatives to rwasm and SLmetrics
Other Infra & APIs 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 rwasm or SLmetrics.
rJavaEnv
The R package that installs Java for you stopped needing an update every time Java ships.
traits.build
The AusTraits engine, generalised for anyone's trait database, now links measurements to real specimens.
Fail2Ban
Fail2Ban finally ships 1.1.1 after 14 months in beta, with a botched deb package on the way out the door
plogr
A logging header for Rcpp packages that sat untouched for nine years, then changed how it switches on
dockViewR
Draggable dock panels for Shiny, learning that layout state belongs on the client
See all rwasm alternatives → · See all SLmetrics alternatives →
Recent activity from rwasm and SLmetrics
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 1y agorwasmBuild system realigned for webR 0.5.0
- 1y agoSLmetricsArmadillo backend brings 5-20x speedups and an extensible metrics API ⚡
- 1y agoSLmetricsConsistent S3 signatures and three bundled datasets
- 1y agoSLmetricsRegression metrics 2-10x faster with reworked OpenMP controls
- 1y agoSLmetricsOpenMP parallelism and a soft-label entropy family
- 1y agoSLmetricsCross-entropy loss and relative RMSE with three normalisations
- 1y agoSLmetricsSample weights flow through the confusion matrix
- 1y agorwasmrwasm 0.2.0 ⚡
- 2y agorwasmCross-compilation gains OpenMP, Autoconf overrides and host isolation
Frequently asked questions
What is the difference between rwasm and SLmetrics?
Both compete on the same themes — r-package — within Infra & APIs. rwasm and SLmetrics 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 rwasm better than SLmetrics?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. rwasm and SLmetrics 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 Infra & APIs products to evaluate alongside.
What are the best alternatives to rwasm?
Top rwasm alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "rwasm alternatives" section above for the current picks, or visit /alternatives/rwasm for the full list with editorial commentary on each.
What are the best alternatives to SLmetrics?
Top SLmetrics alternatives in Infra & APIs are ranked by recent ship velocity. Browse the "SLmetrics alternatives" section above for the current picks, or visit /alternatives/slmetrics for the full list with editorial commentary on each.