Asymmetric Smoothed-Association Matrices via GAM Fits R package janusplot version 0.1.0 Render a pairwise, asymmetric smoothed-association matrix of continuous variables. Each cell shows the fitted spline from an 'mgcv' generalised additive model, with the upper triangle displaying 'gam(x_j ~ s(x_i))' and the lower triangle 'gam(x_i ~ s(x_j))'. Unlike Pearson's correlation matrix, the visualisation is intentionally asymmetric, revealing heteroscedasticity, leverage, and directional non-linearity that a single scalar correlation hides. An asymmetry index and a 24-category shape taxonomy quantify the directional difference and qualitative form of each fitted smooth. Software Depends: R (>= 4.3.0) Imports: mgcv (>= 1.9.0), ggplot2 (>= 3.5.0), patchwork (>= 1.1.0), grid, stats, cli (>= 3.6.0), lifecycle, rlang (>= 1.1.0) Suggests: agridat, future, future.apply, knitr, MASS, palmerpenguins, rmarkdown, testthat (>= 3.0.0), vdiffr (>= 1.0.0), withr Max Moldovan <max.moldovan@adelaide.edu.au> Comprehensive R Archive Network (CRAN) Max Moldovan [aut, cre, cph] (ORCID: <https://orcid.org/0000-0001-9680-8474>) GPL (>= 3) 2026-04-28 application/tgz https://CRAN.R-project.org/package=janusplot doi:10.32614/CRAN.package.janusplot en-AU