Changelog • tidysoilwater

tidysoilwater 1.2.0

fit_swrc_hcc() — joint simultaneous fitting of the Van Genuchten SWRC and Mualem-Van Genuchten K(h) function. Minimises a combined weighted residual (θ on linear scale, K on log₁₀ scale). Estimates θ_r, θ_s, α, n, Ks, and τ. Supports lower/upper bounds, fixed parameters, wrc_weight/hcc_weight scalars, grouping, and parallel fitting.
confint.fit_swrc() — profile-likelihood confidence intervals for parameters fitted by fit_swrc(). Uses the F-statistic profile approach (more reliable than normal-approximation intervals for nonlinear models). Returns a tidy tibble of (param, estimate, lower, upper, level) per group.

fit_swrc() — three new optional arguments:
- lower / upper — named vectors of box constraints; uses nls(algorithm = "port") internally (SEs from Jacobian, unchanged).
- fixed — named vector of parameters to hold at specified values; switches to stats::optim(method = "L-BFGS-B") with approximate SEs from the numerical Hessian.
- weights — bare column name or scalar for per-observation weights.
- Return type gains class fit_swrc (a tibble subclass) with metadata attributes enabling confint(). Fully backward-compatible.

soil_water_capacity() — analytical soil water capacity C(h) = −dθ/dh from the Van Genuchten (1980) model. Covers soilwater::cap().
saturation_index() — effective saturation S_e(h) = [1 + (α|h|)^n]^(−m). Dimensionless (0–1); equivalent to soilwater::swc(..., saturation_index = TRUE).
soil_water_diffusivity() — soil water diffusivity D(h) = K(h)/C(h). Covers soilwater::diffusivity().

hydraulic_conductivity() — new tau argument (tortuosity/connectivity parameter, default 0.5). Previously hardcoded at 0.5 (Mualem 1976); now exposed as a free parameter matching soilhypfit::hc_model(). Default tau = 0.5 is fully backward-compatible.

Initial release.

swrc_van_genuchten() — Van Genuchten (1980) soil water retention curve. Returns volumetric water content θ(h) for any combination of scalar parameters and tidy data columns. Handles 1 M rows in < 20 ms.
hydraulic_conductivity() — Mualem-Van Genuchten unsaturated hydraulic conductivity K(h). Handles 1 M rows in < 40 ms.
fit_swrc() — fits Van Genuchten parameters to observed (h, θ) data via nonlinear least squares. Supports grouped tibbles (one fit per group) and optional parallel fitting via parallel::mclapply() on Unix systems.

All functions accept bare column names (tidy evaluation) or scalar numeric values interchangeably.
fit_swrc() with workers > 1 delivers near-linear parallel speedup on Unix; silently falls back to sequential on Windows.
broom::tidy() output is used internally so fitted parameters, standard errors, and convergence status are all returned in a single tidy tibble.