earthUI 0.1.0

Core

• Shiny GUI for interactive earth (MARS) model building.
• Data import from CSV and Excel files with automatic snake_case column naming.
• Variable configuration with include, factor, and linear-only controls.
• Full exposure of all earth() parameters through the GUI with inline help popovers.
• Cross-validation automatically enabled for interaction and variance models.
• Settings persistence via localStorage across browser sessions.
• Light/dark mode toggle.

Allowed Interactions

• Allowed interaction matrix for constraining degree >= 2 models.
• CSS sticky headers — top row and left column stay visible while scrolling.
• Click variable name to toggle all its interactions (symmetric toggle).
• Allow All / Clear All buttons.

Multivariate Models

• Multi-response model support: select multiple target variables to fit cbind() earth models.
• Per-response equation display, summary metrics, and ANOVA decomposition.
• All plot functions accept response_idx to select which response to visualize.
• Observation weights via the weights parameter in fit_earth().

Model Fitting

• Asynchronous background fitting via callr::r_bg() with real-time trace display and elapsed timer.
• Automatic nfold/ncross adjustment for variance models.
• Synchronous fallback when callr is unavailable.

Visualization

• Variable importance bar charts.
• Per-variable contribution plots with piecewise-linear slope labels and knot markers.
• g-function plots: 1D line, interactive 3D surface (plotly), static 3D perspective (persp()), and filled contour.
• Correlation matrix heatmap.
• Diagnostic plots: residuals vs fitted, Q-Q, actual vs predicted.
• Adaptive axis formatting — 3 decimal places for lat/long-scale data, commas for large values, dollar signs for target.
• Slope labels scaled to axis range (/0.001 for small-range, /unit for large-range variables).

Model Equation

• LaTeX equation with g-function notation rendered via MathJax in the app and native LaTeX in PDF reports.
• Full LaTeX special character escaping (_, $, %, &, #).

Report Export

• Publication-quality HTML, PDF, and Word reports via Quarto.
• Both 3D perspective and contour plots for degree-2 groups in static reports.
• Earth model summary, ANOVA decomposition, and raw earth output sections.