## [0.9.2] - 2026-03-05 - Gradient Fill, Matrix Inverse, Array Optimizations & Plot Fixes

[alaa-eddine]

[0.9.2] - 2026-03-05 - Gradient Fill, Matrix Inverse, Array Optimizations & Plot Fixes

Added

• Gradient Fill (fill()): Added support for Pine Script's gradient fill signature — fill(plot1, plot2, top_value, bottom_value, top_color, bottom_color). The FillHelper now detects the gradient form by checking whether the third argument is a number (gradient) or a string/color (simple fill), and stores per-bar top_value/bottom_value/top_color/bottom_color data for rendering.

Fixed

• matrix.inv() — Full NxN Support: Rewrote matrix.inv() from a 2×2-only implementation to a general Gauss-Jordan elimination with partial pivoting, supporting any square matrix of arbitrary size. Singular matrices (pivot < 1e-14) correctly return a NaN matrix.
• matrix.pinv() — Real Pseudoinverse: Rewrote matrix.pinv() from a placeholder stub to a correct Moore-Penrose pseudoinverse: square matrices use inv(), tall matrices (m > n) use (AᵀA)⁻¹Aᵀ, and wide matrices (m < n) use Aᵀ(AAᵀ)⁻¹.
• array.min() / array.max() Performance: Added an O(N) fast path for the common nth=0 case (find absolute min/max) instead of always sorting the full array O(N log N). Sorting is still used only when nth > 0.
• array.median() Performance: Replaced the for...of copy + complex sort comparator with a direct index loop and simple numeric sort for faster execution.
• array.percentile_linear_interpolation() Performance: Validate and copy the array in a single pass (eliminating the separate validValues allocation), then sort once.
• array.percentile_nearest_rank() Performance: Same single-pass validate-and-copy optimization as percentile_linear_interpolation.
• isPlot() with Undefined Title: Fixed the isPlot() helper check to accept plots that have no title property but do have a _plotKey property (e.g., plots created via fill() or accessed by callsite ID). Previously these were not recognised as plot objects, causing fill() to misidentify its arguments (contribution by @dcaoyuan, #142).