# udiag for Stata

Geometry and inference for U-shaped and inverted U-shaped relationships. The main command reports turning-point location, fitted response, curvature, and tolerance widths. Companion commands implement envelope, Fieller, asymmetry, shape, bootstrap, stability, cross-lag, ladder and consistency analyses.

```stata
net install udiag, from("https://udiag-stata.pages.dev") replace
discard
help udiag
```

The package requires Stata 16 or later. The underlying computation is retained from peakgeom 1.1.0. Version 1.1.1 introduces the udiag command and distribution name; peakgeom remains a compatibility entry point. Existing companion command names remain available. This distribution contains code and documentation, without research data or manuscript files.