Stan Development

Use this skill when working with Stan models for Bayesian inference and probabilistic programming, particularly when integrating with R (cmdstanr) or Python (cmdstanpy).

Modern Stan Syntax

Array Declarations (IMPORTANT)

Use new array syntax introduced in Stan 2.26+:

// Good - Modern syntax (Stan 2.26+)
array[10] int x;              // Array of 10 integers
array[N] real y;              // Array of N reals
array[N, M] real z;           // 2D array
array[N] vector[K] v;         // Array of vectors

// Avoid - Old syntax (deprecated)
int x[10];                    // Old style