Function array_weights 

pub fn array_weights(
    exprs: &Array2<f64>,
    design: &Array2<f64>,
    var_design: Option<&Array2<f64>>,
    prior_n: f64,
    maxiter: usize,
    tol: f64,
) -> Array1<f64>

Estimate array quality weights by REML.

• exprs — ngenes x narrays expression matrix (no NA/infinite values).
• design — narrays x p design matrix (assumed full column rank).
• var_design — optional narrays x ngam variance design Z2 whose columns sum to zero; defaults to contr.sum(narrays).
• prior_n — prior support pulling weights toward 1 (limma default 10).
• maxiter, tol — Fisher-scoring controls (limma defaults 50, 1e-5).

Returns a length-narrays vector of array weights. Matches limma::arrayWeights(exprs, design) on data with no weights and no NAs.