Transform a real-valued parameter to the interval (-1, 1)

Applies the scaled logistic transformation \(2 / (1 + e^{-2x}) - 1\) to map an unconstrained real value to \((-1, 1)\), suitable for parameterising correlation coefficients. Used in SPoRC to back-transform raw correlation parameters before constructing AR(1) and constant covariance matrices for logistic-normal composition likelihoods.

Usage

rho_trans(x)

Arguments

x

Numeric. Unconstrained real-valued parameter.

Value

Numeric. Transformed value in \((-1, 1)\).

See also

Other Utility: fit_model(), get_logistN_Sigma(), get_par_est_info(), post_optim_sanity_checks(), set_data_indicator_unused()