statsmodels.tsa.statespace.tools.constrain_stationary_univariate

statsmodels.tsa.statespace.tools.constrain_stationary_univariate(unconstrained)[source]

Transform unconstrained parameters used by the optimizer to constrained parameters used in likelihood evaluation

Parameters

unconstrained (array) – Unconstrained parameters used by the optimizer, to be transformed to stationary coefficients of, e.g., an autoregressive or moving average component.

Returns

constrained – Constrained parameters of, e.g., an autoregressive or moving average component, to be transformed to arbitrary parameters used by the optimizer.

Return type

array

References

*

Monahan, John F. 1984. “A Note on Enforcing Stationarity in Autoregressive-moving Average Models.” Biometrika 71 (2) (August 1): 403-404.