gasmodel

Estimation, forecasting, and simulation of generalized autoregressive score (GAS) models of Creal, Koopman, and Lucas (2013) doi:10.1002/jae.1279 and Harvey (2013) doi:10.1017/cbo9781139540933. Model specification allows for various conditional distributions, different parametrizations, exogenous variables, joint and separate modeling of exogenous variables and dynamics,higher score and autoregressive orders, custom and unconditional initial values of time-varying parameters, fixed and bounded values of coefficients, and missing values. Model estimation is performed by the maximum likelihood method and the Hessian matrix.