d2lv(u, B, h, model)"diagonal" for the diagonal model
and "extended" for the extended (full ARCH and GARCH parameter matrices) modelEngle, R.F. (2002), Dynamic Conditional Correlation: A Simple Class of Multivariate Generalized Autoregressive Conditional Heteroskedasticity Models. Journal of Business and Economic Statistics 20, 339--350.
Hafner, C.M. and H. Herwartz (2008), Analytical Quasi Maximum Likelihood Inference in Multivariate Volatility Models. Metrika 67, 219--239.