This options relates to alternative numerical hessian computations:
optim=('Hessian',1) is the default dynare numeric Hessian
optim=('Hessian',0) is the outer product gradient
optim=('Hessian',2) is the 'mixed' outer product gradient, where diagonal elements using second order derivation formula,
Both 0 and 2 cases require univariate filters, to ensure using maximum number of individual densities.
Marco Ratto
Stéphane Adjemian (Charybdis)