— forbid leads and lags
— forbid expectation operators
This is implemented by moving the occbin_constraints expression to a separate
DataTree. As a side-effect, this removes the spurious non-linearity warning in
a stochastic context (because we were introducing inequalities and abs()
operators in the main DynamicModel tree).
The implementation of PacExpectationNode::toStatic() did not make sense. It
should normally never be called, hence we error out at this point.
Also do a cosmetic change in the PacExpectationNode::clone() methode.
Previously the first value was silently ignored. It’s better to explicitly
forbid this. If this change creates problems (since it’s a change in an
undocumented behaviour), we can turn it into a warning.
In particular, this implies that steady state values of endogenous in the
“occbin_constraints” block must now be specified using the STEADY_STATE()
operator (and not with a “_ss” suffix).
Moreover:
– make various simplifications to the fields generated under M_
– in the driver file, replace the call to occbin.initialize() by a few explicit operations
Ref. #68
Consequently drop “occbin” option to “model”.
Incidentally, allow more values in equation tag names (previously some keywords
such as “alpha” were disallowed).
Ref. #68
This option tells the preprocessor not to use the commutativity of addition and
multiplication when looking for common subexpressions.
As a consequence, when using this option, equations in various outputs (LaTeX,
JSON…) will appear as the user entered them.
There is however a potential performance cost to using this option, yet to be
determined.
Ref. dynare#1788
As the name implies, this option allows contemporaneous variables on the RHS.
The A0 matrix for contemporaneous variables is added as a second (optional)
output to the generated var_ar.m file. Note that for reduced-form VAR, this
matrix will be the identity.
Also, the user is now allowed to write the VAR models in a more flexible form:
the LHS must still be a single variable, but the RHS can be an arbitrary
expression (as long as it is linear, obviously). Internally, the preprocessor
now uses derivation to compute the coefficients of the AR and A0. This change
applies to both reduced-form and structural VAR models.
Ref. dynare#1785
Sébastien Villemot
Johannes Pfeifer
Stéphane Adjemian (Charybdis)