IRIS Toolbox Reference Manual

get

Query model object properties

Syntax

Ans = get(M,Query)
[Ans,Ans,...] = get(M,Query,Query,...)

Input arguments

Output arguments

Valid queries to model objects

This is the categorised list of queries to model objects. Note that letter 'y' is used in various contexts to denote measurement variables or equations, 'x' transition variables or equations, 'e' shocks, 'p' parameters, 'g' exogenous variables, 'd' deterministic trend equations, and 'l' dynamic links. The property names are case insensitive.

Steady state
Variables, shocks, and parameters
Equations
First-order Taylor expansion of equations
Descriptions and aliases of variables, parameters, and shocks
Equation labels and aliases
Parameter values
Eigenvalues
Model structure, solution, build

Description

First-order Taylor expansion of equations

The expressions for symbolic/automatic derivatives of individual model equations returned by 'derivatives' are expressions that evaluate the derivatives with respect to all variables present in that equation at once. The list of variables with respect to which each equation is differentiated is returned by 'wrt'.

The expressions returned by the query 'derivatives' can refer to

Note that the lags and leads of variables must be, in general, preserved in the derivatives for non-stationary (unit-root) models. For stationary models, the lags and leads can be removed and each simply replaced with the current date of the respective variable.

Example

d = get(m,'derivatives');
w = get(m,'wrt');

The 1-by-N cell array d (where N is the total number of equations in the model) will contain expressions that evaluate to the vector of derivatives of the individual equations w.r.t. to the variables present in that equation:

d{k}

is an expression that returns, in general, a vector of M numbers. These M numbers are the derivatives of the k-th equation w.r.t to M variables whose list is in

w{k}