IRIS Toolbox Reference Manual

## !log_variables

List of log-linearised variables

#### Syntax

    !log_variables
        Variable_Name, Variable_Name,
        Variable_Name, ...

#### Syntax with inverted list

    !log_variables
        !all_but
        Variable_Name, Variable_Name,
        Variable_Name, ...

#### Syntax with regular expression(s)

    !log_variables
        Variable_Name, Variable_Name,
        Variable_Name, ...
        <REGEXP>, <REGEXP>, ...

#### Description

List all log-variables under this headings. Only measurement or transition variables can be declared as log-variables.

In non-linear models, all variables are linearised around the steady state or a balanced-growth path. If you wish to log-linearise some of them instead, put them on a `!log_variables` list. You can also use the `!all_but` keyword to indicate an inverse list: all variables will be log-linearised except those listed.

To create the list of log-variables, you can also use regular expressions, each enlosed in a pair of angle brackets, `<` and `>`. All measurement and transition variables whose names match one of the regular expressions will be declared as log-variables. See also help on regular expressions in the Matlab documentation.

#### Example

The following block of code will cause the variables `Y`, `C`, `I`, and `K` to be declared as log-variables, and hence log-linearised in the model solution, while `r` and `pie` will be linearised:

    !transition_variables
        Y, C, I, K, r, pie

    !log_variables
        Y, C, I, K

You can do the same job by writing

    !transition_variables
        Y, C, I, K, r, pie

    !log_variables
        !all_but
        r, pie

#### Example

We again achieve the same result as above, but now using a regular expression.

    !transition_variables
        Y, C, I, K, r, pie

    !log_variables
        <[A-Z]\w*>

The regular expression `[A-Z]\w*` selects all variables whose names start with an upper-case letter. Hence, again the variables `Y`, `C`, `I`, and `K` will be declared as log-variables.

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