3. Running Dynare

In order to give instructions to Dynare, the user has to write a model file whose filename extension must be .mod or .dyn. This file contains the description of the model and the computing tasks required by the user. Its contents are described in The model file.

3.1. Dynare invocation

Once the model file is written, Dynare is invoked using the dynare command at the MATLAB or Octave prompt (with the filename of the .mod given as argument).

In practice, the handling of the model file is done in two steps: in the first one, the model and the processing instructions written by the user in a model file are interpreted and the proper MATLAB or GNU Octave instructions are generated; in the second step, the program actually runs the computations. Both steps are triggered automatically by the dynare command.

MATLAB/Octave command: dynare FILENAME[.mod] [OPTIONS…]

This command launches Dynare and executes the instructions included in FILENAME.mod. This user-supplied file contains the model and the processing instructions, as described in The model file. The options, listed below, can be passed on the command line, following the name of the .mod file or in the first line of the .mod file itself (see below).

dynare begins by launching the preprocessor on the .mod file. By default (unless use_dll option has been given to model), the preprocessor creates three intermediary files:

  • +FILENAME/driver.m

    Contains variable declarations, and computing tasks.

  • +FILENAME/dynamic.m

    Contains the dynamic model equations. Note that Dynare might introduce auxiliary equations and variables (see Auxiliary variables). Outputs are the residuals of the dynamic model equations in the order the equations were declared and the Jacobian of the dynamic model equations. For higher order approximations also the Hessian and the third-order derivatives are provided. When computing the Jacobian of the dynamic model, the order of the endogenous variables in the columns is stored in M_.lead_lag_incidence. The rows of this matrix represent time periods: the first row denotes a lagged (time t-1) variable, the second row a contemporaneous (time t) variable, and the third row a leaded (time t+1) variable. The columns of the matrix represent the endogenous variables in their order of declaration. A zero in the matrix means that this endogenous does not appear in the model in this time period. The value in the M_.lead_lag_incidence matrix corresponds to the column of that variable in the Jacobian of the dynamic model. Example: Let the second declared variable be c and the (3,2) entry of M_.lead_lag_incidence be 15. Then the 15th column of the Jacobian is the derivative with respect to c(+1).

  • +FILENAME/static.m

    Contains the long run static model equations. Note that Dynare might introduce auxiliary equations and variables (see Auxiliary variables). Outputs are the residuals of the static model equations in the order the equations were declared and the Jacobian of the static equations. Entry (i,j) of the Jacobian represents the derivative of the ith static model equation with respect to the jth model variable in declaration order.

These files may be looked at to understand errors reported at the simulation stage.

dynare will then run the computing tasks by executing +FILENAME/driver.m. If a user needs to rerun the computing tasks without calling the preprocessor (or without calling the dynare command), for instance because he has modified the script, he just have to type the following on the command line:

>> FILENAME.driver

A few words of warning are warranted here: under Octave the filename of the .mod file should be chosen in such a way that the generated .m files described above do not conflict with .m files provided by Octave or by Dynare. Not respecting this rule could cause crashes or unexpected behaviour. In particular, it means that the .mod file cannot be given the name of an Octave or Dynare command. For instance, under Octave, it also means that the .mod file cannot be named test.mod or example.mod.

Options

noclearall

By default, dynare will issue a clear all command to MATLAB (<R2015b) or Octave, thereby deleting all workspace variables and functions; this option instructs dynare not to clear the workspace. Note that starting with Matlab 2015b dynare only deletes the global variables and the functions using persistent variables, in order to benefit from the JIT (Just In Time) compilation. In this case the option instructs dynare not to clear the globals and functions.

onlyclearglobals

By default, dynare will issue a clear all command to MATLAB versions before 2015b and to Octave, thereby deleting all workspace variables; this option instructs dynare to clear only the global variables (i.e. M_, options_, oo_, estim_params_, bayestopt_, and dataset_), leaving the other variables in the workspace.

debug

Instructs the preprocessor to write some debugging information about the scanning and parsing of the .mod file.

notmpterms

Instructs the preprocessor to omit temporary terms in the static and dynamic files; this generally decreases performance, but is used for debugging purposes since it makes the static and dynamic files more readable.

savemacro[=FILENAME]

Instructs dynare to save the intermediary file which is obtained after macro-processing (see Macro-processing language); the saved output will go in the file specified, or if no file is specified in FILENAME-macroexp.mod

onlymacro

Instructs the preprocessor to only perform the macro-processing step, and stop just after. Mainly useful for debugging purposes or for using the macro-processor independently of the rest of Dynare toolbox.

nolinemacro

Instructs the macro-preprocessor to omit line numbering information in the intermediary .mod file created after the macro-processing step. Useful in conjunction with savemacro when one wants that to reuse the intermediary .mod file, without having it cluttered by line numbering directives.

noemptylinemacro

Passing this option removes all empty from the macro expanded mod file created when the savemacro option is used.

onlymodel

Instructs the preprocessor to print only information about the model in the driver file; no Dynare commands (other than the shocks statement and parameter initializations) are printed and hence no computational tasks performed. The same ancillary files are created as would otherwise be created (dynamic, static files, etc.).

nolog

Instructs Dynare to no create a logfile of this run in FILENAME.log. The default is to create the logfile.

params_derivs_order=0|1|2

When identification, dynare_sensitivity (with identification), or estimation_cmd are present, this option is used to limit the order of the derivatives with respect to the parameters that are calculated by the preprocessor. 0 means no derivatives, 1 means first derivatives, and 2 means second derivatives. Default: 2

nowarn

Suppresses all warnings.

json = parse|transform|compute

Causes the preprocessor to output a version of the .mod file in JSON format.

If parse is passed, the output will be written after the parsing of the .mod file to a file called FILENAME.json.

If transform is passed, the JSON output of the transformed model (maximum lead of 1, minimum lag of -1, expectation operators substituted, etc.) will be written to a file called FILENAME.json and the original, untransformed model will be written in FILENAME_original.json.

And if compute is passed, the output is written after the computing pass. In this case, the transformed model is written to FILENAME.json, the original model is written to FILENAME_original.json, and the dynamic and static files are written to FILENAME_dynamic.json and FILENAME_static.json.

jsonstdout

Instead of writing output requested by json to files, write to standard out.

onlyjson

Quit processing once the output requested by json has been written.

jsonderivsimple

Print a simplified version (excluding variable name(s) and lag information) of the static and dynamic files in FILENAME_static.json and FILENAME_dynamic..

warn_uninit

Display a warning for each variable or parameter which is not initialized. See Parameter initialization, or load_params_and_steady_state for initialization of parameters. See Initial and terminal conditions, or load_params_and_steady_state for initialization of endogenous and exogenous variables.

console

Activate console mode. In addition to the behavior of nodisplay, Dynare will not use graphical waitbars for long computations.

nograph

Activate the nograph option (see nograph), so that Dynare will not produce any graph.

nointeractive

Instructs Dynare to not request user input.

nopathchange

By default Dynare will change Matlab/Octave’s path if dynare/matlab directory is not on top and if Dynare’s routines are overriden by routines provided in other toolboxes. If one wishes to override Dynare’s routines, the nopathchange options can be used. Alternatively, the path can be temporarly modified by the user at the top of the .mod file (using Matlab/Octave’s addpath command).

nopreprocessoroutput

Prevent Dynare from printing the output of the steps leading up to the preprocessor as well as the preprocessor output itself.

mexext=mex|mexw32|mexw64|mexmaci64|mexa64

The mex extension associated with your platform to be used when compiling output associated with use_dll. Dynare is able to set this automatically, so you should not need to set it yourself.

matlabroot=<<path>>

The path to the Matlab installation for use with use_dll. Dynare is able to set this automatically, so you should not need to set it yourself.

parallel[=CLUSTER_NAME]

Tells Dynare to perform computations in parallel. If CLUSTER_NAME is passed, Dynare will use the specified cluster to perform parallel computations. Otherwise, Dynare will use the first cluster specified in the configuration file. See The configuration file, for more information about the configuration file.

conffile=FILENAME

Specifies the location of the configuration file if it differs from the default. See The configuration file, for more information about the configuration file and its default location.

parallel_slave_open_mode

Instructs Dynare to leave the connection to the slave node open after computation is complete, closing this connection only when Dynare finishes processing.

parallel_test

Tests the parallel setup specified in the configuration file without executing the .mod file. See The configuration file, for more information about the configuration file.

-DMACRO_VARIABLE=MACRO_EXPRESSION

Defines a macro-variable from the command line (the same effect as using the Macro directive @#define in a model file, see Macro-processing language).

-I<<path>>

Defines a path to search for files to be included by the macroprocessor (using the @#include command). Multiple -I flags can be passed on the command line. The paths will be searched in the order that the -I flags are passed and the first matching file will be used. The flags passed here take priority over those passed to @#includepath.

nostrict

Allows Dynare to issue a warning and continue processing when

  1. there are more endogenous variables than equations.
  2. an undeclared symbol is assigned in initval or endval.
  3. an undeclared symbol is found in the model block in this case, it is automatically declared exogenous.
  4. exogenous variables were declared but not used in the model block.
fast

Only useful with model option use_dll. Don’t recompile the MEX files when running again the same model file and the lists of variables and the equations haven’t changed. We use a 32 bit checksum, stored in <model filename>/checksum. There is a very small probability that the preprocessor misses a change in the model. In case of doubt, re-run without the fast option.

minimal_workspace

Instructs Dynare not to write parameter assignments to parameter names in the .m file produced by the preprocessor. This is potentially useful when running dynare on a large .mod file that runs into workspace size limitations imposed by MATLAB.

compute_xrefs

Tells Dynare to compute the equation cross references, writing them to the output .m file.

stochastic

Tells Dynare that the model to be solved is stochastic. If no Dynare commands related to stochastic models (stoch_simul, estimation, …) are present in the .mod file, Dynare understands by default that the model to be solved is deterministic.

These options can be passed to the preprocessor by listing them after the name of the .mod file. They can alternatively be defined in the first line of the .mod file, this avoids typing them on the command line each time a .mod file is to be run. This line must be a Dynare comment (ie must begin with //) and the options must be comma separated between --+ options: and +--. Note that any text after the +-- will be discarded. As in the command line, if an option admits a value the equal symbol must not be surrounded by spaces. For instance json = compute is not correct, and should be written json=compute.

Output

Depending on the computing tasks requested in the .mod file, executing the dynare command will leave variables containing results in the workspace available for further processing. More details are given under the relevant computing tasks. The M_,``oo_``, and options_ structures are saved in a file called FILENAME_results.mat. If they exist, estim_params_, bayestopt_, dataset_, oo_recursive_ and estimation_info are saved in the same file.

MATLAB/Octave variable: M_

Structure containing various information about the model.

MATLAB/Octave variable: options_

Structure contains the values of the various options used by Dynare during the computation.

MATLAB/Octave variable: oo_

Structure containing the various results of the computations.

MATLAB/Octave variable: dataset_

A dseries object containing the data used for estimation.

MATLAB/Octave variable: oo_recursive_

Cell array containing the oo_ structures obtained when estimating the model for the different samples when performing recursive estimation and forecasting. The oo_ structure obtained for the sample ranging to the i -th observation is saved in the i -th field. The fields for non-estimated endpoints are empty.

Example

Call dynare from the MATLAB or Octave prompt, without or with options:

>> dynare ramst
>> dynare ramst.mod savemacro

Alternatively the options can be passed in the first line of ramst.mod:

// --+ options: savemacro, json=compute +--

and then dynare called without passing options on the command line:

>> dynare ramst

3.2. Dynare hooks

It is possible to call pre and post Dynare preprocessor hooks written as MATLAB scripts. The script MODFILENAME/hooks/priorprocessing.m is executed before the call to Dynare’s preprocessor, and can be used to programmatically transform the mod file that will be read by the preprocessor. The script MODFILENAME/hooks/postprocessing.m is gexecuted just after the call to Dynare’s preprocessor, and can be used to programmatically transform the files generated by Dynare’s preprocessor before actual computations start. The pre and/or post dynare preprocessor hooks are executed if and only if the aforementioned scripts are detected in the same folder as the the model file, FILENAME.mod.

3.3. Understanding Preprocessor Error Messages

If the preprocessor runs into an error while processing your .mod file, it will issue an error. Due to the way that a parser works, sometimes these errors can be misleading. Here, we aim to demystify these error messages.

The preprocessor issues error messages of the form:

  1. ERROR: <<file.mod>>: line A, col B: <<error message>>
  2. ERROR: <<file.mod>>: line A, cols B-C: <<error message>>
  3. ERROR: <<file.mod>>: line A, col B - line C, col D: <<error message>>

The first two errors occur on a single line, with error two spanning multiple columns. Error three spans multiple rows.

Often, the line and column numbers are precise, leading you directly to the offending syntax. Infrequently however, because of the way the parser works, this is not the case. The most common example of misleading line and column numbers (and error message for that matter) is the case of a missing semicolon, as seen in the following example:

varexo a, b
parameters c, ...;

In this case, the parser doesn’t know a semicolon is missing at the end of the varexo command until it begins parsing the second line and bumps into the parameters command. This is because we allow commands to span multiple lines and, hence, the parser cannot know that the second line will not have a semicolon on it until it gets there. Once the parser begins parsing the second line, it realizes that it has encountered a keyword, parameters, which it did not expect. Hence, it throws an error of the form: ERROR: <<file.mod>>: line 2, cols 0-9: syntax error, unexpected PARAMETERS. In this case, you would simply place a semicolon at the end of line one and the parser would continue processing.

It is also helpful to keep in mind that any piece of code that does not violate Dynare syntax, but at the same time is not recognized by the parser, is interpreted as native Matlab code. This code will be directly passed to the driver script. Investigating driver.m file then helps with debugging. Such problems most often occur when defined variable or parameter names have been misspelled so that Dynare’s parser is unable to recognize them.