# 5. The configuration file

The configuration file is used to provide Dynare with information not related to the model (and hence not placed in the model file). At the moment, it is only used when using Dynare to run parallel computations.

On Linux and macOS, the default location of the configuration file is `$HOME/.dynare`, while on Windows it is `%APPDATA%\dynare.ini` (typically `c:\Users\USERNAME\AppData\dynare.ini`). You can specify a non standard location using the `conffile` option of the `dynare` command (see Dynare invocation).

The parsing of the configuration file is case-sensitive and it should take the following form, with each option/choice pair placed on a newline:

    [command0]
    option0 = choice0
    option1 = choice1

    [command1]
    option0 = choice0
    option1 = choice1

The configuration file follows a few conventions (self-explanatory conventions such as `USER_NAME` have been excluded for concision):

`COMPUTER_NAME`

> Indicates the valid name of a server (e.g. `localhost`, `server.cepremap.org`) or an IP address.

`DRIVE_NAME`

> Indicates a valid drive name in Windows, without the trailing colon (e.g. `C`).

`PATH`

> Indicates a valid path in the underlying operating system (e.g. `/home/user/dynare/matlab/`).

`PATH_AND_FILE`

> Indicates a valid path to a file in the underlying operating system (e.g. `/usr/local/MATLAB/R2010b/bin/matlab`).

`BOOLEAN`

> Is `true` or `false`.

## 5.1. Dynare Configuration

This section explains how to configure Dynare for general processing. Currently, there is only one option available.

Configuration block: `[hooks]`

  This block can be used to specify configuration options that will be used when running Dynare.

  Options

  `GlobalInitFile = PATH_AND_FILE`

    The location of the global initialization file to be run at the end of `global_initialization.m`.

  Example

  >     [hooks]
  >     GlobalInitFile = /home/usern/dynare/myInitFile.m

Configuration block: `[paths]`

  This block can be used to specify paths that will be used when running dynare.

  Options

  `Include = PATH`

    A colon-separated path to use when searching for files to include via `@#include`. Paths specified via `-I` take priority over paths specified here, while these paths take priority over those specified by `@#includepath`.

  Example

  >     [paths]
  >     Include = /path/to/folder/containing/modfiles:/path/to/another/folder

## 5.2. Parallel Configuration

This section explains how to configure Dynare for parallelizing some tasks which require very little inter-process communication.

The parallelization is done by running several MATLAB or Octave processes, either on local or on remote machines. Communication between master and slave processes are done through SMB on Windows and SSH on UNIX. Input and output data, and also some short status messages, are exchanged through network filesystems. Currently the system works only with homogenous grids: only Windows or only Unix machines.

The following routines are currently parallelized:

> - the posterior sampling algorithms when using multiple chains;

> - the Metropolis-Hastings diagnostics;

> - the posterior IRFs;

> - the prior and posterior statistics;

> - some plotting routines.

Note that creating the configuration file is not enough in order to trigger parallelization of the computations: you also need to specify the `parallel` option to the `dynare` command. For more details, and for other options related to the parallelization engine, see Dynare invocation.

You also need to verify that the following requirements are met by your cluster (which is composed of a master and of one or more slaves):

For a Windows grid:

> - a standard Windows network (SMB) must be in place;

> - the PsTools suite must be installed in the path of the master Windows machine;

> - the Windows user on the master machine has to be user of any other slave machine in the cluster, and that user will be used for the remote computations.

> - detailed step-by-step setup instructions can be found in Windows Step-by-Step Guide.

For a UNIX grid:

> - SSH must be installed on the master and on the slave machines;

> - SSH keys must be installed so that the SSH connection from the master to the slaves can be done without passwords, or using an SSH agent.

We now turn to the description of the configuration directives. Note that comments in the configuration file can be provided by separate lines starting with a hashtag (#).

Configuration block: `[cluster]`

  When working in parallel, `[cluster]` is required to specify the group of computers that will be used. It is required even if you are only invoking multiple processes on one computer.

  Options

  `Name = CLUSTER_NAME`

    The reference name of this cluster.

  `Members = NODE_NAME[(WEIGHT)] NODE_NAME[(WEIGHT)] ...`

    A list of nodes that comprise the cluster with an optional computing weight specified for that node. The computing weight indicates how much more powerful one node is with respect to the others (e.g. `n1(2) n2(1) n3(3)` means that `n1` is two times more powerful than `n2` whereas `n3` is three times more powerful than `n2`). Each node is separated by at least one space and the weights are in parenthesis with no spaces separating them from their node.

  Example

  >     [cluster]
  >     Name = c1
  >     Members = n1 n2 n3

  >     [cluster]
  >     Name = c2
  >     Members = n1(4) n2 n3

Configuration block: `[node]`

  When working in parallel, `[node]` is required for every computer that will be used. The options that are required differ, depending on the underlying operating system and whether you are working locally or remotely.

  Options

  `Name = NODE_NAME`

    The reference name of this node.

  `CPUnbr = INTEGER | [INTEGER:INTEGER]`

    If just one integer is passed, the number of processors to use. If a range of integers is passed, the specific processors to use (processor counting is defined to begin at one as opposed to zero). Note that using specific processors is only possible under Windows; under Linux and macOS, if a range is passed the same number of processors will be used but the range will be adjusted to begin at one.

  `ComputerName = COMPUTER_NAME`

    The name or IP address of the node. If you want to run locally, use `localhost` (case-sensitive).

  `Port = INTEGER`

    The port number to connect to on the node. The default is empty, meaning that the connection will be made to the default SSH port (22).

  `UserName = USER_NAME`

    The username used to log into a remote system. Required for remote runs on all platforms.

  `Password = PASSWORD`

    The password used to log into the remote system. Required for remote runs originating from Windows.

  `RemoteDrive = DRIVE_NAME`

    The drive to be used for remote computation. Required for remote runs originating from Windows.

  `RemoteDirectory = PATH`

    The directory to be used for remote computation. Required for remote runs on all platforms.

  `DynarePath = PATH`

    The path to the matlab subdirectory within the Dynare installation directory. The default is the empty string.

  `MatlabOctavePath = PATH_AND_FILE`

    The path to the MATLAB or Octave executable. The default value is `matlab`.

  `NumberOfThreadsPerJob = INTEGER`

    For Windows nodes, sets the number of threads assigned to each remote MATLAB/Octave run. The default value is 1.

  `SingleCompThread = BOOLEAN`

    Whether or not to disable MATLAB’s native multithreading. The default value is `false`. Option meaningless under Octave.

  `OperatingSystem = OPERATING_SYSTEM`

    The operating system associated with a node. Only necessary when creating a cluster with nodes from different operating systems. Possible values are `unix` or `windows`. There is no default value.

  Example

  >     [node]
  >     Name = n1
  >     ComputerName = localhost
  >     CPUnbr = 1

  >     [node]
  >     Name = n2
  >     ComputerName = dynserv.cepremap.org
  >     CPUnbr = 5
  >     UserName = usern
  >     RemoteDirectory = /home/usern/Remote
  >     DynarePath = /home/usern/dynare/matlab
  >     MatlabOctavePath = matlab

  >     [node]
  >     Name = n3
  >     ComputerName = dynserv.dynare.org
  >     Port = 3333
  >     CPUnbr = [2:4]
  >     UserName = usern
  >     RemoteDirectory = /home/usern/Remote
  >     DynarePath = /home/usern/dynare/matlab
  >     MatlabOctavePath = matlab

## 5.3. Windows Step-by-Step Guide

This section outlines the steps necessary on most Windows systems to set up Dynare for parallel execution.

> 1. Write a configuration file containing the options you want. A mimimum working example setting up a cluster consisting of two local CPU cores that allows for e.g. running two Monte Carlo Markov Chains in parallel is shown below.

> 2. Save the configuration file somwhere. The name and file ending do not matter if you are providing it with the `conffile` command line option. The only restrictions are that the path must be a valid filename, not contain non-alpha-numeric characters, and not contain any whitespaces. For the configuration file to be accessible without providing an explicit path at the command line, you must save it under the name `dynare.ini` into your user account’s `Application Data` folder.

> 3. Install PSTools to your system, e.g. into `C:\PSTools.`

> 4. Set the Windows System Path to the `PSTools` folder (e.g. using something along the line of pressing Windows Key+Pause to open the System Configuration, then go to Advanced -> Environment Variables -> Path).

> 5. Restart your computer to make the path change effective.

> 6. Open MATLAB and type into the command window:

>        !psexec

>    This executes the `psexec.exe` from PSTools on your system and shows whether Dynare will be able to locate it. If MATLAB complains at this stage, you did not correctly set your Windows system path for the `PSTools` folder.

> 7. If `psexec.exe` was located in the previous step, a popup will show up, asking for confirmation of the license agreement. Confirm this copyright notice of `psexec` (this needs to be done only once). After this, Dynare should be ready for parallel execution.

> 8. Call Dynare on your mod-file invoking the `parallel` option and providing the path to your configuration file with the `conffile` option (if you did not save it as `%APPDATA%\dynare.ini` in step 2 where it should be detected automatically):

>        dynare ls2003 parallel conffile='C:\Users\Dynare~1\parallel\conf_file.ini'

> Please keep in mind that no white spaces or names longer than 8 characters are allowed in the `conffile` path. The 8-character restriction can be circumvented by using the tilde Windows path notation as in the above example.

Example:

    #cluster needs to always be defined first
    [cluster]
    #Provide a name for the cluster
    Name=Local
    #declare the nodes being member of the cluster
    Members=n1

    #declare nodes (they need not all be part of a cluster)
    [node]
    #name of the node
    Name=n1
    #name of the computer (localhost for the current machine)
    ComputerName=localhost
    #cores to be included from this node
    CPUnbr=[1:2]
    #path to matlab.exe; on Windows, the MATLAB bin folder is in the system path
    #so we only need to provide the name of the exe file
    MatlabOctavePath=matlab
    #Dynare path you are using
    DynarePath=C:/dynare/4.7.0/matlab