Dynamic Information Files

These files (which have suffix .DIN, and are text files) specify the dynamic properties of a model (that is, how it is solved in a year-on-year fashion).

For many (perhaps most) models, a Dynamic Information file is not required. [If RunDynam tells you when starting up that there is no Dynamic Information file for the model you are working with, just continue. If in any doubt, contact the researchers who prepared the model for you.]

The name of the Dynamic Information (DIN) file must be the same as the name of model except for the file suffix which must be .DIN. For example,

•if your model is TABLO-generated program c:\mymodel\model.exe then the DIN file must be c:\mymodel\model.din

•if your model is based on GEMSIM Auxiliary files c:\mymodel\model.gss and c:\mymodel\model.gst then the DIN file must be c:\mymodel\model.din

A Dynamic Information File is only required if one or more of the following hold:

•two or more logical file names have identical first 3 characters.

•you want to specify a 3-letter key for one data file which is not just the first 3 characters of its logical name.

•one or more data files is used as a lagged file.

•two or more logical files are usually associated with the same actual file.

•files created in one run (for example, the base case) are used as the input files for one logical file in another run (for example, the policy deviation).

Syntax for 3-Character Keys

Normally RunDynam takes the first 3 letters of each logical file name as the key to be used in making up names for the updated versions of this data. If you want to change this 3-character key for a logical file, put a line

file <logical_name> key <3-character-key> ;

into the Dynamic Information file. For example,

File BASDATA key BSD ;

Example. In the MONASH model, there are files with logical names EXTRA, EXTRA3, EXTRA4 and EXTRA5. Since the first 3 letters of these are the same, the DIN file for MONASH must specify different 3-character keys. The relevant parts of MONASH.DIN to fix this are:

File EXTRA key EXT ;

File EXTRA3 key EX3 ;

File EXTRA4 key EX4 ;

File EXTRA5 key EX5 ;

[If you look in MONASH.DIN you will find these parts. You will also see other things about lagged-input and usage which are not fully documented here.]

Role, Lags and Usage

These are somewhat complicated pieces of information about a dynamic model which may need to be communicated to RunDynam via the DIN file. See here for details.

Syntax Rules

Each line of the DIN file must be of the form:

file <logical_name> key <3-character-key> [lagof <logical_name2>] [role <role_word>] [usage <logical_name3> dd1 dd2 dd3] ;

where

•text inside square brackets [] is optional,

•role_word is one of "lagged-input" or "constant-input",

•dd1, dd2 and dd3 are integers between 1 and 3. In practice, dd1 must be 1, dd2 must be 2 and dd3 can be either 1 or 2 or 3.

•In practice, logical_name3 is the same as logical_name2.

Change to DIN file syntax

With Version 1.4 (February 2000) there have been small changes in the syntax of Dynamic Information files to make them more robust and easier to use. If you encounter an error reading an old Dynamic Information file, this may be the reason. [It is easy to change the file to conform to the new syntax.]

The developers will assist you in creating such a file for your model (if you need one).

URL of this topic: www.copsmodels.com/webhelp/rundynam/hc_dinfile.htm

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