Documentation for the Washington-Idaho CGE Model
Gams programming documentation:
Documentation for the variables, parameters and equations in the CGE model can be found in the documentation link below. Likewise a description of the steps to create the CGE files from IMPLAN (IMPLAN TO GAMS) and the steps (STEPS) to create the social accounting matrix (SAM) and CGE model are also summarized in the links below.
Input data for the model comes from the IMPLAN program and data. A regional model may be constructed with the IMPLAN program using the social accounts option. A report can then be generated from the SAM reports tab in IMPLAN which will create the 27 CGE files that are used as input into the GAMS programs. The 27 text files created by IMPLAN are in the form of dat (text) files.
The GAMS files required to create the SAM (sam.gms) are:
- check.gms
- aggreg.gms
- map.gms
The file “model.gms” uses sam.gams to calibrate a regional CGE model and to create a counterfactual solution to the system of simultaneous non-linear equations (the model) as specified by the user. When model.gms is executed it causes report.gms to generate a text file (model report.txt) that compares baseline values of model variables with counterfactual values of those same variables.
4. model.gms
5. report.gms
6. SAM.gms
7. model report.txt
In addition to these files, an additional file “gms2xcl.gms” is available. This code takes SAM.gms and writes the SAM accounts into row/column format as an excel spreadsheet. This is helpful in viewing the individual accounts that make up the SAM.
The above programs have been tested using version 21.2 of GAMS. Versions before 21.2should work except for the gms2xcl.gms program. The GAMS gdx facility apparently will not work with earlier versions.
While the names and locations of these files can
and will be changed for various runs, it is important to insure
that the correct names and paths are inserted into the INCLUDE and
BATINCLUDE instructions within each of the programs. This is explained
further in the documentation for each program.
check.gms – This file is Rutherford’s program with minor changes by Leroy Stodick which sets up the SAM accounts as required to read the data in the 27 IMPLAN output files. Check.gms reads the IMPLAN data by using the “include” command. It is important to insure that the “include” commands in check.gms correctly point to the location of IMPLAN generated CGE files. After setting the social accounts and reading in the data, check.gms calls the aggreg.gms file by using the include command. It is important that the user sets the correct path for the aggreg.gms file in the include line in check.gms. The folder where the aggreg.gms file is located can be set using the global variable PROGPATH. This will also be the folder where the map.gms file is located and where the output file named SAM.gms will be placed.
Complete documentation of the CGE model and associated procedures may be found in the linked documents below.
Model Documentation:
August 16, 2004
