GTAP Products: Product Requirements
The standard GTAP Model is implemented using GEMPACK (General Equilibrium Modelling Package) and therefore a GEMPACK license is required to modify the standard GTAP Model. The Centre of Policy Studies (CoPS), Australia develops and supports GEMPACK. GEMPACK licenses must be obtained from CoPS.
Supplied with RunGTAP are the current version of the GTAP Model (GTAP.TAB), a standard condensation of the model (GTAP.STI), and the associated GTAP.EXE, which is used to solve the model. If you do not want to omit or backsolve/substitute any of the variables, you may use the uncondensed version of the GTAP Model (GTAPu.TAB and GTAPu.EXE), which is also available with RunGTAP. If you need to change the theory of the model (that is, change GTAP.TAB) or if you need to change the condensation (for example, to un-omit/omit different variables or to do different substitutions or backsolves), you need to change GTAP.EXE. You can only do that if you have a GEMPACK license since you will need to run the GEMPACK program TABLO. More precisely,
- You can make a new GTAP.EXE if you have a Source-Code Version of GEMPACK.
- If you have an Executable-Image Version of GEMPACK, you can solve GTAP using the GEMPACK program GEMSIM. Then you need to run TABLO to produce the GEMSIM Auxiliary files GTAP.GSS and GTAP.GST (which reflect your modified TAB file and/or condensation).
- If you have only the Limited Executable-Image Version (this is the version supplied at the GTAP Short Courses), you will only be able to solve for up to about 9x9 (or even smaller if you un-omit variables).
- But you can solve for any aggregation if you have the Unlimited Executable-Image Version of GEMPACK.
You will find further information about GEMPACK at the CoPS website, which also has specific advice for GTAP users, and a useful Summary of GEMPACK Versions. Those interested in opening the HAR and Sl4 files available under the resources sections on this site should download these free GEMPACK programs.
What Do I Need?
Which package to choose will depend on your needs and on your previous modeling experience. There are different requirements depending on whether you wish to modify the standard GTAP Model and if you need to work with aggregations of the GTAP Data Base beyond 10 sectors and/or 10 regions. See this advice for GTAP users.