Gempack

Abstract: GEMPACK is a suite of general-purpose economic modelling software especially suitable for general and partial equilibrium models. It can handle a wide range of economic behaviour and also contains a versatile method for solving intertemporal models. GEMPACK provides software for calculating accurate solutions of an economic model, starting from an algebraic representation of the equations of the model. These equations can be written as levels equations, linearized equations or a mixture of these two. The software provides a range of utility programs for handling the economic data base and the results of simulations, and is fully documented from a user's point of view. GEMPACK is used to implement and solve a number of economic models including several single-country models (of which the ORANI model of Australia is perhaps the best known), multi-country trade models, regional models and intertemporal (or dynamic) models. GEMPACK runs on a wide variety of computers including 80386/80486 microcomputers running DOS, Windows or OS/2, Apple Macintosh computers, Unix machines, DEC VAX and Alpha machines running VMS. This paper gives an overview of the current release of GEMPACK (Release 5.1, April 1994). Included are descriptions of the algebra-like language used to describe and document the equations of an economic model, the operation of the pre-processor TABLO which converts the equations of the model to a form suitable for computing solutions of the model, the solution methods used for producing accurate solutions of the model, the facilities for specifying and carrying out simulations, including the options for varying the choice of endogenous and exogenous variables and the variables shocked, the condensation facility which makes it possible to solve very large models, the utility programs for assisting in managing the data bases on which models are based, the different versions of GEMPACK.

Abstract: Preface. Chapter 1: Aims, Background, Innovations and Presentation. Introduction. Background and Innovations. Presentation, Computer Code, Reading Strategy and Themes. Chapter 2: An Illustrative Application of MONASH: the Australian Motor Vehicle Industry from 1987 to 2016. Introduction. Historical and Decomposition Simulations: The Australian Motor Vehicle Industry from 1987 to 1994. Forecast Simulation: Prospects for the Australian Motor Vehicle Industry, 1998 to 2016. A Policy Simulation: The Effects of Reductions in the Tariff on Motor Vehicles. Policy Implications and Concluding Remarks. Appendix: The Derivation of the Formulas for Analysing the Difference Between GDP Paths in Alternative Simulations. Chapter 3: Mathematical Structure, Solution Algorithm and Computer Implementation: An Overview. Introduction. Overview of the Mathematical Structure of MONASH and Introduction to the Johansen/Euler Solution Method. The Input-Output Database and the Initial Solution. Evaluation of the Coefficients in Linear Systems such as (11.2) and (11.12). Overview of the GEMPACK Computations for the MONASH Model. Chapter 4: The Theory of the MONASH Model. Introduction. A Schematic Version of the MONASH Model. Results of Optimizing Decisions. Demands for Exports. Indirect Taxes. Definitions of Macro Variable: Interpretation of Divisia Indexes. Capital-Supply Functions, Rates of Return and Forward-Looking Expectations. Computational Strategy for Decomposition Simulations: Halfway Databases. Equations for Facilitating Historical and Forecast Simulations. Wage Adjustment and Welfare Measures in Policy Simulations. The Public-Sector Account, the Current Account and the Household Account. Appendix: CRESH Production Functions and CRETH Transformation Frontiers. Appendix: The Theory Underlying the Demand Equations for Traditional Exports. Appendix: The Levels representation of Price and Quantity Indexes in MONASH. Chapter 5: Developing the MONASH Closures. Introduction. The Decomposition closure (Third Column of Table 30.1). Developing the Historical Closure (Fourth Column of Table 30.1). Developing the Forecast Closure (Second Column of Table 30.1). Developing the Policy Closure (First Column of Table 30.1). MONASH Closures: Concluding Remarks. Chapter 6: Extensions, Progress and the Future. Introduction. Generating Results for Sub-National Regions. Generating Results for Detailed Occupations. Generating Output Results at a Sub-Input-Output Level. Generating Distributional Results: The Real Incomes of Many Types of Households. Quantifying Labour Market Adjustment Costs. Progress and the Future. References. Author Index. Subject Index.

Abstract: This paper gives a brief overview of a new suite of software designed to make it relatively painless to implement large economic models, especially those in the computable general equilibrium (CGE) class. Whereas in the past a large element in the cost of building these models has been the writing of special-purpose code, the GEMPACK facility described here virtually eliminates the need for tailor-made programs. Moreover, because this facility is accessed via an essentially algebraic language, the GEMPACK computer text file used to implement an economic model provides an easily understood, but exhaustive and definitive, documentation of the model itself — something which only rarely has been available in the past.