Solving applied general equilibrium models represented as a mixture of linearized and levels equations

General equilibrium models are usually represented as a system of levels equations (e.g. in North America) or a system of linearized equations (e.g. in Australia). Either representation can be used to obtain accurate solutions. General-purpose software is available in both cases — GAMS or MPS/GE for levels modellers and GEMPACK for linearizers. Some equations (notably accounting identities) are naturally expressed in the levels while others (especially behavioural equations) are naturally expressed in a linearized form. This paper describes the new GEMPACK facility for solving models represented as a mixture of levels and linearized equations and discusses the advantages to modellers of using such a representation.