JCGEExamples

What is a CGE?

A Computable General Equilibrium (CGE) model is a quantitative economic model that represents an economy as interconnected markets for goods and services, factors of production, institutions, and the rest of the world. It is calibrated with data (typically a Social Accounting Matrix) and solved numerically as a system of nonlinear equations until equilibrium conditions (zero-profit, market-clearing, and income-balance) hold within tolerance.

What is JCGE?

JCGE is a block-based CGE modeling and execution framework in Julia. It defines a shared RunSpec structure and reusable blocks so models can be assembled, validated, solved, and compared consistently across packages.

What is this package?

A package that bundles model definitions (as submodules) for the JCGE ecosystem.

What belongs here

• Named model modules implemented as Julia submodules.
• Model constructors returning a spec or builder object (recommended: RunSpec/ModelSpec + optional default scenarios).
• Small toy datasets that are safe to ship in-repo (optional), under models/<ModelName>/data/.

What does NOT belong here

• Core framework code (data model, calibration, runtime, generic blocks): those stay in JCGECore, JCGECalibrate, JCGERuntime, JCGEBlocks, JCGEOutput, JCGEAgentInterface, JCGEImportMPSGE, JCGEImportData.
• Large, licensed, or country SAM datasets unless distribution rights are clear.
• Solver-specific configuration that is not part of the model definition.

Expected user-facing usage

Typical usage should look like:

• using JCGEExamples
• using JCGEExamples.<ModelName>
• spec = <ModelName>.model() (returns a spec/object that the framework can build/run)

RunSpec sections (model structure)

Models are assembled via named sections to enforce a consistent RunSpec skeleton. Canonical section names:

• :production, :factors, :government, :savings, :households, :prices, :external, :trade, :markets, :objective, :init, :closure

All sections should be present (empty is allowed), and the following must be non-empty:

• :production, :households, :markets

Folder layout

• src/: package module entrypoint
• models/<ModelName>/: module file and all model-specific resources
  • models/<ModelName>/<ModelName>.jl: model submodule
  • models/<ModelName>/data/: optional small benchmark inputs
  • models/<ModelName>/docs/: optional model notes and documentation

Models

• StandardCGE: Chapter 6, Hosoe, N, Gasawa, K, and Hashimoto, H. Handbook of Computable General Equilibrium Modeling. University of Tokyo Press, Tokyo, Japan, 2004.
• SimpleCGE: Chapter 5, Hosoe, N, Gasawa, K, and Hashimoto, H. Handbook of Computable General Equilibrium Modeling. University of Tokyo Press, Tokyo, Japan, 2004.
• LargeCountryCGE: Chapter 10.2, Hosoe, N, Gasawa, K, and Hashimoto, H. Handbook of Computable General Equilibrium Modeling. University of Tokyo Press, Tokyo, Japan, 2004.
• TwoCountryCGE: Chapter 10.3, Hosoe, N, Gasawa, K, and Hashimoto, H. Handbook of Computable General Equilibrium Modeling. University of Tokyo Press, Tokyo, Japan, 2004.
• MonopolyCGE: Chapter 10.4, Hosoe, N, Gasawa, K, and Hashimoto, H. Handbook of Computable General Equilibrium Modeling. University of Tokyo Press, Tokyo, Japan, 2004.
• QuotaCGE: Chapter 10.5, Hosoe, N, Gasawa, K, and Hashimoto, H. Handbook of Computable General Equilibrium Modeling. University of Tokyo Press, Tokyo, Japan, 2004.
• ScaleEconomyCGE: Chapter 10.6, Hosoe, N, Gasawa, K, and Hashimoto, H. Handbook of Computable General Equilibrium Modeling. University of Tokyo Press, Tokyo, Japan, 2004.
• DynCGE: Recursive-dynamic model, Hosoe, N., Gasawa, K., Hashimoto, H. Textbook of Computable General Equilibrium Modeling: Programming and Simulations, 2nd Edition, University of Tokyo Press. (Japanese edition)
• CamCGE: Cameroon CGE model, Condon, T, Dahl, H, and Devarajan, S. Implementing a Computable General Equilibrium Model on GAMS - The Cameroon Model. The World Bank, 1987.
• CamMGE: Cameroon CGE model, MPSGE syntax, Condon, T, Dahl, H, and Devarajan, S. Implementing a Computable General Equilibrium Model on GAMS - The Cameroon Model. The World Bank, 1987.
• CamMCP: Cameroon CGE model as MCP, Condon, T, Dahl, H, and Devarajan, S. Implementing a Computable General Equilibrium Model on GAMS - The Cameroon Model. The World Bank, 1987.
• KEHOMGE: Multiple equilibria model in MPSGE, Kehoe, T, A Numerical Investigation of the Multiplicity of Equilibria. Mathematical Programming Study 23 (1985), 240-258.
• KorCGE: Korea CGE model, Chapter 11 in Chenery et al., 1986.
• KorMCP: Korea CGE model as MCP, Chapter 11 in Chenery et al., 1986.

Optional solve tests (CI)

Solver-based tests are gated behind JCGE_SOLVE_TESTS=1 and run via a manual GitHub Actions workflow:

• Workflow name: Solve Tests
• Workflow: .github/workflows/solve-tests.yml
• Trigger: workflow_dispatch only
• Command: julia --project=packages/JCGEExamples -e 'using Pkg; Pkg.instantiate(); Pkg.test()'

MCP solver and PATH license

MCP models use PATH via PATHSolver.jl. PATH can run without a license for small instances (up to 300 variables and 2000 non-zeros); larger problems require a license.

To use a license string, either:

• set PATH_LICENSE_STRING="<LICENSE STRING>", or
• call PATHSolver.c_api_License_SetString("<LICENSE STRING>") before solving.

Running MCP models

With a license:

• PATH_LICENSE_STRING="..." JCGE_MCP_SOLVE=1 julia --project=packages/JCGEExamples -e 'using Pkg; Pkg.test()'
• or in code:

using JCGEExamples.CamMCP
result = CamMCP.solve(license_string="...")

Without a license (small problems only):

• JCGE_MCP_SOLVE=1 julia --project=packages/JCGEExamples -e 'using Pkg; Pkg.test()'
• or in code:

using JCGEExamples.CamMCP
result = CamMCP.solve()

If the problem exceeds PATH's free limits, CamMCP.solve() will error unless a license is provided.

Optional solution comparison

A separate manual workflow compares results against StandardCGE.jl and MPSGE:

• Workflow: .github/workflows/compare-solutions.yml
• Env flags: JCGE_SOLVE_TESTS=1, JCGE_COMPARE_SOLUTIONS=1

How to cite

If you use the JCGE framework, please cite:

Boero, R. JCGE - Julia Computable General Equilibrium Framework [software], 2026. DOI: 10.5281/zenodo.18282436 URL: https://JCGE.org

@software{boero_jcge_2026,
  title  = {JCGE - Julia Computable General Equilibrium Framework},
  author = {Boero, Riccardo},
  year   = {2026},
  doi    = {10.5281/zenodo.18282436},
  url    = {https://JCGE.org}
}

If you use this package, please cite:

Boero, R. JCGEExamples.jl - Reference models and examples for JCGE. [software], 2026. DOI: URL: https://Examples.JCGE.org SourceCode: https://github.com/equicirco/JCGEExamples.jl

@software{boero_jcgeexamples_2026,
  title  = {JCGEExamples.jl - Reference models and examples for JCGE.},
  author = {Boero, Riccardo},
  year   = {2026},
  doi    = {},
  url    = {https://Examples.JCGE.org}
}

If you use a specific tagged release, please cite the version DOI assigned on Zenodo for that release (preferred for exact reproducibility).