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name: structured-modeling description: "Guides Pyomo users through GDP, DAE, network, MPEC, and units-based structured modeling workflows." disable-model-invocation: true metadata: disco-role: operating license: NOASSERTION

Structured Modeling

Use this sub-skill when the task uses one of Pyomo's structured modeling families instead of a plain algebraic model.

What this sub-skill covers

• GDP with Disjunct, Disjunction, and GDP transformations.
• DAE with ContinuousSet, DerivativeVar, Integral, and discretization.
• Network models with Port, Arc, and SequentialDecomposition.
• MPEC and complementarity modeling.
• Units of measure and consistency checks.

What to route elsewhere

• Core component syntax and basic model inspection go to modeling-basics.
• Data-file loading for structured models goes to data-and-io.
• Solver, CLI, and smoke-check issues go to solve-and-cli.
• APPSI, PyNumero, FBBT, simplification, community detection, or viewer issues go to solver-extensions.

Read these references

• ../../references/structured-modeling.md for the verified workflow patterns and common gotchas.
• ../../references/core-modeling.md when a structured model still needs the base component syntax.
• ../../references/troubleshooting.md when a transformation or unit check fails.

Typical workflow

1. Build the underlying Pyomo model with the normal component types.
2. Add the structured feature: disjunction, continuous set, port/arc, or complementarity relation.
3. Apply the required transformation or discretization.
4. Inspect the transformed model before solving.
5. Only then hand the model to a solver or analysis tool.

Common request patterns

• "How do I model an either-or choice with GDP?"
• "How do I discretize a DAE model?"
• "How do I expand arcs in a network model?"
• "How do I represent a complementarity condition?"
• "How do I check units on a Pyomo expression?"

Common failure modes

• Forgetting the transformation step before solving.
• Using a ContinuousSet without discretization.
• Misspelling a transformation name such as dae.collocation or network.expand_arcs.
• Building a GDP model but never choosing a GDP reformulation.
• Unit inconsistency, especially around offset temperature units.

Practical guidance

• Keep the structured example tiny until the transformation path is verified.
• Use the explicit transformation name in the example so the routing is clear.
• For DAE, always show the discretization call next to the model.
• For network models, show arc expansion before any sequential decomposition.
• For units, show the unit check alongside the expression being validated.

Examples of what belongs here

• A GDP model with two disjuncts and a single disjunction.
• A DAE model discretized with finite difference or collocation.
• A flow network with ports, arcs, and an arc-expansion transform.
• A complementarity relation or units-consistency check.

Examples of what does not belong here

• General solver configuration or CLI usage.
• Plain set/var/constraint syntax.
• Optional extension troubleshooting that is not tied to the structured model family itself.

Related routes

• Move to modeling-basics when you only need the base components.
• Move to solver-extensions when the structured model depends on optional backends or advanced solver helpers.