modelica_ir

JSON schemas for Modelica intermediate representations.

Schemas

Schema	Description	Use Case
Explicit IR	Causal ODE: dx/dt = f(x,u,p)	Real-time code generation, embedded systems
DAE IR	Implicit DAE with classified variables	Simulation with DAE solvers, analysis
Base Modelica IR	MCP-0031 compliant flat format	Tool interoperability
Full Modelica IR	Complete Modelica 3.7 representation	IDE tools, analysis

Pipeline

Modelica source → Rumoca → Explicit IR (causal) or DAE IR (implicit) → Cyecca/Solver

• Explicit IR: Result of BLT + causalization. No algebraic loops. Ready for C code generation.
• DAE IR: Implicit models with algebraic constraints. Requires DAE solver.

Explicit IR Example

{
  "ir_version": "explicit-0.1.0",
  "model_name": "MassSpring",
  "states": [
    {"name": "x", "index": 0, "start": 1.0},
    {"name": "v", "index": 1, "start": 0.0}
  ],
  "parameters": [
    {"name": "k", "index": 0, "value": 1.0}
  ],
  "derivatives": [
    {"state_index": 0, "expr": {"op": "state_ref", "ref_index": 1}},
    {"state_index": 1, "expr": {"op": "*", "args": [{"op": "literal", "value": -1}, {"op": "param_ref", "ref_index": 0}, {"op": "state_ref", "ref_index": 0}]}}
  ]
}

DAE IR Example

{
  "ir_version": "dae-0.1.0",
  "model_name": "BouncingBall",
  "variables": {
    "states": [{"name": "h", "state_index": 0, "start": 1.0}],
    "algebraic": [],
    "parameters": [{"name": "g", "start": 9.81}]
  },
  "equations": {
    "continuous": [
      {"eq_type": "simple", "lhs": {"op": "der", "args": [{"op": "component_ref", "parts": [{"name": "h"}]}]}, "rhs": {"op": "component_ref", "parts": [{"name": "v"}]}}
    ]
  }
}

Validation

python tools/validate.py examples/bouncing_ball_dae.json

Related Projects

• Rumoca - Modelica compiler (produces these IRs)
• Cyecca - Simulation/analysis tool (consumes these IRs)

License

See LICENSE