Quickstart

This page walks through a first successful COBRA run.

1. Prepare Inputs

You need:

• A netlist file (.cir / .sp) compatible with Xyce parsing.
• At least one component mapping to either:
• ONNX surrogate model (.onnx), or
• fixed Touchstone model (.sNp).

For an immediate starting point, use files in examples/.

2. Run GUI Mode

cobra

In GUI mode:

1. Load netlist.
2. Map each parsed component to model source files.
3. Define design goals.
4. Define optimization parameters.
5. Start optimization.

3. Run Script Mode (Optional)

python examples/main.py

This script demonstrates:

• mixed model sources (.onnx + .sNp),
• MODEL_INPUT and NETLIST_VARIABLE optimization,
• linked variables,
• OptunaOptimizer + XyceSimulator,
• optional ORCA geometry argument.

For concept details (workflow, goals, parameter types), see Home.

4. Inspect Results

Each run creates a timestamped folder under results/:

results/<timestamp>_<name>/

Typical contents include:

• cobra_optimization_context.json
• <component>_predicted.sNp
• surrogate_s_params_<component>.sNp
• vector-fitted .sp files for simulation

Tip

Keep the generated context JSON when comparing optimization runs. It contains trial history and best parameters.

5. Common First-Run Checks

• cobra command opens the GUI.
• Xyce is discoverable in PATH.
• Netlist component names match mapping keys (e.g. X1, X2).
• File paths in script mode are absolute or correctly resolved.