FAQ

Can I use COBRA without the GUI?

Yes. Script mode is fully supported. Start with Getting Started -> Quickstart.

Can I mix ONNX and Touchstone components?

Yes. Map each component to either .onnx or fixed .sNp in the same run.

Can I optimize large-signal behavior?

Yes, through Harmonic Balance or a transient analysis. If the netlist contains a .HB or .TRAN analysis, COBRA exposes output-power, gain and isolation goals at any node that has both a voltage label and a current probe, and plots the resulting spectrum live. See Advanced -> Harmonic Balance and Advanced -> Transient Analysis.

Can S-parameter and Harmonic Balance goals be combined?

Yes. COBRA runs one simulation per required analysis type and aggregates all penalties into a single loss, so matching (.AC) and conversion gain or isolation (.HB) can be optimized together.

How do I target a single frequency instead of a band?

Set the same value for the minimum and maximum frequency of the goal. The nearest point of the sweep or spectrum is used.

Is transient simulation supported?

Yes. The settled part of the waveform (from the .TRAN start time on) is turned into a spectrum by an FFT, and the TRAN:-prefixed power, gain and isolation goals read it exactly like their HB counterparts. The .PRINT tran line must use format=csv. See Advanced -> Transient Analysis.

Is ORCA required?

Not for core surrogate optimization with existing ONNX files.

ORCA is required if you need ORCA geometry classes/workflows, especially for fine-tuning scenarios.

Is Palace required?

No. Palace is optional and only needed for EM fine-tuning.

Which optimizer should I start with?

Start with OptunaOptimizer (sampler="tpe") for most cases.

Where are outputs saved?

COBRA writes each run to a timestamped directory under results/.

How do I keep symmetric constraints?

Use linked_to in OptimizationProperty so one variable mirrors another.