E0203 — OutputShapeMismatch (backend) - THRINDEX

E0203: backend output shape mismatch

What happened

A hardware backend ran inference and returned an output raster, but the raster has a different number of timesteps (got_t ≠ t) or output neurons (got_n ≠ n) than the model’s declared output shape.

Why

This is a backend implementation bug. The backend must run exactly T timesteps and return exactly N_out neurons per the artifact’s declared output layer.

How to fix

If you are integrating a hardware backend: verify that your backend’s run_batch implementation returns a tensor of shape [batch, T, N_out] where T and N_out come from the artifact.
Check for off-by-one errors in timestep unrolling.
If this occurs with a production THRINDEX release, file a bug with the artifact, target name, and the exact error message.

Example

E0203: backend output shape mismatch — expected [100, 20], got [99, 20]
Why: the backend returned fewer/more timesteps or neurons than the reference simulation
Fix: verify the backend correctly unrolls T timesteps and outputs all N_out neurons
Docs: https://docs.thrindex.com/errors/E0203

E0206 — the same check performed per-sample in the conformance harness