> ## Documentation Index
> Fetch the complete documentation index at: https://docs.thrindex.com/llms.txt
> Use this file to discover all available pages before exploring further.

# E0109 — DelayLengthMismatch

> The delay array for a Dense layer has the wrong number of entries.

<Warning>E0109: delay array length mismatch</Warning>

## What happened

A Dense layer with delays enabled has a delay array whose length does not equal `in_features × out_features`. The delay array must have exactly one entry per connection.

## Why

The delay array is corrupt in the Graph IR. This should not occur if the model was built with `snn.Dense(..., delays=True)` using a current version of the Python SDK. If it does occur, there is a serialization bug.

## How to fix

1. **Recompile** the model from Python: `thx.compile(model, "model.thx")`.
2. If the error persists across fresh compilations, file a bug report — this indicates a serialization bug in the Python SDK.

## Example

```
E0109: delay array length mismatch in layer 0
Why: a dense delay array must have exactly in_features × out_features = 358400 entries, but it has 358399 entries.
Fix: recompile the model — the Graph IR delay data may be corrupt.
Docs: https://docs.thrindex.com/errors/E0109
```