> ## 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.

# E0005 — InvalidLifParam

> A LIF layer in the artifact has a parameter value outside the valid range.

<Warning>E0005: invalid LIF parameter</Warning>

## What happened

A LIF layer in the artifact has a parameter (`alpha`, `threshold`, or `beta`) with a value that the simulator cannot use.

## Why

Common causes:

* `alpha` is not in `(0, 1)` — this means the leak factor is non-physical (exponential amplification or no decay)
* `threshold` is ≤ 0 — a non-positive threshold fires immediately or never
* `beta` is not in `(0, 1)` — same issue as `alpha` for the synaptic filter

## How to fix

1. Check the model's `tau_mem` and `dt` values. If `tau_mem` is very small relative to `dt`, `alpha = exp(-dt/tau_mem)` approaches 0 and the compiler should have raised [E0101](/errors/E0101). If you see E0005 at runtime, the artifact may be from an older compiler build that did not validate this.
2. Recompile with the current thrindex version: `thx.compile(model, "model.thx")`.

## Example

```
E0005: invalid LIF parameter in layer 1: alpha=0.0
Why: alpha must be in (0, 1); value 0.0 would produce a trivial neuron.
Fix: set tau_mem > dt when constructing the LIF layer.
Docs: https://docs.thrindex.com/errors/E0005
```

## Related

* [E0101](/errors/E0101) — the compiler-time check for `tau_mem ≤ dt`