# Run with PLUMED

**You will learn:** how to enable [PLUMED](https://www.plumed.org/) for an ACEMD run — enhanced sampling (metadynamics, steered MD), complex restraints, and on-the-fly collective-variable output.

```{note}
This page is a stub. Detailed worked examples will land in a future release; until then the PLUMED [user documentation](https://www.plumed.org/doc-v2.6/user-doc/html/) covers the input-file syntax and the available actions.
```

## Setup

Point ACEMD at a PLUMED input file via the top-level `plumedfile` key:

```{code-block} yaml
:caption: input.yaml

structure: structure.prmtop
coordinates: structure.pdb
plumedfile: plumed.dat
thermostat: true
run: 100ns
```

The `plumed.dat` file follows PLUMED's standard input syntax — no ACEMD-specific changes.

## Run

```bash
acemd
```

## Gotchas

- PLUMED uses its own atom numbering (1-based, in the topology's order). Atom indices in `plumed.dat` are independent of ACEMD's atom-selection syntax.
- The `acemd-base` package does **not** include PLUMED. Install the full `acemd` package, or install PLUMED separately and let ACEMD find it.

## See also

- `plumedfile` in [Input options](../reference/input-options.md)
- [PLUMED user documentation](https://www.plumed.org/doc-v2.6/user-doc/html/)