# Quick Tour

> [!TIP]
> We recommend using the `--help` flag to get more information about the
> available options for each command.
> `lighteval --help`

Lighteval can be used with several different commands, each optimized for different evaluation scenarios.

## Available Commands

### Evaluation Backends

- `lighteval accelerate`: Evaluate models on CPU or one or more GPUs using [🤗
  Accelerate](https://github.com/huggingface/accelerate)
- `lighteval nanotron`: Evaluate models in distributed settings using [⚡️
  Nanotron](https://github.com/huggingface/nanotron)
- `lighteval vllm`: Evaluate models on one or more GPUs using [🚀
  VLLM](https://github.com/vllm-project/vllm)
- `lighteval custom`: Evaluate custom models (can be anything)
- `lighteval sglang`: Evaluate models using [SGLang](https://github.com/sgl-project/sglang) as backend
- `lighteval endpoint`: Evaluate models using various endpoints as backend
  - `lighteval endpoint inference-endpoint`: Evaluate models using Hugging Face's [Inference Endpoints API](https://huggingface.co/inference-endpoints/dedicated)
  - `lighteval endpoint tgi`: Evaluate models using [🔗 Text Generation Inference](https://huggingface.co/docs/text-generation-inference/en/index) running locally
  - `lighteval endpoint litellm`: Evaluate models on any compatible API using [LiteLLM](https://www.litellm.ai/)
  - `lighteval endpoint inference-providers`: Evaluate models using [HuggingFace's inference providers](https://huggingface.co/docs/inference-providers/en/index) as backend

### Evaluation Utils

- `lighteval baseline`: Compute baselines for given tasks

### Utils

- `lighteval tasks`: List or inspect tasks
  - `lighteval tasks list`: List all available tasks
  - `lighteval tasks inspect`: Inspect a specific task to see its configuration and samples
  - `lighteval tasks create`: Create a new task from a template

## Basic Usage

To evaluate `GPT-2` on the Truthful QA benchmark with [🤗
  Accelerate](https://github.com/huggingface/accelerate), run:

```bash
lighteval accelerate \
     "model_name=openai-community/gpt2" \
     "leaderboard|truthfulqa:mc|0"
```

Here, we first choose a backend (either `accelerate`, `nanotron`, `endpoint`, or `vllm`), and then specify the model and task(s) to run.

### Task Specification

The syntax for the task specification might be a bit hard to grasp at first. The format is as follows:

```txt
{suite}|{task}|{num_few_shot}
```

Tasks have a function applied at the sample level and one at the corpus level. For example,
- an exact match can be applied per sample, then averaged over the corpus to give the final score
- samples can be left untouched before applying Corpus BLEU at the corpus level
etc.

If the task you are looking at has a sample level function (`sample_level_fn`) which can be parametrized, you can pass parameters in the CLI.
For example
```txt
{suite}|{task}@{parameter_name1}={value1}@{parameter_name2}={value2},...|0
```

All officially supported tasks can be found at the [tasks_list](available-tasks) and in the
[extended folder](https://github.com/huggingface/lighteval/tree/main/src/lighteval/tasks/extended).
Moreover, community-provided tasks can be found in the
[community](https://github.com/huggingface/lighteval/tree/main/community_tasks) folder.

For more details on the implementation of the tasks, such as how prompts are constructed or which metrics are used, you can examine the
[implementation file](https://github.com/huggingface/lighteval/blob/main/src/lighteval/tasks/default_tasks.py).

### Running Multiple Tasks

Running multiple tasks is supported, either with a comma-separated list or by specifying a file path.
The file should be structured like [examples/tasks/recommended_set.txt](https://github.com/huggingface/lighteval/blob/main/examples/tasks/recommended_set.txt).
When specifying a path to a file, it should start with `./`.

```bash
lighteval accelerate \
     "model_name=openai-community/gpt2" \
     ./path/to/lighteval/examples/tasks/recommended_set.txt
# or, e.g., "leaderboard|truthfulqa:mc|0,leaderboard|gsm8k|3"
```

## Backend Configuration

### General Information

The `model-args` argument takes a string representing a list of model
arguments. The arguments allowed vary depending on the backend you use and
correspond to the fields of the model configurations.

The model configurations can be found [here](./package_reference/models).

All models allow you to post-process your reasoning model predictions
to remove the thinking tokens from the trace used to compute the metrics,
using `--remove-reasoning-tags` and `--reasoning-tags` to specify which
reasoning tags to remove (defaults to `<think>` and `</think>`).

Here's an example with `mistralai/Magistral-Small-2507` which outputs custom
thinking tokens:

```bash
lighteval vllm \
    "model_name=mistralai/Magistral-Small-2507,dtype=float16,data_parallel_size=4" \
    "lighteval|aime24|0" \
    --remove-reasoning-tags \
    --reasoning-tags="[('[THINK]','[/THINK]')]"
```

### Nanotron

To evaluate a model trained with Nanotron on a single GPU:

> [!WARNING]
> Nanotron models cannot be evaluated without torchrun.

```bash
torchrun --standalone --nnodes=1 --nproc-per-node=1 \
    src/lighteval/__main__.py nanotron \
    --checkpoint-config-path ../nanotron/checkpoints/10/config.yaml \
    --lighteval-config-path examples/nanotron/lighteval_config_override_template.yaml
```

The `nproc-per-node` argument should match the data, tensor, and pipeline
parallelism configured in the `lighteval_config_template.yaml` file.
That is: `nproc-per-node = data_parallelism * tensor_parallelism *
pipeline_parallelism`.


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