# Pre-training

### Listing the available recipes for pretraining

```bash
nemo llm pretrain --help
```

![recipe-listing](https://github.com/NVIDIA/NeMo/releases/download/v2.0.0rc0/list-recipes.png)


### Run pre-training with a default recipe

```bash
nemo llm pretrain --factory llama3_8b
```

![llama3_70b](https://github.com/NVIDIA/NeMo/releases/download/v2.0.0rc0/llama3_70b.png)

We can also call the factory function with custom parameters:

```bash
nemo llm pretrain --factory "llama3_70b(num_nodes=128)"
```

![llama3_70b-128-nodes](https://github.com/NVIDIA/NeMo/releases/download/v2.0.0rc0/llama3_70b_128nodes.png)


The CLI allows you to overwrite any parameter. For example, to run the recipe with 2000 steps: 

```bash
nemo llm pretrain --factory llama3_70b trainer.max_steps=2000
```

The syntax of the CLI is the same as the Python code. Which is great but in some cases you might want to inspect & edit a recipe interactively. An easy way to do this using the cli is the use the `--repl` flag.

```bash
nemo llm pretrain --factory llama3_70b --repl
```

![repl](https://github.com/NVIDIA/NeMo/releases/download/v2.0.0rc0/repl.gif)

We can also trigger a run from a jupyter notebook, see [pretrain.ipynb](pretrain.ipynb) for an example. This allows visualizes all configs in a structured format. See for instance the `llama3_8b` recipe:

![llama3_8b_visualization](https://github.com/NVIDIA/NeMo/releases/download/v2.0.0rc0/llama3_8b_config.svg)


### Create and run a custom recipe

We can create a script that contains a custom recipe. See [custom_recipe.py](custom_recipe.py) for an example.

Note that we end the script with a call to `run.cli.main()`, which uses the same syntax as the CLI but allows us to provide specific defaults. We still can overwrite any parameter using the syntax `param=value`. We can set nested parameters using dotted notation, e.g. `trainer.max_steps=2000`.

When running the custom_recipe.py file, it will execute the `custom_llama3_8b` recipe by default. However, you can select different recipes or modify parameters using the following methods:

1. To select the `custom_llama3_70b` recipe:
   ```bash
   python custom_recipe.py --factory custom_llama3_70b
   ```
   This will automatically call the `custom_llama3_70b` function defined in the script.

2. To overwrite any parameter:
   ```bash
   python custom_recipe.py trainer.max_steps=2000
   ```

3. You can even apply transformations when triggering the CLI as if it's Python code:
   ```bash
   python custom_recipe.py "trainer.max_steps=*2"
   ```

These options provide flexibility in customizing your pretraining recipe directly from the command line.