> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.nvidia.com/nemo/automodel/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/nemo/automodel/_mcp/server.

# nemo_automodel.components.datasets.multimodal.collate_fns

Multimodal collate functions.

BAGEL uses **packed** sequences (samples concatenated along the sequence
axis with a cumulative-seqlens index), not left/right padding. The collate
function is essentially a pass-through that wraps the single packed dict
produced by :class:`PackedDataset` in a `SimpleCustomBatch` with
`pin_memory` / `cuda` helpers.

## Module Contents

### Classes

| Name                                                                                                | Description                                                               |
| --------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------- |
| [`SimpleCustomBatch`](#nemo_automodel-components-datasets-multimodal-collate_fns-SimpleCustomBatch) | Pass-through wrapper around one packed batch from :class:`PackedDataset`. |

### Functions

| Name                                                                                                            | Description                                                           |
| --------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------- |
| [`bagel_packed_collate_fn`](#nemo_automodel-components-datasets-multimodal-collate_fns-bagel_packed_collate_fn) | Canonical name in AM's collate-fn registry.                           |
| [`collate_wrapper`](#nemo_automodel-components-datasets-multimodal-collate_fns-collate_wrapper)                 | Return the BAGEL-style identity collate (wraps a single packed dict). |

### API

```python
class nemo_automodel.components.datasets.multimodal.collate_fns.SimpleCustomBatch(
    batch
)
```

Pass-through wrapper around one packed batch from :class:`PackedDataset`.

```python
nemo_automodel.components.datasets.multimodal.collate_fns.SimpleCustomBatch.cuda(
    device
)
```

```python
nemo_automodel.components.datasets.multimodal.collate_fns.SimpleCustomBatch.pin_memory()
```

```python
nemo_automodel.components.datasets.multimodal.collate_fns.SimpleCustomBatch.to_dict()
```

```python
nemo_automodel.components.datasets.multimodal.collate_fns.bagel_packed_collate_fn(
    batch
)
```

Canonical name in AM's collate-fn registry.

```python
nemo_automodel.components.datasets.multimodal.collate_fns.collate_wrapper()
```

Return the BAGEL-style identity collate (wraps a single packed dict).