---
myst:
  html_meta:
    description: Data samplers in PyTorch C++ — RandomSampler, SequentialSampler, DistributedRandomSampler, and StreamSampler.
    keywords: PyTorch, C++, sampler, RandomSampler, SequentialSampler, DistributedRandomSampler
---

# Samplers

Samplers control the order in which samples are accessed from a dataset.
They determine the indices that the DataLoader uses to fetch data.

## Sampler Base Class

```{doxygenclass} torch::data::samplers::Sampler
:members:
:undoc-members:
```

## Sequential Sampler

Accesses samples in order from 0 to N-1. Use this for evaluation or when
order matters.

```{doxygenclass} torch::data::samplers::SequentialSampler
:members:
:undoc-members:
```

## Random Sampler

Accesses samples in random order. Use this for training to ensure the model
sees samples in different orders each epoch.

```{doxygenclass} torch::data::samplers::RandomSampler
:members:
:undoc-members:
```

## Distributed Random Sampler

For distributed training, ensures each process gets a different subset of
the data without overlap.

```{doxygenclass} torch::data::samplers::DistributedRandomSampler
:members:
:undoc-members:
```

## Distributed Sampler (Base)

```{doxygenclass} torch::data::samplers::DistributedSampler
:members:
:undoc-members:
```

## Distributed Sequential Sampler

```{doxygenclass} torch::data::samplers::DistributedSequentialSampler
:members:
:undoc-members:
```

## Stream Sampler

```{doxygenclass} torch::data::samplers::StreamSampler
:members:
:undoc-members:
```