> For the complete documentation index, see [llms.txt](https://docs.sdv.dev/sdgym/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sdv.dev/sdgym/customization/synthesizers/basic-synthesizers.md).

# Basic Synthesizers

The SDGym library includes some basic synthesizers that you can use for benchmarking purposes. Pass the string names into the `synthesizers` parameter.

```python
import sdgym

sdgym.benchmark_single_table(
    synthesizers=['DataIdentity', 'UniformSynthesizer']
)
```

{% hint style="warning" %}
**Use basic synthesizers for comparison purposes only!** The basic synthesizers listed below are likely not great candidates for creating usable synthetic data. Use them as comparisons with other synthesizers, such as [SDV Synthesizers](/sdgym/customization/synthesizers/sdv-synthesizers.md).
{% endhint %}

## Basic Single-Table Synthesizers

<table><thead><tr><th width="239.6171875">Basic Synthesizer</th><th>Description</th></tr></thead><tbody><tr><td>DataIdentity</td><td>This synthesizer* returns the same data that it receives. It serves as an identity function.<br><em>*Technically, this technique doesn't really count as a synthesizer as it does not create new data</em></td></tr><tr><td>UniformSynthesizer</td><td>This synthesizer learns the numerical ranges or categories of each column. Then, it creates synthetic data by randomly generating values within the boundaries.</td></tr><tr><td>ColumnSynthesizer</td><td>This synthesizer learns the marginal distributions of each column independently to generate synthetic data. For numerical columns, it learns a <a href="https://scikit-learn.org/stable/modules/generated/sklearn.mixture.GaussianMixture.html">Gaussian Mixture</a>. For categorical columns, it learns the frequencies of each category. This synthesizer does <em>not</em> learn any correlations between the different columns.</td></tr></tbody></table>

## Basic Multi-Table Synthesizers

<table><thead><tr><th width="240.05078125">Basic Synthesizer</th><th>Description</th></tr></thead><tbody><tr><td>MultiTableUniformSynthesizer</td><td>This synthesizer learns the numerical ranges or categories of each column. Then, it creates synthetic data by randomly generating values within the boundaries.<br><br>This synthesizer also randomly creates ID columns (primary and foreign key columns). It does not ensure that the connections or valid, or that referential integrity is held.</td></tr></tbody></table>

## FAQs

<details>

<summary>What if I have an idea for another basic synthesizer?</summary>

If there are other basic techniques you'd like to see included in the SDGym library, please [create a Feature Request](https://github.com/sdv-dev/SDGym/issues/new/choose) with your ideas.

In the meantime, you can create a [Custom Synthesizer](/sdgym/customization/synthesizers/custom-synthesizers.md) where you can implement the techniques.

</details>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.sdv.dev/sdgym/customization/synthesizers/basic-synthesizers.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.