Harrison/gpt4all (#2366)

Co-authored-by: William FH <13333726+hinthornw@users.noreply.github.com>
Co-authored-by: Eugene Yurtsev <eyurtsev@gmail.com>

docs/ecosystem/gpt4all.md

@@ -0,0 +1,37 @@
+# GPT4All
+
+This page covers how to use the `GPT4All` wrapper within LangChain.
+It is broken into two parts: installation and setup, and then usage with an example.
+
+## Installation and Setup
+- Install the Python package with `pip install pyllamacpp`
+- Download a [GPT4All model](https://github.com/nomic-ai/gpt4all) and place it in your desired directory
+
+## Usage
+
+### GPT4All
+
+To use the GPT4All wrapper, you need to provide the path to the pre-trained model file and the model's configuration.
+```python
+from langchain.llms import GPT4All
+
+# Instantiate the model
+model = GPT4All(model="./models/gpt4all-model.bin", n_ctx=512, n_threads=8)
+
+# Generate text
+response = model("Once upon a time, ")
+```
+
+You can also customize the generation parameters, such as n_predict, temp, top_p, top_k, and others.
+
+Example:
+
+```python
+model = GPT4All(model="./models/gpt4all-model.bin", n_predict=55, temp=0)
+response = model("Once upon a time, ")
+```
+## Model File
+
+You can find links to model file downloads at the [GPT4all](https://github.com/nomic-ai/gpt4all) repository. They will need to be converted to `ggml` format to work, as specified in the [pyllamacpp](https://github.com/nomic-ai/pyllamacpp) repository.
+
+For a more detailed walkthrough of this, see [this notebook](../modules/models/llms/integrations/gpt4all.ipynb)