langchain/docs/modules/chains/key_concepts.md
Harrison Chase 985496f4be
Docs refactor (#480)
Big docs refactor! Motivation is to make it easier for people to find
resources they are looking for. To accomplish this, there are now three
main sections:

- Getting Started: steps for getting started, walking through most core
functionality
- Modules: these are different modules of functionality that langchain
provides. Each part here has a "getting started", "how to", "key
concepts" and "reference" section (except in a few select cases where it
didnt easily fit).
- Use Cases: this is to separate use cases (like summarization, question
answering, evaluation, etc) from the modules, and provide a different
entry point to the code base.

There is also a full reference section, as well as extra resources
(glossary, gallery, etc)

Co-authored-by: Shreya Rajpal <ShreyaR@users.noreply.github.com>
2023-01-02 08:24:09 -08:00

1.2 KiB

Key Concepts

Chains

A chain is made up of links, which can be either primitives or other chains. They vary greatly in complexity and are combination of generic, highly configurable pipelines and more narrow (but usually more complex) pipelines.

Sequential Chain

This is a specific type of chain where multiple other chains are run in sequence, with the outputs being added as inputs to the next. A subtype of this type of chain is the SimpleSequentialChain, where all subchains have only one input and one output, and the output of one is therefor used as sole input to the next chain.

CombineDocuments Chains

These are a subset of chains designed to work with documents. There are two pieces to consider:

  1. The underlying chain method (eg, how the documents are combined)
  2. Use cases for these types of chains.

For the first, please see this documentation for more detailed information on the types of chains LangChain supports. For the second, please see the Use Cases section for more information on question answering, question answering with sources, and summarization.