# Accumulation, Assignments and Index Operators

Learn how to overload accumulation and indexing operators for the Matrix class.

## Introduction to the accumulation operators

An **accumulation operator** is a mathematical function that takes a sequence of values and produces a running total of those values. It’s also sometimes called a **summation operator** or **cumulative sum**.

The most common symbol used to represent the accumulation operator is the Greek capital letter *Sigma* (

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