# Matrix

*Math & Statistics — Finicade finance glossary*

A matrix is a rectangular array of numbers that represents a linear transformation, and it's how portfolios are actually computed. Portfolio variance is a weight vector times a covariance matrix times the weight vector back — one expression that handles a thousand assets and every pairwise interaction between them. Matrix operations are what make large-scale risk and optimisation tractable at all.

**Also known as:** matrices, matrix multiplication, linear algebra

**Related terms:** [Vector and Matrix](https://finicade.com/glossary/vector), [Dot Product](https://finicade.com/glossary/dot-product), [Covariance](https://finicade.com/glossary/covariance), [Cholesky Decomposition](https://finicade.com/glossary/cholesky-decomposition), [Eigenvalue](https://finicade.com/glossary/eigenvalue)

**Taught in:** Math Masters — Matrices & Portfolio Variance

Source: https://finicade.com/glossary/matrix