# DIAG matrix function

## Description

DIAG(**A**) Creates a diagonal matrix. The matrix argument can be either a numeric square matrix or a vector.

If matrix **A** is a **square matrix**, the DIAG function creates a column vector with its elements *e _{r}* equal to the corresponding diagonal elements

*e*of

_{r,r}**A**.

If matrix **A** is a **vector**, the DIAG function creates a matrix with diagonal elements *e _{r,r}* that are the values

*e*in the vector. All off-diagonal elements are zeros.

_{r}## Examples

DIAG({1,9,8}) returns {1,0,0|0,9,0|0,0,8}

DIAG({1,9,8|1,2,7|6,8,3}) returns {1|2|3}

DIAG(DIAG({1,9,8|1,2,7|6,8,3})) returns {1,0,0|0,2,0|0,0,3}

## Calculator

## See also

## Recommended book

## Matrix Algebra Useful for Statistics

Shayle R. Searle, Andre I. Khuri

Buy from Amazon

This book addresses matrix algebra that is useful in the statistical analysis of data as well as within statistics as a whole. The material is presented in an explanatory style rather than a formal theorem-proof format and is self-contained.