# ARTS built-in documentation server

## Workspace Method covmat_sxExtractSqrtDiagonal

### Description

Extract the square root of the diagonal of the state space covariance matrix.
This function extracts the diagonal of the state space covariance matrix
covmat_sx and computes its square root. The resulting vector can then
be used as ``x_norm`` argument for the OEM method to avoid scaling problems.

**Authors: **Simon Pfreundschuh

### Synopsis

covmat_sxExtractSqrtDiagonal( | x_norm, covmat_sx ) |

### Variables

GOUT | x_norm | (Vector) | The vector containing the square root of the diagonal elements of covmat_sx |

IN | covmat_sx | (CovarianceMatrix) | Covariance matrix of a priori distribution This covariance matrix describes the Gaussian a priori distribution for an OEM retrieval. |