# ARTS built-in documentation server

## Workspace Method jacobianSetAffineTransformation

### Description

Adds an affine transformation of the last element of
jacobian_quantities.
See jacobianSetFuncTransformation for a general description of how
retrieval transformations are defined. Transformations are not applied by
methods such asyCalc. Instead, the method jacobianAdjustAndTransform
must be called to activate the transformations.
The affine transformation is specified by a transformation matrix, A,
and an offset vector, b. These two are applied as described in
jacobianSetFuncTransformation.
The transformations is applied as
x = A * ( z - b )
where z is the retrieval quantity on the standard retrieval grids
and x is the final state vector.
So far, the following must be true for valid A-matrices
z = A'*x + b
That is, the reversed transformation is given by A transposed.
This method must only be called if an affine transformation is wanted.
Default is to make no such tranformation at all.

**Authors: **Simon Pfreundschuh

### Synopsis

### Variables