# 3.3.4. Import weights¶

Under ImportWeights, the user can import cell and face weights used to control the inversion. See the Fundamentals of inversion for more details about the role of weighting matrices.

## 3.3.4.1. Import full weights file¶

ImportWeightsFull weight file

## 3.3.4.2. Import only face weights¶

ImportWeightsOnly faces

## 3.3.4.3. Import Sensitivity as Weights¶

ImportWeightsSensitivity as weights

This option allows to create cell and face weights based on the sensitivity.txt file generated for example by DCINV2D and DCINV3D.

$\mathbf{w_s} = \mathbf{J}_{approx} / max(\mathbf{J}_{approx}) + \delta$
$\mathbf{w_x} = \mathbf{A}_c^{f_x}\mathbf{w_s}$
$\mathbf{w_y} = \mathbf{A}_c^{f_y}\mathbf{w_s}$
$\mathbf{w_z} = \mathbf{A}_c^{f_z}\mathbf{w_s}$

where $$\mathbf{w_s}$$, $$\mathbf{w_s}$$, $$\mathbf{w_s}$$ and $$\mathbf{w_s}$$ are the cell-center and cell-face weights, $$\mathbf{J}_{approx}$$ are the values from the sensitivity.txt file, values from $$\delta$$ is a user-defined threhold parameter ([DEFAULT=1e-2]) and $$\mathbf{A}_c^{f_x}, \mathbf{A}_c^{f_y}, \mathbf{A}_c^{f_z}$$ are averaging operators taking the cell-center values to the respective faces.