## DC3DInvRes - Inversion Menu

### Homogeneous model

This resets all model cells (and background resistivities) back to the homogeneous
half-space.

Hotkey for homogeneous model: Shift + H

### Create layered model

Applying a one-dimensional inversion of the whole data set a starting model is
constructed containing the main layering of the underground. The algorithm tries
to equalize neighboring layers if the difference is not very large.
### Full Inversion

The full inversion is carried out using the current options.

Inversion stops when the difference between data and forward response is not
significantly getting better or when the data are fitted within standard deviation.

Hotkey for full inversion: Shift + I

### One inverse step

Only one inverse step (with forward calculation) is calculated (useful for
testing).

Hotkey for one inverse step: 1

### Clear Sensitivity

Sometimes it is useful to clear the sensitivity matrix (for recomputation or saving
disk space).
### Calc Sensitivity

Calculates the (homogeneous half-space) sensitivity matrix (otherwise it is
done automatically before the first inverse step). These sensitivities are (automatically)
saved in a file with the root of the data file plus "-sens.mat". Note,
that every single sensitivity can be viewed by Show
Sensitivies.

### Display depth of investigation

The depth of investigation (DOI) index shows, following (Li and Oldenburgh, 1999),
the dependence on the starting model. One inversion step is carried out using
two different homogeneous half-spaces. The difference between the two models can
be treated as a reliability of the model cells. A well-resolved model cell is
supposed to obtain nearly identical inversion results.
### Show L-curve

If an equation solver for multiple lambda values was applied (Manual Choosing
or L-curve choosing in Inversion Options), the
according L-curve is displayed.

### IP Inversion

A single-step inversion follwing (Beard, Hohmann and Tripp, 1996) is carried
out to obtain a chargeability distribution.