4.4.5. refine_octree

This utility is designed to refine a previously created octree mesh at intermediate iteration steps to make it finer, given the corresponding octree conductivity or chargeability model. The idea is that a balance needs to be maintained between the accuracy of the forward model and the computational speed. It is therefore expected that on the first run, the data will be fit to an increased chifact on a rather coarse mesh. The mesh should be refined again so that at each refinement step, the data can be fit to a progressively decreasing chifact, which will eventually become 1.

Unlike the discretization process for the initial mesh (which was only dependednt on electrode locations), the post-refinement discretization will also be based on the curvature of the model. Regions with more abrupt physical property variatons will be discretized to a greater degree (although not smaller than the initial underlying base mesh).

To call this utility, use the following command from a command prompt:

refine_octree refine_mesh.inp

This utility requires a control file (i.e., refine_mesh.inp) to exist in the working directory.

4.4.5.1. Control parameters and input files

The following is the control file format:

The input paramers for the control file are:

LOG_MODEL | LIN_MODEL

Linear versus logarithmically scaled model file. LOG_MODEL is typically used for DC conductivity models while LIN_MODEL is usually used for IP chargeability models.

input octree mesh file

Filename for the initial octree mesh.

input octree model file

Filename for the initial octree model.

output octree mesh file

Desired filename for the refined octree mesh.

output octree model file

Desired filename for the refined octree model.

4.4.5.2. Output files

refine_mesh.log

Log file specifying the parameters used by the refine_octree utility.

output octree mesh

The refined octree mesh.

output octree model

The refined octree model.