Introduction
This procedure describes how to setup and execute batch geophysical forward and inversion modelling using the Geomodeller v2 engine. These steps allow the operator to create '.task' files that are used to execute forward model and stochastic potential field inversions on both personal and supercomputers that have Geomodeller v2 installed. The procedure written here was formulated while running inversion modelling on 'billy', a high-performance computer located at the Intrepid Geophysics offices in Brighton, Victoria and on 'savanna' the University of Queensland supercomputer located at St. Lucia campus, Brisbane. This document covers the setup and execution of forward model and inversion procedures for the following potential fields:
- Gravity
- Magnetic
- Joint (Gravity and magnetic inversion conducted in series)
'Task' (.task) files
The parameters for the inversion are contained with a '.task' file (referred to as 'task files' for the remainder of this document) . This is a standard ASCII text file that explicitly describes each parameter in a more understandable manner than the previous '.job' file syntax. Task files use Google protobuf language to manage the inversion processes in Geomodeller v2. Using task files to execute commands in Geomodeller is done in a similar manner as the older '.job' style, but the '.task' file format allows parameters to be identified and specified more easily. Examples of task files and instructions on how to execute them are be provided in later sections.
Preparing a model run
All required parameters for a forward model or inversion are set within the task file. An example of a task file can be found here.
Executing a model run
Task files are executed from the MS-DOS command prompt. It is recommended that task files are executed using a batch (.bat) files, however they can executed directly from the command prompt.
Inversions are executed using a batch, '.bat' file from a DOS command prompt - go to the start menu, left-click on 'run' and type 'cmd' into the 'Run' field and press enter to obtain a DOS command prompt.
Batch and '.task' files can be edited and created using a text editor. While windows comes with text editors, some more useful products that are available are Notepad++ , Programmer's Notepad and UltraEdit.
Important: Examples are used here to explain the manner in which batch and task files can be written. Note that these files are specific to the Geological Survey of Queensland Lawn Hill inversion project and all the parameters defined within should be verified as appropriate for your own project requirements before any inversion processes are executed. This includes the path containted within the batch file. The version installed on other PCs will almost certainly vary from the testing version used here, therefore the path will be different.
In addition, rock properties, inversion iterations, IGRF field parameters and other information sensitive to field area location and project requirements will need to be changed to reflect your own particular requirements.
Submission via batch file
The inversion process is submitted using a batch file. The batch file contains a path to the installation directory of geomodeller and the command that executes the .task file. An example of a batch file setup to conduct a magnetic inversion is as follows:
Italicised sentences should be not be included in your own batch file, they are used here to explain the components of the file. Please delete them if this example is copied and pasted into your own file.
This line sets the path - this is required:
set PATH=D:\apps\admin\bin;C:\GeoModeller\GeoModeller2.0.0.9790e25e3286_x64\bin\server;C:\GeoModeller\GeoModeller2.0.0.9790e25e3286_x64\bin
These lines create a log file 'joblog.txt' which is used to record duration of the process. These lines record the starting time of the process.
echo ---------------- >> joblog.txt
date /T >> joblog.txt
time /T >> joblog.txt
echo Job 'Magnetic inversion' started! >> joblog.txt
echo ---------------- >> joblog.txt
Executed the .task file 'run_magnetic_inversion.task' - this is required.
invbatch -batch run_magnetic_inversion.task
Copies the task file into the output directory (in this case 'OutputGeology') so that a record of the parameters used for the inversion is recorded with the results. This can be useful in case multiple inversions are required using different parameter sets.
copy run_magnetic_inversion.task OutputGeology\
These lines record the end time of the process.
echo ---------------- >> joblog.txt
date /T >> joblog.txt
time /T >> joblog.txt
echo Job 'Magnetic inversion' finished! >> joblog.txt
echo ---------------- >> joblog.txt
Using 'task' files to submit forward modelling requests.
Task files use Google protobuf language to manage batch requests in Geomodeller v2. The serial nature of executing calls to Geomodeller is much the same as the older '.job' style, but the '.task' file format allows parameters to be specified more easily by terms within the file.
Output files
The type and number of output files will depend on the processes that have been selected (see 'Parameters' section above). Essentially a selection of .ers files are output that show either the calculated or measured response of the potential field being analysed. Each set of files, for example effects_Magnetism will include the total field response and separate files for the X, Y and Z components (effects_MagnetismX, effects_MagnetismY, effects_MagnetismZ).