Tomofast-x v.2.0

Major components added:

• Sensitivity kernel wavelet compression.
• Inversion for magnetisation vector (including remanence).
• Inversion of the 3-component magnetic data.
• Efficient parallelisation scheme.
• Support of topography.
• Support of the non-uniform model grids.
• Support of the drillhole data.

In addition the following code improvements have been implemented:
• A flexible input parameter format which allows for the specification of input code parameters by their names, placed in any order with unneeded parameters left out making the parameter files cleaner and more readable.
• Storing the compressed sensitivity kernel as binary files allows for previously computed sensitivity kernels to be reused, when for example, the weights of the cost function constraints are adjusted or when a different background field is subtracted from the data as these do not affect the sensitivity kernel values. Additionally, the calculated kernel can be imported into other codes, for example in Python codes, to perform sensitivity analysis, null-space navigation, etc.
• I/O was optimised for better performance: (1) Paraview visualisation files (in vtk format) were converted from ASCII to binary format, to minimise the size and (2) Fortran arrays are written to a file in a single statement, rather than through a loop
• The memory allocation was reduced by avoiding allocation of some arrays. This is especially important for shared memory machines where the memory size is constant and does not scale with the number of CPUs, unlike the distributed memory machines.
• Avoided temporary array creation which was confirmed by the “-Warray-temporaries” GCC flag.
• Maintaining no external dependencies except the MPI parallel library, which makes the code easy to port to different machines and operating systems.
• Assuring Fortran2008 compliance by using the GCC flag “-std=f2008”.
• Added local weights for each directional component (x, y, z) of the gradient damping constraint.

Tomofast-x v.1.1 geophysical joint and constrained parallel inversion code.

• Changed the parameters file (Parfile) format to allow the dynamic parameters specified by their names.
• Added the User Manuel.