gremlin is located at src/green/gremlin1.
Joint inversion of Fourier-Bessel expansion coefficients and refracted P-wave travel times.
Array size adjustment
The Fortran 77 program uses fixed size array.
Since it has to store the complete matrix of partial derivatives, memory
requirements may become significant.
Array sizes therefore are to be carefully adjusted.
In particular the number of slowness values and frequencies in the input data
(Fourier Bessel expansion coefficients) must not exceed the array size.
In case you experience problems, please use the program
Problems with array size
med: edit model within gremlin
med saves the current model to a file called
then calls the text editor to allow model modification.
vim editor is hardwired in the source code.
After closing the editor, the modified file is read for further use in gremlin.
This function is implemented at:
dgr: display expansion coefficients used as data
dgr displays the modulus (amplitude) of the expansion
coefficients which are read from file and used within gremlin as data in four
- expansion coefficients as read from file, full frequency and slowness range
- expansion coefficients as read from file, selected frequency and slowness range is displayed only
- expansion coefficients after application of scaling function selected by green data mode, full frequency and slowness range
- expansion coefficients after application of scaling function selected by green data mode, selected frequency and slowness range is displayed only
Tips and tricks
What can I do if I do not have refracted P-wave traveltimes available?
If you do not like to use the travel-time information at all, just set bala to 1.
- first enter command "spa"
- the enter command "bala 1." This will apply a weight of 0. to the the travel time residuals. The will then have no more effect within the inversion and travel time picks are allowed to be entirely meaningless. Only information from the expansion coeffients will be used for the inversion.