## Optimization of the Shape of Gaussian Beams

This is an example how to prepare the optimum initial parameters
of Gaussian beams (GBs) for Marmousi model. It is based on the paper
'Optimization of the Shape of Gaussian Beams, Seismic Waves in Complex
3-D Structures, Report 11 (Prague 2001), pp. 181-201'.

To calculate the optimum initial parameters of GBs, compile packages
**FORMS**, **CRT** and **MODEL** with parameter MRAM in file
'ram.inc' equal at least to MRAM=8000000.
After
that, launch history file 'gb-inv.h'. There are two
parameters in the file that can be easily edited - **CPAR1** and
**SOBMUL**. The position of the source is controled by **CPAR1**.
Smoothing is controled by parameter **SOBMUL**, repeated several
time in history file 'gb-inv.h'. The values of parameter **SOBMUL**
correspond to factors *s*_{Y} and *s*_{R}
(see eqs. 82, 89 and 90 in the paper).

### Notes on history file 'gb-inv.h'

First of all, this history file launches another history file
'gb-opt.h', which is designed to calculate the optimum
initial parameters of GBs transformed to initial surface. Calculation of the
initial parameters of GBs is performed by program
'gbopt.for'.

After that, the initial parameters of GBs are smoothed (in this case with two
iterations).

Then, history file 'gb-test.h' is launched
to calculate and plot the widths of Gaussian beams.