OCTAVE FwdR1

This code uses the same formulation as invR1.m program (see section 8.1.1). The function rwv.f is built from DISPER (9.2.6). It computes a single forward problem described in the same way as in the inverse problem.
 This program computes a demonstration Rayleigh wave dispersion
curve.  It uses rwv.f fortran function which must be compiled and
linked to expand octave capability.  The required files include:
rwv.f
wrapper.cpp
build_disper_oct (make executable, chmod +x if not)

Either run the build script first or start an octave session
and be prompted to build the extension inside the octave run.

A file, like model.txt, contains the layered earth velocity model.
Control points are interpolated by layers linearly interpolated
by elastic parameters, not velocity.

Control Point file, like model.txt, is as follows:
1. first line is number of layers
2. second line is S-wave velocities
3. third line is depth values where those velocities apply.
   |Example: for nlay=3 vi=shear velocity, zi=depth layer top   |
   | nlay                                                       |
   | v1 v2 v3                                                   |
   | z1 z2 z3      
GUI prompts are available for relating P-wave velocity to S-wave velocity.
The layer thickness, once entered, will be held constant during
the run of all other model changes.

Also plotted are actual observed data (see line 275).  Running this program over
and over again, one can manually invert the observed data in
bvax.his (see program BVAX), by trying to fit the observed data
with a computed curve.

The disper() function returns a vector pv with fundamental
and any higher modes.  Here, it is demonstrated how to
select and plot fundamental mode.