readme

su 的源代码库

In this directory, we supply the files to recreate Example 1 of the
CXZCO release notes.			jkc (06/25/91)


Environmental Note:
To run this demo, you need a recent version of the CWP/SU (Seismic
Unix) package available by anonymous ftp from CWP at hilbert.Mines.EDU
(138.67.12.63).

Graphics Note:
The shells given here all use X graphics.  To use PostScript graphics,
remove the trailing ampersand (&) that puts the X Window into
background and replace it with either a pipe (|) or output (>) as
appropriate on your system.  You may want to specify the nbpi parameter
and make other tweaks for hard copy.

Synthetic Data Note:
The synthetic is made with CSHOT which uses files with similar
names to CXZCO.  To keep this Demo directory uncluttered, the synthetic
data is made in the subdirectory:   model.dir
This is where you have to go to tweak the model or change the data
recorded over it.  The sordid details are given later in this file.

Preprocessing Note:
The CXZCO inversion theory requires application of a fractional
derivative filter before the Kirchhoff-like summation.  This
"pre processing" step is carried out by CZ1 and its data validator,
CZ1IN.  These programs and the fft, FFTPACK, that they use is
distributed with CXZCO and are installed with the same Makefile.
You don't have to know anything about this, just imitate the usage
in the Inversion shell.

Inversion Note:
See the CXZCO release notes for a description of the param file--this
is the KEY file guiding the inversion.  To keep this Demo directory
uncluttered, the inversion parameter files are kept in the subdirectory:
inversion.dir

FORTRAN vs. C NOTE:
The modeler and inverter are written in Fortran.  Our graphics
is written in C.  Fortran adds inter-trace bytes that C doesn't
expect.  SU can take care of this, but we decided to simply
supply a program, ftnstrip, that takes care of this problem.
Again, just imitate the usage in the Synthetic and Inversion
shells.

Normal usage pattern is to run each of
Model
Inversion

Files in this directory:
README		- this file

Model		- a shell to create model and synthetic data (step 1)
Inversion	- a shell to do the inversion (step 2)
record.cwp	- the output we got from the inversion phase
model.dir	- a DIRECTORY containing the modeling parameter files
inversion.dir	- a DIRECTORY containing the inversion parameter files
Clean		- a shell to clean up the files created during the demo

The Sordid Details:
Note that if you are JUST inverting, so that you have data
to begin with, your job is MUCH simpler than the interfacing
of CSHOT and CXZCO described here.

The Model file is a Bourne shell that uses cshot1 and CWP X graphics to
display the model with a fan of rays emerging from the subsurface.
Ordinarily this is something you would do earlier in the synthetic data
cycle to determine a suitable model.  See the CSHOT release notes and
Demos for some good examples.  This shell depends on the following files
to be found in the syntheticdata subdirectory:

param1.model- this is needed by cshot1
		Note that Model copies this file to the name "param"
		as required by cshot1
model       - name defined in param1.model; defines the model interfaces
		Note that CSHOT requires the upper surface to be defined
		in the model (to allow curved upper surfaces), while
		the corresponding file, simple, for the inversion does
		not have the upper surface entry (you wondered maybe
		why I said "sordid" details?)
modelgeometry - name defined in param1.model; defines the shot-receiver layout
		See the README in the syntheticdata subdirectory for a
		discussion of simulating the common offset inversion geometry.
plotcolors    - name defined in param1.model; defines the X color table


The Synthetic file is a Bourne shell that uses cshot1 to create a
common offset section and uses CWP Xgraphics to display both
the primary rays and the time section.  Again, see the CSHOT release notes
and Demos for good examples.  The output synthetic data section is
called demo1traces and the shell moves it into this directory for the
inverter to work on.  This shell depends on the following files
to be found in the syntheticdata subdirectory:

param1.traces- this is needed by cshot1
		Note that Model copies this file to the name "param"
		as required by cshot1
param2       - needed by cshot2
model        - name defined in param1.traces; same file as for the Model shell
geometry     - name defined in param1.traces; defines the shot-receiver layout
		Note that this file is different from the modelgeometry file
		since now our job is to shoot rays from the surface.
plotcolors   - name defined in param1.traces; defines the X color table

The Inversion file is a Bourne shell that uses CZ1IN, CZ1 and CXZCO
to invert the synthetic section and uses CWP X graphics to display
the inverted section.  This shell depends on the following files to
be found in THIS directory (and described earlier):

BOUNDS
data1in
param
simple