README

Description of files:
1) model.scr computes the model and the 'basis' shot of R => shot5_rp.su
2) p5all.scr create from basis shot full Reflection response matrix => shotsdx5_rp.su (3.3 GB)
3) initialFocus.scr model G_d the intitiAla focusing function => iniFocus_rp.su
4) referenceShot.scr creates the reference Green's function at focal point => referenceP_rp.su
5) marchenko.scr perform the Marchenko scheme => pgreen.su, f1plus0.su, f1min0.su, f2.su

extra scripts
marchenkoIter.scr to make the figure with "Four iterations of the Marchenko method."

backpropf2.scr to make Figure "Snapshots of back-propagation of f_2."

eps*.scr reproduce the postscript files of the manuscript using SU postscript plotting programs.


To reproduce the Figures in the Manuscript:

--------------------------
* Figure 2: Wavelet
* Figure 3: Model + Initial wavefield

==> run model.scr to generate the data .su files: this will take 3-4 minutes. The files generate are:
	- hom_cp.su, hom_ro.su
	- model10_cp.su, model10_ro.su
	- shot5_fd_rp.su
	- shot5_hom_fd_rp.su
	- shot5_rp.su
	- wave.su
	- wavefw.su

==> run initialFocus.scr to compute the direct arrival of the transmission response G_d. This will take 1-2 minutes.
	- modelup_cp.su
	- modelup_ro.su
	- iniFocus_rp.su

==> run epsModel.scr to generate the postscript files of Figure 2 and 3

wavefw.eps 		=> Figure 2a
wavefw_freq.eps		=> Figure 2b

model_cp_line.eps 	=> Figure 3a 
model_ro_line.eps 	=> Figure 3b
shotx0_rp.eps 		=> Figure 3c
iniFocus_rp.eps 	=> Figure 3d


--------------------------
* Figure 4: Initialisation
* Figure 5: first update
* Figure 6: first 4 iterations

The full R matrix is build up from the the shot record computed with model.scr

==> run p5all.scr to generate the full R matrix for a fixed spread geometry. This will take less than one minute. The file generated is
	- shotsdx5_rp.su the file has a size of 3.3 GB

This R, together with iniFocus_rp.su, is the input of the Marchenko algorithm

==> run marchenkoIter.scr to compute the first 4 iteration of the Marchenko algorithm. This will take 1-2 minutes. The generated files are:
	- p0plus.su
	- pgreen_001.su
	- f1plus_001.su
	- f1min_001.su
	- Gplus_001.su
	- Gmin_001.su
	- pgreen_002.su
	- f1plus_002.su
	- f1min_002.su
	- Gplus_002.su
	- Gmin_002.su
	- pgreen_003.su
	- f1plus_003.su
	- f1min_003.su
	- Gplus_003.su
	- Gmin_003.su
	- pgreen_004.su
	- f1plus_004.su
	- f1min_004.su
	- Gplus_004.su
	- Gmin_004.su

To Compute the reference Green's function at x=0 z=900 m in the actual model
==> run referenceShot.scr  This will take 1 minute and generates the file;
	- referenceP_rp.su

To generate all postscript files for Figure 4, 5 and 6

==> run epsMarchenkoIter.scr


shotx0_rp.eps 		=> Figure 4 R == Figure 3c
p0plus.eps	 	=> Figure 4 G_d
iter_001.eps	 	=> Figure 4 N_0

shotx0_rp.eps 		=> Figure 5 R == Figure 3c
f1min_001.eps	 	=> Figure 5 f^-_1,0
iter_002.eps	 	=> Figure 5 -N_1
f1plus_002.eps	 	=> Figure 5 f^+_1,0

-- Figure 6 column 1
iter_001.eps
iter_002.eps
iter_003.eps
iter_004.eps
-- Figure 6 column 2
f1min_001.eps
f1min_002.eps
f1min_003.eps
f1min_004.eps
-- Figure 6 column 3
p0plus_flip.eps
f1plus_002.eps
f1plus_003.eps
f1plus_004.eps
-- Figure 6 column 4
pgreen_001.eps
pgreen_002.eps
pgreen_003.eps
pgreen_004.eps
-- Figure 6 column 5
compare_001.eps
compare_002.eps
compare_003.eps
compare_004.eps

--------------------------
* Figure 7: Comparison of Marchenko result with reference

To compute the marchenko results for 8 iterations.  

==> run marchenko.scr This will take less than 1 minute. The generated files are:
	- pgreen.su, pgreen512.su
	- diffref.su
	- Gplus0.su
	- Gmin0.su
	- f1plus0.su
	- f1min0.su
	- f2.su 


At the end of the run the script will display in X11 a comparison of the middle trace. 

To make the postscript figure 

==> run epsCompare.scr

mergeGreenRef.eps 	=> Figure 7

--------------------------
* Figure 8: snapshots of back propagating f2 in actual medium 

To compute the snapshots 

==> run backpropf2.scr This will take about 1 minute. The generated output file is
	- backpropf2_sp.su

The postscript files of Figure 8 are generated with 

==> run epsBackprop.scr

-- Figure 8 column 1
backpropf2_-0.30.eps
backpropf2_-0.15.eps
backpropf2_-0.03.eps
backpropf2_-0.02.eps
backpropf2_0.00.eps
-- Figure 8 column 2
backpropf2_0.30.eps
backpropf2_0.15.eps
backpropf2_0.03.eps
backpropf2_0.02.eps
backpropf2_0.00.eps
-- Figure 8 column 3
backpropf2sum_0.30.eps
backpropf2sum_0.15.eps
backpropf2sum_0.03.eps
backpropf2sum_0.02.eps
backpropf2_0.00.eps


The figures in the appendix, to explain the different options in the programs, are reproduced by

==> run figAppendi.scr

-- Figure A-1
noise_above0.eps
noise_above1.eps
noise_above-1.eps
noise_above2.eps
noise_above4.eps

-- Figure A-2
iniFocus_shifts.eps