Appendix

from rsf.proj import *

# Retrieve data
Fetch('vp_marmousi-ii.segy',"marm2")

# Processing units will be m and s.  
# Input vel file is in km/s. mult by 1000 to m/s
# Use km in space domain and km/s for velocity

Flow('vp vp_hdr vp_hfile.txt vp_hfile.bin','vp_marmousi-ii.segy', 
     ''' 
     sfsegyread tape=$SOURCE tfile=${TARGETS[1]}                  hfile=${TARGETS[2]} bfile=${TARGETS[3]}       | sfput d1=1.249 o1=0 label1=Depth    unit1=m              d2=1.249 o2=0 label2=Distance unit2=m        | sfwindow min1=0 max1=2000 min2=0 max2=5000 j1=10 j2=10       | sfmath output='input*1000'
     ''')

# plot the input velocity.  Use allpos=y to plot velocity.
Result('vp',
       '''
       grey color=j titlefat=4 titlesz=8 labelfat=4 labelsz=8 
            screenratio=1.0 barwidth=0.6
            allpos=y scalebar=y n1tic=50 n2tic=40 verb=y 
            title="Original Velocity"
       ''')

# smooth for vp finite difference modeling and plot. (allpos=y for velocity)
Flow('vpforward','vp','smooth rect1=3 rect2=3 repeat=3') 
Result('vpforward',
       '''
       grey color=j titlefat=4 titlesz=8 labelfat=4 labelsz=8 
            screenratio=1.0 barwidth=0.6
            allpos=y scalebar=y n1tic=50 n2tic=40 verb=y 
            title="Smooth Velocity for Modeling"
       ''')

# smooth vp for nmo/migration and plot. (allpos=y for velocity)
Flow('vpmigration','vp','smooth rect1=10 rect2=10 repeat=5') 
Result('vpmigration',
       '''
       grey color=j titlefat=4 titlesz=8 labelfat=4 labelsz=8 
            screenratio=1.0 barwidth=0.6
            allpos=y scalebar=y n1tic=50 n2tic=40 verb=y 
            title="Smooth Velocity for Migration"
       ''')

# model 10 shotpoints
# put for sftah... need d3, distance between shotpoints.
#kls need to add parameter time=time.rsf (default is time without .rsf)
Flow('shots sfmodelingtime','vpforward',
        '''
        sfmodeling2d csdgather=n fm=10 amp=1 dt=0.0015 ns=10 ng=400 nt=2000
            sxbeg=1 szbeg=1 jsx=40 jsz=0 gxbeg=0 gzbeg=0 jgx=1 jgz=0 
            time=${TARGETS[1]} 
        | sfput d3=500 label3=sx label2=gx unit2=traces o3=0
        ''')

# plot all 10 shots as movie
Result('shots',
       '''
       sfgrey color=j titlefat=4 titlesz=8 labelfat=4 labelsz=8 
            screenratio=1.0 
            allpos=n scalebar=n n1tic=50 n2tic=40 
            title="fd modeled shots"
       ''')

# plot shot at x=2500 for paper
Result('shot2500','shots',
       '''
       sfwindow n3=1 min3=2500 |
       sfgrey color=j titlefat=4 titlesz=8 labelfat=4 labelsz=8 
              screenratio=1.0 
              allpos=n scalebar=n n1tic=50 n2tic=40 
              title="fd modeled shot"
       ''')

# make velocity field constant 1500 m/s and model direct arrivals
Flow('arr sfmodelingtime1','vpforward',
     '''
     sfmath output="1500" |
     sfmodeling2d csdgather=n fm=10 amp=1 dt=0.0015 ns=10 ng=400 nt=2000
         sxbeg=1 szbeg=1 jsx=40 jsz=0 gxbeg=0 gzbeg=0 jgx=1 jgz=0
            time=${TARGETS[1]} 
     ''')

# subtract modeled direct arrivals (a type of noise) from shots
Flow('mutearr','shots arr',
     '''
     sfadd scale=-1,1 ${SOURCES[1]}
     ''')

# plot all 10 shots as movie
Result('mutearr',
       '''
       sfgrey color=j titlefat=4 titlesz=8 labelfat=4 labelsz=8 screenratio=1.0 
              allpos=n scalebar=n n1tic=50 n2tic=40 
              title="First Arrival Removed"
       ''')

# plot shot at x=2500 for paper
Result('mutearr2500','mutearr',
       '''
       sfwindow n3=1 min3=2500 | 
       sfgrey color=j titlefat=4 titlesz=8 labelfat=4 labelsz=8 screenratio=1.0 
              allpos=n scalebar=n n1tic=50 n2tic=40 
              title="First Arrival Removed"
       ''')

dt = 0.0015
# stretch velocity from depth to time
Flow('vel_t','vpmigration',
     'sfdepth2time velocity=${SOURCES[0]} dt=%g nt=2000'%(dt))
# generate rms velocity :
# input is vel_t the vlocity stretched to time
# sfmul multiply input data by itself to make v**2
# sfcausint integrate v**2 (this does not include scaling by dt)
# sfmath scale by dt and divide by t
Flow('vrms','vel_t',
     '''
     sfmul $SOURCE | 
     sfcausint |
     sfmath output="sqrt(input*%g/(x1+%g))" |
     sfput n3=1 d3=1 o3=0 
     '''%(dt,dt))

# sftahnmo requires velocity in m/s for every cdp.  
# d2=12.49, but cdp int is half this (ie 6.245 or 12.49/2)
# interleave the velocity to double the number of traces.  Should
# interpolationm but this will be pretty good.

Flow('vrms2_m','vrms vrms',
     '''
     interleave axis=2 ${SOURCES[1]} | 
     put d2=6.245
     ''') 

#Make an empty file for the segy headers.  SEGY standard contains 91 rows
Flow('mutearr_hdr.rsf',None,
     '''
     math n1=91 n2=4000 output="0"
     ''')

# build trace headers for the synthetic traces.  Will be used to sort traces.
Flow('Mmutearr.rsf Mmutearr_hdr.rsf','mutearr.rsf mutearr_hdr.rsf',
     '''
	 sftahread input=${SOURCES[0]} makeheader=y
         | sftahheadermath outputkey=gx output="gx"
         | sftahheadermath outputkey=sx output="sx"
         | sftahheadermath outputkey=cdpx output="(gx+sx)/2"
         | sftahheadermath outputkey=cdp output="int(cdpx/6.245)"
         | sftahheadermath outputkey=offset output="abs(sx-gx)"
         | sftahgethw key=sx,gx,cdp,cdpx,offset
         | sftahwrite  
        verbose=1              
        mode=seq             
        output=${TARGETS[0]}
        outheaders=${TARGETS[1]} 
     ''',stdout=0,stdin=0)

# make cdp gathers for displays. Not used in this script
Flow('CDP CDP_hdr','Mmutearr.rsf Mmutearr_hdr.rsf',
      '''
      sftahsort input=$SOURCE sort="cdp offset"
      | sftahwrite output=${TARGETS[0]}
        mode=seq             
      ''',stdout=0,stdin=0)

# Sort to cdp gathers, remove selay in ricker wavelet, 
# gain for spreading correction, biuld headers used by sftahnmo to read
# space variant velocity, and stack the data
Flow('stack.rsf stack_hdr.rsf','Mmutearr.rsf Mmutearr_hdr.rsf vrms2_m.rsf',
     '''
      sftahsort input=$SOURCE sort="cdp offset"
      | sftahheadermath outputkey=sstat output=-250
      | sftahstatic sign=-1
      | sftahgain tpow=1.5             
      | sftahheadermath outputkey=xline output=cdp*6.245
      | sftahheadermath outputkey=iline output=0
      | sftahnmo vfile=vrms2_m.rsf
      | sftahstack key=cdp xmute=0,5000 tmute=0,5
      | sftahwrite output=${TARGETS[0]} mode=seq
     ''',stdout=0,stdin=0)
# can use this line for v(t) velocity in sftahnmo
#      | sftahnmo tnmo=0,1,2,2.5,3,4 vnmo=1510,1600,1700,1800,1900,1980

# Display the stack
Result('stack',
       '''
       grey pclip=99 titlefat=4 titlesz=8 labelfat=4 labelsz=8 barwidth=0.6
       allpos=n scalebar=n n1tic=50 n2tic=40 verb=y screenratio=1.0 
       title="NMO and Stack"
       ''')

# Kirchhoff migration and display
Flow('ktmig','stack.rsf vrms2_m.rsf',
     '''
     put d2=6.25 |
     kirchnew velocity=${SOURCES[1]}
     ''')
Result('ktmig',
       '''
       grey pclip=98 titlefat=4 titlesz=8 labelfat=4 labelsz=8 barwidth=0.6
       allpos=n scalebar=n n1tic=50 n2tic=40 verb=y screenratio=1.0 
       title="Kirchhoff Post Stack Mig"
       ''')

# Kichhoff least squares migration and display.
Flow('invsparse err_sparse','stack vrms2_m.rsf',
     '''
     put d2=6.25 |
     kirchinvs velocity=${SOURCES[1]} niter=1 liter=3 ps=1
     err=${TARGETS[1]} verb=1
     ''')
Result('invsparse',
       '''
       grey pclip=98 titlefat=4 titlesz=8 labelfat=4 labelsz=8 barwidth=0.6
       allpos=n scalebar=n n1tic=50 n2tic=40 verb=y screenratio=1.0
       title="Least-Squares Kirchhoff Mig"
       ''')

End()