Editing Documentation:system/seismic (section)

==sfrays3==
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! colspan="4" style="background:#ffdead;" | Ray tracing by a Runge-Kutta integrator in 3-D.
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! colspan="4" | sfrays3 < vel.rsf > rays.rsf shotfile=shots.rsf anglefile=angles.rsf vel=y order=4 nt= dt= sym=y escvar=n zshot=o[0] yshot=o[1] + 0.5*(n[1]-1)*d[1] xshot=o[2] + 0.5*(n[2]-1)*d[2] na= nb= a0=0. amax=360. b0=0. bmax=180. > rays.rsf
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|  colspan="4" | Rays can be plotted with sfplotrays.
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| ''float  '' || '''a0=0.''' ||   || 	First azimuth angle in degrees (if anglefile is not specified)
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| ''float  '' || '''amax=360.''' ||   || 	Maximum azimuth angle in degrees (if anglefile is not specified)
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| ''string '' || '''anglefile=''' ||   || 	file with initial angles (auxiliary input file name)
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| ''float  '' || '''b0=0.''' ||   || 	First inclination angle in degrees (if anglefile is not specified)
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| ''float  '' || '''bmax=180.''' ||   || 	Maximum inclination angle in degrees (if anglefile is not specified)
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| ''float  '' || '''dt=''' ||   || 	Sampling in time
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| ''bool   '' || '''escvar=n''' ||  [y/n] || 	If y - output escape values, n - trajectories
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| ''int    '' || '''na=''' ||   || 	Number of azimuths (if anglefile is not specified)
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| ''int    '' || '''nb=''' ||   || 	Number of inclinations (if anglefile is not specified)
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| ''int    '' || '''nt=''' ||   || 	Number of time steps
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| ''int    '' || '''order=4''' ||   || 	Interpolation order
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| ''string '' || '''shotfile=''' ||   || 	file with shot locations (auxiliary input file name)
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| ''bool   '' || '''sym=y''' ||  [y/n] || 	if y, use symplectic integrator
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| ''bool   '' || '''vel=y''' ||  [y/n] || 	If y, input is velocity; if n, slowness
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| ''float  '' || '''xshot=o[2] + 0.5*(n[2]-1)*d[2]''' ||   || 	shot location crossline (if shotfile is not specified)
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| ''float  '' || '''yshot=o[1] + 0.5*(n[1]-1)*d[1]''' ||   || 	shot location inline (if shotfile is not specified)
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| ''float  '' || '''zshot=o[0]''' ||   || 	shot location in depth (if shotfile is not specified)
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