Synopsis
		sfmutter < in.rsf > out.rsf offset=offset.rsf half=y nan=n tp=0.150 t0=0. v0=1.45 slope0=1./v0 slopep=slope0 x0=0. abs=y inner=n hyper=n

Data is smoothly weighted inside the mute zone.
The weight is zero for t < (x-x0) * slope0
The weight is one for t > tp + (x-x0) * slopep

The signs are reversed for inner=y.

Parameters
		bool abs=y [y/n] if y, use absolute value |x-x0|   bool half=y [y/n] if y, the second axis is half-offset instead of full offset   bool hyper=n [y/n] if y, do hyperbolic mute   bool inner=n [y/n] if y, do inner muter   bool nan=n [y/n] if y, put nans instead of zeros   string offset= auxiliary input file name   float slope0=1./v0 slope   float slopep=slope0 end slope   float t0=0. starting time   float tp=0.150 end time   float v0=1.45 velocity   float x0=0. starting space

Used In
		BEI          dpmv/krchdmo sg/denmark vela/vscan wvs/vscan   DATA          sigsbee/nfs2B sigsbee/fs2B sigsbee/ptest sigsbee/data2A   GEE          mda/pefex   GEO384W          hw3/cmp   GEO391          hw4/match   JSG          diffr/fault flat/flatelf pmig/mig pmig/nmo seislet/gath shape/beivc simistack/bei simistack/flat4   RSF          scons/rsf su/rsflab16 usp/data   SEP          cdstep/veltran oc2/elfshot pwd/hector pwd/dune stack/velinv steer/wz25 vc2/beivc