Synopsis
		sflsm_dsr2d < in.rsf > out.rsf slowness=vel.rsf error=error.rsf verb=n eps=0.01 niter=10 nt=1 nr=1 dt=0.004 npad=0

Parameters
		float dt=0.004 time error   float eps=0.01 stability parameter   file error= auxiliary output file name   int niter=10 number of iterations   int npad=0 padding on offset wavenumber   int nr=1 maximum number of references   int nt=1 taper size   file slowness= auxiliary input file name   bool verb=n [y/n] verbosity flag