Synopsis
		sfspiral > spiral.rsf nx=500 ny=200 xmax=20. ymax=3. xmin=0. ymin=0. dx=(xmax-xmin)/(nx-1) dy=(ymax-ymin)/(ny-1) xc=10. yc=5. eps=1.0e-6 v0=2.0 v1=2.0 r0=1.0 r1=0.4 b=0.1 fac=0.2 sp_r=1. sp_t=0.05

Parameters
		float b=0.1 exponential decay factor   float dx=(xmax-xmin)/(nx-1)   float dy=(ymax-ymin)/(ny-1)   float eps=1.0e-6   float fac=0.2   int nx=500   int ny=200   float r0=1.0   float r1=0.4 paramters of original shape   float sp_r=1. speed in radius   float sp_t=0.05 speed in angle   float v0=2.0   float v1=2.0   float xc=10.   float xmax=20.   float xmin=0.   float yc=5.   float ymax=3.   float ymin=0.

Used In
		TCCS          time2depth/msyn2 time2depth2/synth