Transformation of 2-D displacement into "normalized" divergence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Input: @1... Displacement derivative dU1/dX1 @2... Displacement derivative dU3/dX3 $3... P wave velocity $4... Density Output: @5... Divergence of the input wavefield, multiplied by SQRT(density*VP**3) in order to locally preserve maximum amplitudes during the propagation across interfaces. Commands for grdps.for: ~~~~~~~~~~~~~~~~~~~~~~~ div=@1+@2 a=$3*$4 a=SQRT(a) a=$3*a @5=div*a