Transformation of 2-D displacement into "normalized" rotation ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Input: @1... Displacement derivative dU1/dX3 @2... Displacement derivative dU3/dX1 $3... S wave velocity $4... Density Output: @5... X2 component of the rotation of the input wavefield, multiplied by SQRT(density*VS**3) in order to locally preserve maximum amplitudes during the propagation across interfaces. Commands for grdps.for: ~~~~~~~~~~~~~~~~~~~~~~~ rot=@1-@2 a=$3*$4 a=SQRT(a) a=$3*a @5=rot*a