REAL FUNCTION PEN ( I, K, F )
Argument Definitions (+ indicates altered content)
INTEGER            I,          K
REAL               F
Description
THIS ROUTINE CALCULATES THE RETARDATION FOR A PARABOLIC LAYER
Source file:pen.f
Intrinsic Functions Called
REAL               ALOG,       AMAX1
Local Variables (+ indicates altered content)
REAL              +X
Referenced Common Block Variables (+ indicates altered content)
RON                REAL               FI(3,5),   YI(3,5)