 
      FUNCTION CBRT(X)
C***BEGIN PROLOGUE  CBRT
C***DATE WRITTEN   770601   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  C2
C***KEYWORDS  CUBE ROOT,ELEMENTARY FUNCTION
C***AUTHOR  FULLERTON, W., (LANL)
C***PURPOSE  Computes the cube root of X.
C***DESCRIPTION
C
C CBRT(X) calculates the cube root of X.
C***REFERENCES  (NONE)
C***ROUTINES CALLED  R1MACH,R9PAK,R9UPAK
C***END PROLOGUE  CBRT
 
 
