SUBROUTINE aug_knot(X,knots)
! Create knots for Bspline interpolation

	REAL*8, DIMENSION (:), INTENT(in) :: X
	REAL*8, DIMENSION (:), INTENT(out) :: knots
	INTEGER lenX,jk

	lenX=SIZE(X)
	jk=lenX+4
	knots(1:4)=X(1)
	knots(5:jk-4)=X(3:lenX-2)
	knots(jk-3:jk)=X(lenX)

	END SUBROUTINE aug_knot