SUBROUTINE Bspline2f(X0, lgT0, lgQs0, Ys)

! perform Bspline interpolation of SAHA-S3 tables
! for given X0, lgT0, lgQs0.
! Bspline2f computes only two values Ys(1) and Ys(5)
! instead of all 12 (as Bspline does).

	IMPLICIT NONE

! Variables

	REAL*8, INTENT(in) :: X0, lgT0, lgQs0
	REAL*8, DIMENSION(mv), intent(out) :: Ys

	INTEGER ix,iT,iQs,iv
	INTEGER LCX, LCT,LCQs
	REAL*8, DIMENSION(Jspline) :: BIATX, BIATT, BIATQs
	REAL*8 bttt

! Body of Bspline2f

	CALL BSPLVB8v( Xknot, Jspline, X0, LCX, BIATX )
	CALL BSPLVB8v( Tknot, Jspline, lgT0, LCT, BIATT )
	CALL BSPLVB8v( Qsknot, Jspline, lgQs0, LCQs, BIATQs )

	Ys=0.d0
	DO ix=1,Jspline
	 DO iT=1,Jspline
	  DO iQs=1,Jspline
	   bttt=BIATX(ix)*BIATT(iT)*BIATQs(iQs)
	   DO iv=1,5,4
	    Ys(iv)=Ys(iv)+Beos(LCQs+iQs-1,LCT+iT-1,iv,LCX+ix-1)*bttt
	   ENDDO
	  ENDDO
	 ENDDO
	ENDDO

	RETURN

	END SUBROUTINE Bspline2f