SUBROUTINE splint(n,xa,ya,y2a,x,y)
USE Numeric_Kinds_Module
USE CommonInfo_Module
IMPLICIT NONE

LOGICAL found
INTEGER,INTENT(IN):: n
INTEGER klo,khi,ipt
REAL(KIND=dp) x,y,a,b,h
REAL(KIND=dp) xa(n),ya(n),y2a(n)


klo=1
khi=n

found=.false.

DO ipt=1,n
  IF (x.lt.xa(ipt)) THEN
    IF (.not.found) THEN
      found=.true.
      khi=ipt
      klo=ipt-1
    ENDIF
  ENDIF
ENDDO

h=xa(khi)-xa(klo)

IF (h.eq.0.d0) THEN
  PRINT*,'bad xa input in splint'
  STOP 'splint'
ENDIF

a=(xa(khi)-x)/h
b=(x-xa(klo))/h

y=a*ya(klo)+b*ya(khi)+((a**3-a)*y2a(klo)+(b**3-b)*y2a(khi))*(h**2)/6.d0

! y is the output

END SUBROUTINE splint